Medical News

Do doctors confuse ME with a heart problem?

Medical News - Tue, 06/17/2014 - 14:17

“ME: one third of patients ‘wrongly diagnosed’,” says The Daily Telegraph, which has reported on a new study of a condition called postural tachycardia syndrome (PoTS).

In PoTS, the heart rate increases by over 30 beats per minute when standing, causing dizziness, fatigue and other symptoms that impact a person’s quality of life (for a full list, read the PoTS UK advice on PoTS symptoms).

Researchers wanted to find out some of the characteristics of people who had PoTS, and whether the condition has any similar characteristics to chronic fatigue syndrome (CFS). The media headlines have used this latest study to focus on previous research that found around a third of people with a diagnosis of CFS/myalgic encephalitis (ME) actually had PoTS.

It is unclear from this latest report whether these people had been “wrongly diagnosed”, or whether they had both PoTS and CFS. In the new study, 20% of people with PoTS also had a diagnosis of CFS.

Unfortunately, there are no cures for either condition – instead, doctors help people to manage their symptoms and reduce the impact on their quality of life. Beta-blockers were the most commonly used treatment for the symptoms of PoTS in this study, but there were a total of 21 (of a possible 136) different treatments used, and some patients received no treatment at all.

The researchers speculate that those who did not have any treatment may have experienced side effects or no improvement, compared to those who did have treatment. The results also showed very little difference in symptoms, regardless of whether medication was taken.

 

Where did the story come from?

The study was carried out by researchers from Newcastle University and was funded by the UK National Institute for Health Research (NIHR) Biomedical Research Centre in Ageing.

The study was published in the peer-reviewed medical journal BMJ Open. The article is open-access, meaning the research is free to view and download online.

The media reported that a third of people are being wrongly diagnosed with CFS when they have PoTS, which is “treatable”. However, this is not what the latest study found. Instead, it highlights that very little is known about both conditions, although it did find that there is a degree of crossover between PoTS and CFS/ME. Both are difficult to manage with current treatment options.

However, The Independent did correctly cover the results of this latest study.

 

What kind of research was this?

This was a cross-sectional survey of people with a diagnosis of PoTS and people with CFS.

The aim was to raise awareness of PoTS in health professionals, and to see if there were any differences between people with PoTS seen in one centre, compared to those who were members of the largest UK support group for people with PoTS – PoTS UK.

The researchers compared all of these people with PoTS to people with CFS who did not have PoTS. A previous cross-sectional study in 2008 found that 27% of those with a diagnosis of CFS also had PoTS.

 

What did the research involve?

The researchers sent questionnaires to:

  • people diagnosed with PoTS who had attended their clinics
  • all members of the support group PoTS UK 
  • people with CFS without PoTS

The researchers looked for differences in demographics, time taken for a diagnosis to be made, symptoms and treatments. The participants with PoTS were asked to complete two initial questionnaires about:

  • background details, including education level, age of symptom onset, age at diagnosis of PoTS and current medication
  • symptoms of PoTS, potential precipitants to the illness and any other illnesses

All of the participants, those with PoTS and those with CFS, were sent the following six validated symptom assessment tools:

  • fatigue impact scale
  • Epworth sleepiness scale
  • orthostatic grading scale
  • hospital anxiety and depression scale
  • patient-reported outcomes measurement information system, health assessment questionnaire (PHAQ)
  • cognitive failures questionnaire

 

What were the basic results?

The researchers recruited 136 people with PoTS (52 out of 87 from the clinics and 84 of the 170 members of PoTS UK).

The researchers found that patients with PoTS are predominantly women, young, well-educated and have significant and debilitating symptoms that considerably impact a person's quality of life.

The researchers noted several differences between their cohort of patients and all members of the support group. There were differences in:

  • age
  • gender
  • employment
  • working hours

20% of the total sample of people with PoTS also had a diagnosis of CFS (27 out of the 136 participants), and this went up to 42% in those recruited from the clinic (22 out of 52). Of people with PoTS who did not report CFS, 43% of them would have met the diagnostic criteria.

Compared to those with both PoTS and CFS, people diagnosed only with PoTS:

  • had significantly more symptoms before diagnosis, the majority of which were palpitations, dizziness, memory impairment, breathlessness, lightheadedness and muscle aches
  • were more likely to receive disability benefits

The researchers also compared people with PoTS to people who had CFS. It is not known how many people with CFS completed the questionnaires, but the study reports that they were matched to the people with PoTS in terms of age and gender.

Comparing all people with PoTS (with and without CFS) to people with just CFS, it was found that:

  • there were similar high levels of symptom burden in each group
  • the symptoms related to low blood pressure, such as dizziness, were more severe in the PoTS group
  • anxiety and depression scores were significantly higher in the CFS group

On analysing the questionnaire responses from people with PoTS, the researchers found that:

  • there were 21 different treatment “regimes” for PoTS
  • the most common treatment was beta-blockers
  • 27% of people were receiving no treatment for their PoTS
  • there was no difference in fatigue severity, daytime sleepiness, cognitive or autonomic symptoms or level of functional impairment between those being treated and those having no treatment
  • people without medication scored slightly higher on the anxiety and depression scale

 

How did the researchers interpret the results?

The researchers concluded that postural tachycardia syndrome (PoTS) “is a condition that is associated with significant symptoms that impact on quality of life. Currently, there are no evidence-based treatments for PoTS, and its underlying pathogenesis [reason for disease development], natural history and associated features are not fully understood.

“We would suggest that increasing awareness of this debilitating disease is important to improve understanding, diagnosis and management of PoTS”.

 

Conclusion

This study has described some of the demographics and symptoms of people with PoTS and has also shown that there is a degree of overlap in people diagnosed with CFS and PoTS.

However, in contrast to the media's coverage, this study does not show whether patients were misdiagnosed. It also does not show that there are effective treatments for PoTS. In fact, very little difference was found in symptoms between people having treatment compared to those that were having none.

There are several other limitations to this study. These were the fact that:

  • it was based on a small number of participants
  • there was a low response rate to the questionnaires, which could bias results, either because people were too ill to respond or were too busy
  • it is unclear how well people with PoTS were matched to people with CFS; 20% of the people with PoTS also had a diagnosis of CFS, which would compromise the results

However, the researchers set out to raise awareness of PoTS in health professionals. This was done to increase its recognition, so that further research can be conducted in order to improve treatment options, which from the media coverage garnered, they have almost certainly achieved.

Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

Little-known heart condition found affecting mostly educated young women. The Independent, June 17 2014

Third of ME cases 'wrongly diagnosed': Experts says thousands thought to have chronic fatigue actually have similar condition that can be treated. Mail Online, June 17 2014

ME: one third of patients wrongly diagnosed. The Daily Telegraph, June 17 2014

Links To Science

McDonald C. et al. Postural tachycardia syndrome is associated with significant symptoms and functional impairment predominantly affecting young women: a UK perspective. BMJ Open. Published June 16 2014

Categories: Medical News

Warning issued over washing raw chicken

Medical News - Mon, 06/16/2014 - 14:30

"Don't wash chicken before cooking it, warns Food Standards Agency," The Guardian reports. The Food Standards Agency (FSA) has issued the advice as many people do not realise that washing raw poultry can spread bacteria, leading to an increased risk of food poisoning.

The bacteria in question, campylobacter, is the most common cause of food poisoning in the world and affects about 280,000 people in the UK each year.

New guidance is intended to remind people that washing raw chicken before cooking increases the likelihood of infection through splashing the bacteria on to work surfaces, clothing and cooking equipment. This is known as cross-contamination.

Washing is therefore not recommended – it is also unnecessary as thorough cooking will kill any bacteria.

 

Who has issued the advice?

The Food Standards Agency (FSA) has issued the guidance, which coincides with the start of this year's Food Safety Week. The FSA is the government department responsible for food safety and food hygiene across the UK.

They are trying to raise awareness of campylobacter infection because a survey of around 7,000 people found that while more than 90% of the public have heard of food poisoning from salmonella and E. coli, only 28% had heard of campylobacter. In fact, campylobacter causes more food poisoning than all the other major causes put together.

 

What is the advice?

The FSA is asking people to stop washing chicken before cooking it to reduce the incidence of campylobacter. The advice itself is not new, but the call has been issued after a survey found that 44% of people still wash chicken before cooking.

Other measures that are being taken by the FSA include:

  • working with farmers and producers to minimise the rates of campylobacter in chickens
  • minimising the levels of contamination in slaughterhouses and processors
  • ensuring caterers use preventative measures to reduce the risk of infection
  • asking TV production companies to ensure that programmes do not show anyone washing raw chicken

In addition, the major supermarkets have agreed to:

  • provide clearer information on their packs of raw chicken and turkey
  • have features on campylobacter in their magazines

 

What are the symptoms of campylobacter infection?

The typical symptoms are abdominal pain and diarrhoea, which occurs two to five days after infection.

The diarrhoea can sometimes contain blood. Other symptoms of campylobacter infection can include fever, headache, nausea and vomiting. It usually lasts for three to six days.

 

What are the potential dangers of campylobacter?

Campylobacter infection can be fatal in young children, the elderly and people who have a lowered immune system. Lowered immunity can occur as a result of health conditions such as HIV, or as a side effect of certain treatments, such as chemotherapy.

Complications of the infection include:

 

When should I seek medical advice for suspected food poisoning?

Most cases of food poisoning do not require medical treatment. However, you should seek medical advice if you have any of the following signs or symptoms:

  • vomiting that lasts more than two days
  • you are unable to keep liquids down for more than a day
  • diarrhoea that lasts for more than three days
  • blood in your vomit
  • blood in your stools
  • seizures (fits)
  • changes in your mental state, such as confusion
  • double vision
  • slurred speech
  • signs of severe dehydration, such as a dry mouth, sunken eyes, and an inability to pass urine, or passing small amounts of dark, strong-smelling urine

Always contact your GP if you get food poisoning during pregnancy. Extra precautions may be needed.

 

What is the best way to prepare raw chicken?

The FSA advises the public to:

  • cover and chill raw chicken
  • not wash raw chicken
  • wash used utensils
  • cook chicken thoroughly

Other measures that will reduce the risk of infection include:

  • washing hands with soap and warm water before cooking, after touching raw food, after touching the bin, and after going to the toilet
  • keeping raw food away from ready-to-eat foods
  • using different chopping boards for raw and ready-to-eat foods
  • keeping raw meat in a clean, sealed container on the bottom shelf of the fridge so it cannot drip on other foods

Read more advice about food safety.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Don't wash chicken before cooking it, warns Food Standards Agency. The Guardian, June 16 2014

Washing chicken 'spreads infection'. BBC News, June 16 2014

Should I wash raw chicken? Experts say no as new deadly bug is found. Daily Mirror, June 16 2014

Don't wash chicken before cooking, new guidance warns. The Daily Telegraph, June 16 2014

Don't wash chicken ...it splashes bugs all over the kitchen: Health experts' warning over food poisoning. Daily Mail, June 16 2014

Washing raw chicken 'can cause food poisoning,' Food Standards Agency warns. The Independent, June 16 2014

Washing raw chicken 'increases chances of food poisoning'. Metro, June 16 2014

Stop washing raw chicken, experts warn. ITV News, June 16 2014

Categories: Medical News

'Bionic' pancreas could be used to treat diabetes

Medical News - Mon, 06/16/2014 - 14:00

“An artificial pancreas could allow thousands of diabetes patients to live normal lives,” the Mail Online reports.

People with type 1 diabetes require lifelong insulin, as their body does not produce any. Insulin is a hormone that plays a key role in regulating the body’s blood sugar levels.

In a new study, the safety and effectiveness of a “closed-loop” insulin delivery system has been assessed.

Compared to a standard insulin pump, where the insulin delivery is programmed, the closed-loop system continuously measures sugar levels and automatically makes fine adjustments to insulin delivery in response. In effect, it acts like an artificial pancreas.

It can be challenging trying to keep insulin delivery at the right level in order to control blood sugar levels within the normal range, while avoiding blood sugar becoming too low (hypoglycaemia), particularly overnight.

The device improved blood sugar control overnight – importantly, it was not associated with hypoglycaemic episodes.

However, one of the trial’s limitations was its small size. In addition to this, it only examined the effects of the overnight closed-loop system compared with the standard pump over four periods of four weeks each. Longer-term studies examining the safety and effectiveness of this system in larger numbers of people with type 1 diabetes are now needed.

 

Where did the story come from?

The study was carried out by researchers from the Universities of Cambridge, Sheffield and Southampton, and King’s College London. It was funded by Diabetes UK.

The study was published in the peer-reviewed medical journal The Lancet.

While the Mail Online’s reporting of the study is broadly accurate, its headline: “Artificial pancreas could help stem the diabetes epidemic: Device could help patients lead normal lives by stopping need for constant insulin” is potentially misleading on multiple levels.

Firstly, “artificial pancreas” could be misinterpreted to mean that this is an artificial organ that is surgically transplanted into the person and can produce insulin to take the place of their own pancreas. In reality, the “closed-loop” insulin delivery system is designed to be worn outside of the body.

Secondly, the “diabetes epidemic” is usually taken to mean type 2 diabetes, which is associated with lifestyle factors such as being obese and lack of exercise. It is true that some people with type 2 diabetes can go on to need insulin; however, this particular study looked at people with type 1 diabetes.

The rise of people with type 2 diabetes can rightly be described as an “epidemic”. In contrast, the number of people who develop type 1 diabetes (which usually starts during childhood) in any given year has remained relatively static (around 24 in every 100,000 children).

Neither would this treatment “stem” the number of new cases of either type of diabetes.

Thirdly, the Mail says the treatment would “stop need for constant insulin”, which is not the case. In fact, this overnight closed-loop system delivers constant insulin. It has also only been used overnight, meaning the person continued delivering their insulin as normal during the day.

 

What kind of research was this?

This was a randomised crossover trial that aimed to see whether the use of a novel overnight insulin delivery system would help to improve blood glucose (sugar) control in people with type 1 diabetes.

Type 1 diabetes is an autoimmune condition where the body starts to produce antibodies that attack and destroy the insulin-producing cells in the pancreas. The body can therefore not make insulin, so the person relies on lifelong insulin injections to control their blood sugar. Type 1 diabetes most commonly develops in childhood.

It is different from type 2 diabetes, which is where the pancreas still produces insulin, but it either cannot produce enough, or the cells of the body are no longer sensitive enough to the actions of insulin to adequately control blood sugar. Type 2 diabetes is usually controlled by diet and medication, though some people with poor control also end up needing insulin injections, similar to people with type 1 diabetes.

As the researchers say, one of the main challenges with type 1 diabetes is keeping the right level of blood sugar control; people with this condition can face the challenge of complex daily insulin regimens and regular blood sugar monitoring.

One of the most common risks is when the blood sugar becomes very low (hypoglycaemia), which can cause varied symptoms, including agitation, confusion and altered behaviour, progressing to loss of consciousness. Hypoglycaemic episodes can often occur at night and after drinking alcohol, making it a particular risk for young people with diabetes.

This study was looking at an overnight “closed-loop” insulin delivery system – in other words, an artificial pancreas.

A small device is connected to the body through a standard insulin pump, and this delivers insulin under the skin without the need for continuous injections.

The wearer adjusts and programmes the amount of insulin to be delivered, according to their blood sugar levels.

The closed-loop system is different: a real-time sensor continuously monitors the person’s sugar level (by measuring the level in the interstitial fluid that surrounds body cells) overnight and then automatically increases or decreases insulin delivery in response to this, as would normally happen in the human body with a healthy pancreas.

Studies to date have suggested that the system is a safe and feasible option, and decreases the risk of hypoglycaemia.

This crossover randomised controlled trial aimed to see whether four weeks of unsupervised use of the overnight closed-loop system would improve blood sugar control in adults with type 1 diabetes.

The crossover design meant that the participants acted as their own controls, first receiving insulin with the closed-loop system or a standard insulin pump (control), then swapping over to the other group.

 

What did the research involve?

The study recruited 25 adults (18 years or over, with an average age of 43) with type 1 diabetes, who were used to using an insulin pump, monitoring their blood sugar and self-adjusting their insulin.

All participants first took part in a two to four week run-in period, where they were trained in the use of the insulin pumps and continuous sugar monitoring, and their treatment was optimised.

The trial was then divided into two subsequent four-week treatment periods, with a three to four week wash-out period in between, when they continued with their normal diabetes care regimen.

In the two treatment periods, the participants received continuous sugar monitoring and were randomly assigned to receive overnight insulin delivery with either the closed-loop system or a standard insulin pump (control).

The study was open-label meaning that participants and researchers knew what system was being used.

The participants received the treatment unsupervised and at home, though they stayed in the research clinic for the first night that they used the closed-loop system.

They were instructed to start the closed-loop system at home after their evening meal and discontinue it before breakfast the next morning.

The closed-loop system calculates a new insulin infusion rate every 12 minutes in response to the monitored glucose level.

The primary outcome examined was the time the person spent in the target optimum sugar range (3.9 to 8.0mmol/l) between midnight and seven in the morning.

Of the 25 people randomised, one person withdrew from the study, meaning that only 24 were available for analysis.

 

What were the basic results?

The time that participants spent in the target optimum sugar range during the seven-hour overnight period was higher when using the closed-loop system (52.6% of the time) compared to when they used the control pump (39.1%), with a significant difference of 13.5%.

The closed-loop system improved time spent in the target range in all but three participants. It also reduced the average overnight sugar level and the time spent above the target range, without increasing the time spent with a hypoglycaemic sugar level. The time spent with hypoglycaemia overnight (less than 3.9mml/l) was no different with the closed-loop and standard insulin pumps. The closed-loop system was found to deliver 30% more insulin during the night than the standard insulin pump.

There was no difference to total daily insulin delivery. However, when examining the full 24-hour period, when participants used the closed-loop system overnight their 24-hour blood sugar level was significantly reduced (by 0.5mmol/l), and their time spent within the target range was increased. People were also observed to have significantly lower levels of HbA1c (glycated haemoglobin – a longer-term indicator of blood sugar control over the past weeks to months).

There were no severe adverse effects associated with using the closed-loop system.

 

How did the researchers interpret the results?

The researchers conclude that “unsupervised overnight closed-loop insulin delivery at home is feasible and could improve [blood sugar] control in adults with type 1 diabetes”.

 

Conclusion

It can be a challenge for people with type 1 diabetes to keep insulin delivery at the right level, which is necessary to keep blood sugar levels within the normal range. Avoiding periods of hypoglycaemia can be a challenge, particularly overnight.

A further challenge is that the symptoms of type 1 diabetes usually develop during childhood. This means that children, especially teenagers, can often find the need to stick to a particular treatment “regime” and regularly monitor their blood sugar quite restrictive. However, without such treatment recommendations, they can be at risk of complications, such as hypoglycaemia.

Because of this difficulty, a device to help simplify the treatment of type 1 diabetes would be welcomed.

The device in question, the closed loop insulin delivery system, automatically makes fine adjustments to insulin delivery in response to the glucose level being continuously measured.

This crossover randomised controlled trial demonstrated that the closed-loop system improved blood sugar control overnight.

Though the closed-loop system was only used overnight, the effects also extended into the day, significantly reducing their 24-hour sugar level.

Importantly, it was not associated with hypoglycaemic episodes.

This study is also said to be the first to monitor safety and effectiveness of the closed-loop system when used unsupervised in the person’s own home over a four-week period. The participants continued all their daily activities and dietary patterns as normal during the study period, thereby assessing the system in a real-life situation without additional restrictions placed on the person.

However, there are some limitations, most notably the small sample size of only 25 participants. In addition to this, though the study period was fairly long, at four weeks, it was not long enough to monitor longer-term effects.

In particular, as the researchers acknowledge, though they monitored HbA1c, that shows the blood sugar control during the lifetime of the red blood cell, which is around four months, rather than four weeks.

This means that the short study design cannot reliably indicate whether closed-loop monitoring would have influenced longer-term blood sugar control as indicated by HbA1c.

A further limitation is that the technique was only used at night, between midnight and 7am, when each participant was resting/sleeping. It is unclear whether the technique would be responsive enough to cope with daytime activities that require greater adjustment of insulin control, such as eating and exercise.

Therefore, unfortunately, an insulin delivery system that would completely remove any need for the person to monitor their blood sugar or adjust their own insulin does not seem to be on the cards, at least for the immediate future. 

Despite these limitations, the results of this small study are encouraging. Studies involving a greater number of people and taking place over a longer duration are now required.

Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

Artificial pancreas could help stem the diabetes epidemic: Device could help patients lead normal lives by stopping need for constant insulin. Mail Online, June 16 2014

Links To Science

Thabit H, Lubina-Solomon A, Stadler M, et al. Home use of closed-loop insulin delivery for overnight glucose control in adults with type 1 diabetes: a 4-week, multicentre, randomised crossover study. The Lancet Diabetes and Endocrinology. Published online June 16 2014

Categories: Medical News

Are 'career girl' lifestyle abortions on the rise?

Medical News - Fri, 06/13/2014 - 12:39

Media sources have reported on the "career girl" abortion (Daily Mail) or "lifestyle" abortion (The Daily Telegraph) after figures released by the Department of Health showed that increasing numbers of women aged 25 to 29, or who have long-term partners or children already, are having abortions.

The media stories follow the release of government abortion statistics in England and Wales for 2013. This provides information on abortion (medically known as "termination of pregnancy") rates and characteristics about the women having abortions.

While the total number of abortions in England and Wales has increased, the rate of abortions has actually decreased. And encouragingly, rates among teenagers have fallen. The highest abortion rate is now among those aged 22 in 2013 (up from 21 in 2012).

The Department of Health report provides us with facts only, not explanations. It does not discuss the possibilities for the changes in trends seen, and all media reports of "career girl" or "lifestyle" abortions suggesting abortion is sometimes used as a method of contraception are pure speculation only, with no foundation in this report.

 

What do the statistics show?

Any doctor performing an abortion is legally required to notify the chief medical officers (CMOs) within 14 days of the abortion. The statistics in this Department of Health report come from abortion notification forms returned to the CMOs of England and Wales, and can therefore be considered reliable.

The total number of abortions in 2013 was 185,331, an increase of 0.1% on 2012 (185,122) and a 2.1% rise from 2003 (181,582). But despite the increase in the overall number of abortions, rates among women have actually decreased.

The age-standardised abortion rate was 15.9 per 1,000 women aged between 15 and 44 years old resident in England and Wales. This was 0.8% lower than in 2012 and 4.7% lower than in 2003 (16.7). It is the lowest abortion rate for 16 years.

However, the age group with the highest abortion rate seems to be getting older. In 2013, it was highest for women aged 22 (at 30 per 1,000 women). The previous year, it was highest for women aged 21 (at 31 per 1,000).

Teenage abortion rates in 2013

The abortion rates among the teenage population are lower and have been falling: in 2013, the rate among under-16s was 2.6 per 1,000, and the rate among under-18s was 11.7 per 1,000.

These figures are both lower than the previous year (3.0 and 12.8 per 1,000 respectively) and 10 years ago (3.9 and 18.2 per 1,000 respectively).

 

What are the reasons for these abortions?

As the Department of Health report states, the Abortion Act 1967 permits the termination of a pregnancy (abortion) by a registered medical practitioner subject to certain conditions.

A legally induced abortion must be certified by two registered medical practitioners and is carried out on the grounds of one of five reasons (A to E):

  • A: risk to the life of the woman if the pregnancy is continued
  • B: risk of serious permanent injury to the physical or mental health of the woman
  • C: risk of injury to the physical or mental health of the woman (and the pregnancy had not exceeded its 24th week)
  • D: risk to the physical or mental health of any existing children in the family (and the pregnancy had not exceeded its 24th week)
  • E: risk that the child would be born with physical or mental abnormalities such that they would be seriously handicapped

Most abortions related to unwanted or unplanned pregnancy will usually be carried out on grounds C or, rarely, grounds D (for example, if the woman has other children who she feels she wouldn't be able to care for adequately if she had another).

As the report demonstrated, in 2013 97% of abortions (180,680) were carried out on grounds C. Virtually all of these (99.8%) were carried out specifically on the grounds of threat to the woman's mental health, rather than her physical health.

Meanwhile, only 1% of abortions in 2013 were carried out on grounds E – that the child would be born disabled. Nearly half of the 2,732 abortions carried out on grounds E were because of identified congenital abnormalities, a third of these being caused by chromosomal abnormalities (most commonly, Down's syndrome).

 

Where do the media reports of 'career girl abortions' come from?

The study reported varied information about the lifestyle characteristics of women undergoing abortion in 2013. The media has made sweeping statements about women's motivations and needs for abortion loosely based on these findings.

Facts that may have influenced the headlines include:

  • Most abortions (81%) were carried out for single women, a proportion that has risen since 2003 (76%). More than 60% of these "single" women were reported to be with a partner. Sixteen percent of women having an abortion were reported to be married or in a civil partnership.
  • Just over a third of women (37%) having an abortion had had one or more previous abortions. The number of women this applied to increased with age, for obvious reasons: 18% of women aged 18 or 19 had had one or more previous abortions, increasing to 34% of 20-24 year olds, 44% of 25-29 year olds, and 47% of 30-34 year olds, and 45% of those over 35.
  • Just over half of women (53%) undergoing abortion had had previous pregnancy resulting in birth, while 18% had had previous pregnancy resulting in miscarriage.
  • Presumably the most important factor influencing the tone of the headlines was the finding that 43,578 women aged between 25 and 29 had an abortion in 2013, compared with 41,882 in 2012. The number of women who had an abortion who had previously given birth in this age group increased from 52% in 2012 to 53% in 2013.

However, the report provides figures only. The Department of Health report does not discuss possibilities for changes in trends, and all media reports of "career girl" or "lifestyle" abortions suggesting abortion is sometimes used as a method of contraception are pure speculation, with no foundation in this report.

As the figures show, while the total number of abortions in England and Wales has increased, the rate per 1,000 women has actually decreased.

Teen pregnancy rates have also fallen, which is encouraging. The reason for this decrease is not known – it could be the result of improved sexual health awareness and education, but again this is pure speculation.

The fact that the number of women who have had previous abortions increases with age group is, as the report says, likely just a result of increasing age increasing the exposure time for possible pregnancy.

The information on the proportion of women having an abortion who are single, with a partner or married similarly tells us little about women's lifestyle choices.

Overall, the report only provides us with facts, not explanations.

 

Where can I get advice on abortion and pregnancy?

You can get help and advice on contraception, pregnancy and abortion from various sources, including your GP or local sexual health clinic.

Online support services include FPA and Brook, or you can call the sexual health advice line on 0300 123 7123.

 

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

'Lifestyle' abortions warning as serial termination numbers surge. The Daily Telegraph, June 12 2014

Rise of the 'career girl' abortion: Number of women aged 25 to 29 having abortions increases by 20% in a decade. Daily Mail, June 12 2014

Links To Science

Department of Health Abortion Statistics, England and Wales: 2013 (PDF, 2.83Mb). Published June 12 2014

Categories: Medical News

Hip replacement cement linked with deaths

Medical News - Fri, 06/13/2014 - 12:39

"Toxic NHS hip implants blamed for more than 40 deaths," The Daily Telegraph reports. Other media sources similarly report how surgical "cement" used in some hip replacements has been linked to the deaths.

This news is based on a study looking at risk of death or severe harm associated with partial hip replacements involving cement for people with a fracture at the top of the thigh bone (fractured neck of femur).

The practice of using cement to attach the replacement "ball" joint to the "socket" is a clinical decision made by surgeons based on their experience and the patient's characteristics.

In 2009, the National Patient Safety Agency (NPSA) alerted health professionals to the risk of bone cement implantation syndrome (BCIS), which can happen when cement is used.

In BCIS, insertion of cement somehow leads to some fat and bone marrow contents being released into the bloodstream (venous embolisation). This in turn risks blocking the blood flow, potentially causing respiratory and cardiac arrest.

This study looked at the number of cases of BCIS reported between 2005 and 2012. There were 62 cases of death or severe harm caused by BCIS in this period. This is 1 case per every 2,900 partial hip replacements for fractured neck of femur.

Worryingly, three-quarters of these incidents occurred after 2009, suggesting that the precautionary measures regarding use of cement advised by the NPSA had either not been implemented or were not effective.

However, this study is not able to fully appraise the risks and benefits of using cement or not.

 

Where did the story come from?

The study was carried out by researchers from Imperial College London, including Sir Liam Donaldson, the former chief medical officer.

It is reported to be part of a research programme at Imperial College funded by National Health Service (NHS) England to develop incident reporting in the NHS.

The study has been published in the peer-reviewed medical journal BMJ Open and is open access, so it is freely available to read online.

The Daily Telegraph's headline "Toxic NHS hip implants blamed for more than 40 deaths" has somewhat misfired. It is not the implants themselves that have been called into question, but the cement used to hold them in place. The cement is not made by the NHS, and it is almost certain that similar practices are used in the UK private sector, as well as healthcare systems in other countries.

Once past the headlines, the media is representative of this research, although The Telegraph included a response from NHS England, while The Guardian and The Independent chose to take the researchers' words at face value.

This is not the first time there have been concerns about hip replacements. In 2012, some brands of metal-on-metal hip implants were recalled over safety concerns.

 

What kind of research was this?

This was a patient safety surveillance study that aimed to estimate the risk of death or severe harm in people undergoing partial hip replacement surgery for a fracture at the top of the thigh bone (fractured neck of femur).

A partial hip replacement (hemiarthroplasty) involves replacing only the top "ball" part of the thigh bone that is fractured, as opposed to a total hip replacement (often carried out because of osteoarthritis, for example), which involves replacing the "socket" part of the joint as well.

Around 75,000 fractures to the neck of femur are said to occur in the UK every year – most are related to osteoporosis. The researchers report that in 2012, 22,000 people in the UK received a partial hip replacement following fracture.

In these operations, cement is often used to hold the replacement metal "ball" in place in the socket, but there is considerable debate about this practice.

An alternative is to not use cement and allow the bone of the socket to gradually mesh with the replacement.

The decision to use cement or not usually comes down to the surgeon's choice and the characteristics of the patient.

In 2009, the National Patient Safety Agency (NPSA) accumulated an increasing number of reports attributing the cement used in partial hip replacements to severe harm and sudden death.

The specific concern – bone cement implantation syndrome (BCIS) – is said to be caused by the cementation process somehow leading to some fat and bone marrow contents being released into the venous bloodstream (venous embolisation).

This in turn can potentially cause blockages in the bloodstream, leading to low blood pressure and respiratory and cardiac arrest. The exact way that cementation may cause this to happen is poorly understood.

The identified clusters of incidents led to guidance being given to health professionals about additional precautions for the use of cement (related to patient assessment, anaesthetic technique and surgical technique). However, as the researchers say, there was no firm direction about whether to use cement or not.

Since the alert, further research studies have looked into the number of incidents reported. The current study examines the number of incidents of BCIS reported to the National Reporting and Learning System (NRLS), a patient safety incident and reporting system set up by the NHS in 2003.

 

What did the research involve?

The researchers looked for all incidents reported by NHS hospitals in England and Wales between January 2005 and December 2012 where the incident report clearly described severe patient harm associated with cement use in partial hip replacement for fractured neck of femur.

To identify potential cases, the researchers looked for key words in the report text, such as "cement" and "[death during the operation]", "cardiac arrest", "[low blood pressure]", "fat embolus", or "collapse", and words related to orthopedics and hip replacement surgery.

They specifically looked for reports classified as "death", "severe harm" or "moderate harm". The identified incidents were then separately reviewed and verified by two researchers.

The main outcomes the researchers were interested in were the number of reported deaths, cardiac arrests and near cardiac arrests per year. They also looked at the timing of the patient's deterioration and its relation to cement insertion.

They specifically looked at the number of reports that occurred before and after the 2009 NPSA alert on the potential risk of cement was issued.

 

What were the basic results?

Over the seven-year period, there were 360 identified potential reports, of which 62 were judged by the two reviewers to clearly report severe harm or death specifically associated with the use of cement in partial hip replacement for fractured neck of femur.

Of these 62 incidents:

  • two-thirds (41 of 62) were deaths, of which most (33) occurred on the operating table
  • 14 involved a cardiac arrest from which the person was resuscitated
  • 7 involved near cardiac arrests from which the person recovered

In the majority of cases (55/62, 89%) the person deteriorated during or within a few minutes of cement insertion.

Overall, there was one incident of BCIS for every 2,900 partial hip replacements for fractured neck of femur carried out over the seven-year period. There was a general increase in the number of incidents reported every year between 2005 and 2012. Nearly three times as many incidents were reported after the NPSA alert was issued in 2009 compared with before.

 

How did the researchers interpret the results?

The researchers conclude that the incident reports identified provide evidence that cement use in partial hip replacement for fractured neck of femur in England and Wales can be associated with death or severe harm as a result of BCIS.

They note that three-quarters of the deaths identified have occurred since the 2009 alert, when the NPSA publicised the issue and encouraged the use of mitigation measures related to patient assessment, anaesthetic technique and surgical techniques.

The researchers suggest that the reports show that there has been incomplete implementation or effectiveness of these mitigation measures.

They go on to say that there is a need for stronger evidence that weighs the risks and benefits of cement in partial hip replacement for fractured neck of femur.

 

Conclusion

This is valuable research that highlights that there have been 62 cases of severe patient harm or death between 2005 and 2012 as a result of cement use in partial hip replacement for fractured neck of femur resulting in bone cement implantation syndrome (BCIS).

Notably, the 2009 alert by the National Patient Safety Agency (NPSA) on the potential for this risk doesn't appear to have had an effect on decreasing the number of cases. In fact, the number of cases clearly increased year by year over the seven-year study period.

The reason for the apparent ineffectiveness of the alert is not known. The researchers can't say whether the suggested measures related to patient assessment, anaesthetic technique and surgical techniques have not been taken up by professionals, or have just not been effective.

It is also possible that an increased awareness of the risk of BCIS after the NPSA alert led to more serious harms and deaths being reported as potentially associated with cement use.

As the researchers further acknowledge, it could be that the incidence of 1 in every 2,900 partial hip replacements for fractured neck of femur could even be an underestimate, as there may have been a lack of reporting to the National Reporting and Learning System (NRLS) that was used to provide the data for this study.

Also, as the researchers say, this study of reported incidents is not able to fully appraise the benefits and risks of cement use in partial hip replacements, so its findings need to be considered alongside information on the use of cement collected through other sources.

Professor Sir Liam Donaldson, former chief medical officer and a patient safety enthusiast, was involved in this study, and is quoted in The Telegraph as saying: "We want to see this whole question about the use of cement opened up again and further research and evaluation of the risks."

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Toxic NHS hip implants blamed for more than 40 deaths. The Daily Telegraph, June 13 2014

Cement used in hip replacement linked to surgery deaths. The Independent, June 13 2014

Use of cement in hip replacements questioned by researchers. The Guardian, June 13 2014

Links To Science

Rutter PD, et al. What is the risk of death or severe harm due to bone cement implantation syndrome among patients undergoing hip hemiarthroplasty for fractured neck of femur? A patient safety surveillance study. BMJ Open. Published online June 12 2014

Categories: Medical News

'Super-mums' at risk of depression

Medical News - Thu, 06/12/2014 - 15:00

“’Super-mums’ … may be more likely to suffer from depression, researchers say,” the Mail Online reports. A US study found a possible association between concern about being perceived as a perfect parent and maternal depression risk.

The researchers developed a 26-item questionnaire designed to assess what they described as “rigidity of maternal beliefs scale” (RMDS).

Women with a high RMDS score had very fixed notions about the role of motherhood and the responsibilities it brings.

For example, they agreed strongly with statements such as “I should do everything for my baby myself” and “Having negative thoughts about my baby means something is wrong with me”. Though these types of beliefs are unlikely to match the messy reality of bringing up a baby.

The researchers did find that women with a high RMDS store had an increased tendency to develop postnatal depression.

This was a small study but the thinking underpinning it seems plausible. Mothers who assume that motherhood is always going to be joyous may be more likely to end up depressed when they are confronted with the reality of the situation.

Having a baby is certainly joyful but it is never easy. It’s important new parents feel they can call on others for support – rather than believing they must do everything themselves.

 

Where did the story come from?

The study was carried out by researchers from the University of Michigan, Florida State University and was funded by the University of Michigan.

The study was published in the peer-reviewed journal Depression and Anxiety.

It was covered fairly if in rather loose terms by the Mail Online.

The site did not explain the study’s aim – to design and test a measure of women’s beliefs and how these are related to postnatal depression.

 

What kind of research was this?

The researchers say that perinatal (or postnatal) depression has a negative impact on women, parenting and children’s development. Yet little is known about how far maternal beliefs or attitudes are associated with depression.

They suggest that “rigid” beliefs such as believing you must “fix” all parenting difficulties yourself may be associated with lower mood during the postnatal period.

Their aim here was to create and test a questionnaire for pregnant women and new mothers, examining their beliefs in three areas closely related to mood and behaviour:

  • whether a mother thinks she is competent (maternal self-efficacy)
  • whether she believes babies get hurt or sick easily (perceptions of child vulnerability)
  • whether she internalises societal beliefs about what good mothers should do and feel (perceptions of societal expectations)

They then aimed to test whether the results from the questionnaire could identify women at risk of postnatal depression.

 

What did the research involve?

The researchers initially developed a 30 item measure, called the Rigidity of Maternal Beliefs Scale (RMBS). They did this after consulting with expert clinicians and researchers in the field of women’s mental health and conducting a review of the existing literature, as well as interviewing depressed women.

They also created a seven point answer scale, ranging from 1 (strongly disagree) to 7 (strongly agree), with high scores suggesting more rigid beliefs and lower scores more flexibility.

After piloting the measure with a small group of depressed women, they removed six of the items, resulting in 26 final items.

The RMBS was designed to cover four, inter-related, areas of belief:

  • perceptions of societal expectations of mothers – beliefs about the responsibilities of motherhood – such as “I should do everything for my baby myself” and “I should be able to figure out and fix parenting difficulties myself”
  • role identity – beliefs about the experience of motherhood, such as “being a mother should be positive” and “babies get hurt or sick easily”
  • maternal confidence – how confident (or not) they feel about being a mother and how this level of confidence compares to other mothers
  • maternal dichotomy – beliefs about what makes a “good” or “bad” parent, both in terms of individual thinking and how others perceive them, such as “if my baby misbehaves, then others will think I am a bad parent”

The questionnaire was sent out to women twice – once during pregnancy and again, after the baby’s birth.

The women were also asked to complete a validated questionnaire to assess depressive symptoms.

They were also asked to fill out a further, eight item self-report questionnaire, called the parenting sense of competence scale (PSOC).

Women were eligible to participate in the study if they were pregnant, over the age of 18, fluent in English, and had no adoption plan. The prenatal questionnaires were mailed out to 273 women who met the criteria, 134 women returned the questionnaires, giving a response rate of 49%. Of those, 113 women (84%) also returned postnatal questionnaires, participating at both study time points.

They analysed the results, looking at women’s scores on the new measure, their scores on the parental competence scale and their scores on the depression scale.

 

What were the basic results?

The researchers found their 24 item scale was a reliable, valid measure for predicting postnatal depression. Women who scored higher on the Rigidity of Maternal Beliefs Scale were associated with a higher risk of developing postnatal depression.

They found that such a questionnaire could be divided into four areas reflecting a mother’s Perception of Society’s Expectations, Role Identity, Maternal Confidence and Maternal Dichotomy (mothers’ belief they are categorised into “good” and “bad” based on how their child behaves).

 

How did the researchers interpret the results?

They say their results suggest that the RMBS could be used as a valid, reliable measure to examine these areas of maternal beliefs, and to identify those at risk of postnatal depression. They argue that the RMBS should now be tested on a larger, more diverse sample of women.

 

Conclusion

This was a small study of relatively highly educated, high income women, most of them with partners, so whether its findings are generalizable to all new mothers is uncertain.

The study did not take account of stressful events which can adversely affect mental health such as relationship or financial difficulties.

Still, many experts agree with the thinking underpinning the study.

Having unrealistic beliefs and expectations about the experience of motherhood could make a woman more vulnerable to depression if she is unable to come to terms with the reality of the situation; especially if she does not seek help and support from others.

Having a baby can bring great joy but with that joy can come an immense amount of stress which can trigger depression. As one expert in the field put it “I’m not surprised that some mothers develop depression. What surprises me is that all mothers don’t develop depression.”

If you are concerned about your mood you should ask yourself two questions:

  • During the past month, have you often been bothered by feeling down, depressed or hopeless?
  • During the past month, have you often been bothered by taking little or no pleasure in doing things that normally make you happy?

If the answer to either of these is yes, then it is possible you have postnatal depression. You should contact your GP for advice.

 Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

'Super-mums' who worry about being the perfect parent are more likely to develop depression, experts claim. Mail Online, June 12 2014 

Links To Science

Thomason E, Flynn HA, Himle JA, Volling BL. Are women's parenting-specific beliefs associated with depressive symptoms in the perinatal period? Development of the rigidity of maternal beliefs scale. Depression and Anxiety. Published online May 29 2014

Categories: Medical News

High-factor sunscreen doesn’t cut melanoma risk

Medical News - Thu, 06/12/2014 - 14:00

“High-factor sun cream cannot…protect against the deadliest form of skin cancer,” The Guardian reports. Research involving mice with a predisposition to develop melanoma found that sunscreen only delayed, rather than prevented, the onset of melanoma.

Malignant melanoma occurs when cells that produce melanin – pigment that darkens the skin – rapidly divide and grow uncontrollably.

A mutation in a gene crucial for cell growth, BRAF, has been found in several cancers, including around half of melanoma cases. Mice in this study were given this mutation, and all of them developed melanoma when exposed to UV light.

Sunscreen factor 50 delayed the onset and reduced the number of tumours, but did not prevent melanoma.

The study also found that in the mice with the BRAF mutation, UV light damaged another part of the DNA that stops cells dividing too rapidly – tumour suppressor genes called TP53. Sunscreen did not prevent this damage, which means that the cells could grow unchecked.

Mutations in the BRAF gene found in melanomas are not the inherited type, and in humans may be caused by UV exposure and other environmental factors.

It should not be interpreted from this study that sunscreen is useless, but you cannot rely on it solely, especially if you have risk factors for melanoma, such as pale skin and having lots of moles.

Sunscreen should be used in combination with other preventative methods, such as wearing appropriate clothing when the sun is at its hottest.

 

Where did the story come from?

The study was carried out by researchers from the University of Manchester, the Institute of Cancer Research and the Royal Surrey County Hospital. It was funded by Cancer Research UK, the Wenner-Gren Foundations and a FEBS Long-Term Fellowship.

The study was published in the peer-reviewed medical journal Nature.

It was accurately covered in the UK media, with many news sources including useful quotes from independent experts about the research's implications. 

 

What kind of research was this?

This was a laboratory study that used mice to look at how effective sunscreen is at reducing the risk of developing melanoma, following exposure to UV light.

Melanoma is the most malignant form of skin cancer. It is the fifth most common cancer in the UK, with 13,348 new cases occurring each year, according to figures from 2011.

Melanoma occurs when melanocytes grow uncontrollably. These are the cells that produce the protective pigment melanin, which gives skin its colour. People with darker skin have more active melanocytes, which transfer more melanin to other cells to protect them from UV light.

A mutation in the BRAF gene that regulates growth and division of cells has been found in melanoma. It is known as an “oncogene”, as it can cause normal cells to become cancerous if it has a mutation. Several different BRAF gene mutations have been found in melanoma and some cancers of the colon, rectal, ovary and thyroid.

It is not known how UV light causes melanoma, but an abnormal BRAF gene has commonly been found at an early stage in the development of melanoma. The researchers wanted to study the process, so used mice that had this particular BRAF gene mutation (called BRAF [V600E]).

Another gene, tumour protein 53 (TP53), makes a protein called tumour suppressor 53 (Trp53) that stops cells dividing too rapidly or uncontrollably. If there is a mutation in this gene, there is no safety check and the cells can grow and multiply unchecked, causing a tumour. Trp53 has been implicated in non-melanoma skin cancer, but was not thought to be involved in melanoma.

 

What did the research involve?

Mice with the BRAF gene mutation in their melanocytes were used in a variety of experiments and compared to mice without the BRAF mutation.

The backs of the mice were shaved and one half was protected with a cloth.

Newborn mice were given a single exposure to UV light at a dose that would mimic mild sunburn in humans. Those also given the BRAF mutation were compared to those without.

Adolescent mice were given the BRAF mutation and then either:

  • not exposed to UV light
  • given weekly exposure to UV light for up to six months
  • repeated exposure to UV light 30 minutes after sunscreen factor 50 had been applied

 

What were the basic results?

The newborn mice given the BRAF mutation developed melanoma. This was found to be due to the inflammatory response of the skin.

In the adolescent mice given the BRAF mutation:

  • melanoma occurred in 70% of the mice with no UV exposure after about 12.6 months. They had, on average, 0.9 tumours (this somewhat unusual average is due to the fact that some mice had no tumours – much like the famous example of 2.4 children)
  • all mice developed melanoma after repeated UV exposure within 7 months. They had, on average, 3.5 tumours each; 98% of them were on the skin exposed to the UV light
  • all mice given sunscreen developed melanoma within 15 months. They had, on average, 1.5 tumours each, and were more common on the sunscreen-protected skin than the cloth-protected skin

Mice without the BRAF gene mutation did not develop melanoma after exposure to UV rays.

UV light caused damage to the DNA. This was evidenced by finding mutations in the Trp53 tumour suppressor protein in 40% of cases. These mutant Trp53 proteins increased the BRAF-driven growth of the melanoma.

 

How did the researchers interpret the results?

The researchers conclude that this study reveals “two UVR melanoma pathways: one driven by inflammation in neonates and one driven by UVR-induced mutations in adults”. They also found that “sunscreen (UVA superior, UVB sun protective factor [SPF] 50) delayed the onset of UVR-driven melanoma, but only provided partial protection”. They “advocate combining it with other sun avoidance strategies, particularly in at-risk individuals with BRAF-mutant naevi [moles]”.

 

Conclusion

This study found that in mice given the BRAF mutation, sunscreen did not prevent them from developing melanoma, although it did delay it and reduce the number of tumours. The mechanism for this appears to include damage to a tumour suppressor gene, TP53, which has previously been implicated in other skin cancers. Sunscreen did not prevent mutations occurring in this gene, but did reduce the number of mutations.

The study's authors accepte that sunscreen protects against squamous cell carcinoma – a type of skin cancer – but that there was uncertainty around its ability to protect against malignant melanoma – a second type of skin cancer. This study indicated that sunscreen did reduce the risk of developing melanoma in the mice, but that protection was not 100%. These preliminary findings in mice will need to be confirmed in humans for the results to be more credible and reliable.

These results were applicable only to those with an existing mutation in the BRAF gene. Mutations in the BRAF gene can be inherited, but these are not thought to be linked to skin cancers. Acquired mutations in the BRAF gene do increase the risk of melanoma, and can be present in moles. These people have a heightened risk of skin cancer. The complication that arises from this is that UV light might cause this mutation, setting off a cycle of cell and DNA damage, leading to cancer. This means that overexposure to the sun still increases your risk of skin cancer risk factors, whether you have the mutation or not.

People with known risk factors for melanoma should use high-factor sunscreen in combination with other preventative methods, such as wearing appropriate clothing and staying in the shade when the sun is at its hottest (between 11am and 3pm). If you are desperate for a tan, fake is the best way to go.

Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

High-factor sunscreen cannot give complete protection against skin cancer. The Guardian, June 12 2014

Skin cancer: Sunscreen 'not complete protection'. BBC News, June 11 2014

Wearing sunscreen may NOT prevent skin cancer, study claims. Mail Online, June 12 2014

Sunscreen does not protect against deadliest skin cancer. The Daily Telegraph, June 12 2014

Links To Science

Viros A, Sanchez-Laorden B, Pedersen M, et al. Ultraviolet radiation accelerates BRAF-driven melanomagenesis by targeting TP53. Nature. Published online June 11 2014

Categories: Medical News

Making mosquitoes male may manage malaria

Medical News - Wed, 06/11/2014 - 18:19

"Mosquitoes modified to only give birth to males in bid to wipe out malaria," The Daily Telegraph reports after new research has found an innovative way of tackling the global problem of malaria.

The technique used in this latest research is both brutal and elegant. Female mosquitoes, which spread malaria to humans through their bite, were genetically modified so that their offspring were overwhelmingly (95%) male. This male-only trait was inherited and repeated with future generations, and has the potential to wipe the species out.

It is not yet known if the genetically modified mosquitoes are able to compete with wild mosquitoes in their natural environment, as the studies have so far only been conducted in cages in a laboratory.

If the mosquitoes can have an effect in the wild, in the short-term this could reduce the spread of malaria by cutting the number of female mosquitoes. In the long-term, the species could potentially be completely eliminated.

Future studies would have to ensure that wiping out the type of mosquito that carries malaria does not upset the ecosystem and cause more problems.

A famous example of this type of ecological upset is the introduction of cane toads in Australia to manage the beetle population. The toads proved highly adaptive to the environment and are now a major pest.

 

Where did the story come from?

The study was carried out by researchers from Imperial College London, the University of Perugia in Italy, and the Fred Hutchinson Cancer Research Center in the US.

It was funded by the US National Institutes for Health and the European Research Council.

The study was published in the peer-reviewed medical journal, Nature Communications. It is open access, so it is free to read online.

The UK media's coverage was good, with The Guardian providing expert comments on the study balanced by a quote from Dr Helen Williams, director of GeneWatch UK, regarding the potential risks of interrupting the ecosystem.

 

What kind of research was this?

This was a laboratory study of mosquitoes that aimed to find a way of reducing their numbers, as female mosquitoes – which bite humans – spread malaria.

The number of female mosquitoes in the mosquito population and their speed of reproduction are both believed to be ways of controlling their population size. If there was a way to increase the proportion of male offspring, this could therefore reduce the population size.

Previous attempts in caged experiments using naturally occurring mutations – which gave a higher number of male offspring in two types of mosquito called Aedes and Culex – were unsuccessful because the females had a natural resistance to them.

The researchers aimed to genetically modify mosquitoes using a synthetic enzyme, based on the naturally occurring mutations, to damage the X chromosome in males. This would mean that they are potentially only able to pass on the Y chromosome during reproduction, thereby only producing male offspring.

 

What did the research involve?

The researchers investigated the effect of different enzymes on damaging the X chromosome of male mosquitoes in the laboratory and then performed various experiments using live mosquitoes.

They created an enzyme that targets and damages the X chromosome in the male mosquito species Anopheles gambiae, which carries malaria.

The researchers ensured that the process only damaged the X chromosome in the male mosquito and did not affect the Y chromosome so that the offspring were not sterile.

If they were sterile, they would not be able to reproduce and the effects of the genetically modified mosquitoes would be limited to one generation.

This would then require an unimaginable number of mosquitoes to be injected for there to be any impact on numbers.

The researchers performed various experiments to see if the genetic mutation would be passed on to future generations.

They tested the level of damage to the X chromosome caused by various enzymes and at different temperatures until they found the optimal genetic modification that was able to produce mostly males without affecting the fertility rate.

 

What were the basic results?

The offspring of genetically modified male mosquitoes were more than 95% male. The enzyme that damages the X chromosome was inherited by these males, causing them to have male offspring.

In five independent cage experiments, putting in three times the number of genetically modified males to normal males caused the suppression of the wild-type mosquito. All mosquitoes were eventually eliminated in four of the cages within six generations.

In the small fraction of female offspring produced by the genetically modified males, their offspring were mostly female when they were fertilised by wild male mosquitoes.

The male offspring had a 50% chance of having the genetic modification. When they were crossed with wild female mosquitoes, however, they were still more likely to have males.

 

How did the researchers interpret the results?

The researchers concluded that, "Distorter male mosquitoes can efficiently suppress caged wild-type mosquito populations, providing the foundation for a new class of genetic vector control strategies."

However, they acknowledge that, "The robustness of these traits under variable natural conditions remains to be studied."

 

Conclusion

This study found that genetically modifying the X chromosome in male mosquitoes can cause more than 95% of their offspring to be male in caged experiments. This genetic modification is inherited by these offspring, who then have similar high numbers of male offspring.

While these results are promising, it is not clear whether the small fraction of female offspring would be enough to eventually reverse the process and create mosquitoes resistant to the effects of the enzyme.

These studies were just performed on the species Anopheles gambiae, which carries malaria. It is not yet known what effect reducing or eliminating the species would have on the population size of other mosquitoes or the ecological system.

This would need to be considered carefully before any genetically modified species was released into the environment. Our ecosystem is incredibly complex, so tinkering with it could lead to a range of unexpected and unwanted consequences.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Mosquitoes modified to only give birth to males in bid to wipe out malaria. The Daily Telegraph, June 10 2014

GM mosquito designed to kill off females may limit spread of malaria. The Times, June 11 2014

GM mosquitoes a 'quantum leap' towards tackling malaria. The Guardian, June 10 2014

GM lab mosquitoes may aid malaria fight. BBC News, June 10 2014

Could malaria be wiped out by GM mosquitoes? Scientists find a way to kill off disease-carrying female of the species. Daily Mail, June 10 2014

New GM Mosquito 'Could Help Defeat Malaria'. Sky News, June 10 2014

Links To Science

Galizi R, Doyle LA, Menichelli M, et al. A synthetic sex ratio distortion system for the control of the human malaria mosquito. Nature Communications. Published online June 10 2014

Categories: Medical News

Red meat consumption linked to breast cancer

Medical News - Wed, 06/11/2014 - 14:26

“Eating a lot of red meat in early adult life may slightly increase the risk of breast cancer,” BBC News reports.

The news is based on a large US study that looked at the protein dietary intake of almost 90,000 female nurses and their risk of breast cancer over a 20-year period.

Previous studies have focused on the dietary intake of those in their "midlife" and older populations. In this particular study, however, researchers were interested in finding the potential link between diet and breast cancer risk in early adulthood.

The main finding was that a higher intake of red meat (which included both processed and unprocessed meat) was associated with a 22% increased risk of breast cancer.

The results suggest that women who chose healthier sources of protein – such as chicken, nuts and lentils – had a decreased risk of breast cancer.

The study is certainly not without its limitations, particularly because it relied on participants’ recall of dietary intake.

However, there is evidence that reducing your consumption of red meat to 70g a week or less could also reduce your risk of bowel cancer.

 

Where did the story come from?

The study was carried out by researchers from Harvard School of Public Health in the US, Shahid Beheshti University of Medical Sciences in Tehran, Iran, and other US institutions.

It was funded by the National Institutes of Health and was published in the peer-reviewed journal BMJ. The article has been published on an open-access basis, meaning it is freely available to read online.

The researchers previously carried out an early analysis of this study with a 12-year follow up period and published their findings. Their current publication has a longer follow-up period, of 20 years. 

The story was covered extensively in the UK media, and most of the coverage accurately reflects the study’s findings.

However, the Mail Online reported that “three bacon rashers a day raises breast cancer risk for young women”, but it is unclear where the figure of three rashers came from.

The study only reports data for total red meat consumption, including both processed and unprocessed, with precise quantities (in either grams or number of items) not provided.

 

What kind of research was this?

This was a prospective cohort study investigating the link between dietary protein in early adulthood and the risk of breast cancer.

A cohort study looks at how particular exposures affect groups of people over time. This type of research is normally used to look at the effect of suspected risk factors that cannot be controlled experimentally – for example, the effect dietary protein plays on the risk of breast cancer. Results from prospective studies are usually considered as more robust then retrospective studies, which either use data that was collected in the past for another purpose, or ask participants to remember what happened to them in the past.

 

What did the research involve?

The study included 88,803 female nurses aged between 24 and 43, all from the US. These women had all participated in a wider study (Nurses Health Study II) and had completed a questionnaire about usual dietary intake in the past year, in 1991.

The researchers considered the findings from the 1991 questionnaire to represent dietary intake in early adulthood. 

The nurses then completed the same, or a similar, questionnaire in 1995, 1999, 2003 and 2007. In the questionnaires, responses were given for commonly used portion sizes, with nine categories of intake frequency that ranged from “never or less than once per month” to “six or more per day”.

For analysis purposes, women were categorised into one of five categories, according to food group or nutrient intake.

The researchers were interested in investigating the potential link between total intake of unprocessed red meat (e.g. beef, pork, lamb) and processed red meat (e.g. hot dogs, bacon, salami) before menopause and the subsequent risk of breast cancer up to 2011 (in the 20-year follow-up period).

In addition to this, they looked at links between breast cancer and other protein-rich foods, including:

  • poultry (e.g. chicken, turkey)
  • fish
  • eggs
  • legumes (e.g. tofu, lentils, soybeans)
  • nuts

The main outcome the researchers were interested in was the number of breast cancer cases identified through self-reporting and confirmed with pathology. New cases of breast cancer were identified every two years, through questionnaires.

The researchers used statistical techniques to analyse their results and adjusted the results for multiple factors, including family history of breast cancer, energy intake and smoking.

They analysed their results for all women, as well as by menopausal status.

Women were considered premenopausal if they still had menstrual periods or had a hysterectomy with at least one ovary remaining, and were younger than 46 (for smokers) or 48 years (for non-smokers).

Women were considered postmenopausal if they reported no longer having menstrual periods or had undergone surgery to remove both their ovaries.

They also estimated the effect of substituting one serving per day of poultry, fish, legumes, eggs or nuts for one serving of red meat.

 

What were the basic results?

The average age of women in 1991 was 36.4 years. Over the 20-year follow-up period, there were 2,830 cases of breast cancer recorded. The main findings of the study were that:

  • higher intake of total red meat was associated with an increased risk of overall breast cancer (relative risk [RR] 1.22, 95% confidence interval [CI] 1.06 to 1.40 for highest fifth of red meat consumption, compared to the lowest fifth of consumption)
  • higher intakes of poultry, fish, eggs, legumes and nuts were not associated with overall risk of breast cancer
  • higher intake of poultry was associated with a lower risk of breast cancer among postmenopausal women (RR 0.73, 95% CI 0.58 to 0.91) for highest fifth of consumption compared to lowest fifth), but not in premenopausal women (RR 0.93, 95% CI 0.78 to 1.11 for highest fifth compared to lowest fifth of consumption)

Findings were not presented for processed vs. unprocessed meats and risk of breast cancer.

When estimating the effects of exchanging different protein sources:

  • substituting one serving of legumes (such as nuts, peas and lentils) a day for one serving of red meat a day was associated with a 15% lower risk of breast cancer among all women (RR 0.85, 95% CI 0.73 to 0.98) and a 19% lower risk among premenopausal women (RR 0.81, 95% CI 0.66 to 0.99)
  • substituting one serving of poultry a day for one serving of red meat a day was associated with a 17% lower risk of overall breast cancer (RR 0.83, 95% CI 0.72 to 0.96) and a 24% lower risk of postmenopausal breast cancer (RR 0.76, 95% CI 0.59 to 0.99)
  • substituting one serving a day of combined legumes, nuts, poultry and fish for one serving a day of red meat was associated with a 14% lower risk of overall breast cancer (RR 0.86, 95% CI 0.78 to 0.94) and premenopausal women (RR 0.86, 95% CI 0.76 to 0.98)

 

How did the researchers interpret the results?

The researchers concluded that a higher intake of red meat in early adulthood may be a risk factor for breast cancer, and that replacing red meat with a combination of legumes, poultry, nuts and fish may reduce this risk.

 

Conclusion

Overall, this cohort study found that a higher intake of red meat was associated with higher risk of breast cancer among a large group of US female nurses. The studies strengths include the large population size, the study’s prospective nature and the fact there was a relatively long follow-up period (20 years).

The researchers note limitations to their study, which should be considered when interpreting the findings. These include the fact that:

  • the participants were predominantly white, educated US females, so caution should be taken when generalising the findings to other races or ethnic groups
  • dietary intake was assessed using a food frequency questionnaire, which relied on participants recalling their dietary intake over the previous year. It is likely that participants did not accurately report their dietary intake, which introduces some measurement bias
  • the researchers adjusted their results for multiple confounders (e.g. family history of breast cancer and smoking); however, it is possible that other factors, which the researchers did not take into account, could have affected results
  • the findings related to substituting foods are estimates only and may not reflect actual effects of protein substitution

It is important to note that this is only one study and needs to be interpreted alongside the wider body of current evidence related to dietary factors and cancer risk.

It is not yet clear whether this study, alongside other potential future evidence, will lead to a different set of conclusions about dietary links with breast cancer.

However, it should not be concluded from this particular study alone that red meat and processed meat increase the risk of breast cancer.

To try and reduce your risk of cancer overall, you should follow a healthy, balanced diet high in fruit and vegetables, and low in saturated fats and sugars, as well as limiting your alcohol intake and exercising in line with recommendations.     

Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

Red meat 'linked to breast cancer'. BBC News, June 11 2014

Replace red meat with chicken to cut breast cancer risk. The Daily Telegraph, June  11 2014

Three bacon rashers a day 'raises breast cancer risk for young women': Frequently eating red meat can raise chance of developing disease by more than 20%. Mail Online, June 10 2014

Women who eat lots or red meat 'at increased risk' of breast cancer. Daily Mirror, June 10 2014

Breast cancer link to higher red meat consumption greeted with scepticism. The Guardian, June 10 2014

Links To Science

Farvid MS, Cho E, Chen WY, et al. Dietary protein sources in early adulthood and breast cancer incidence: prospective cohort study. BMJ. Published online June 10 2014

Categories: Medical News

Tomato extract's heart effects exaggerated

Medical News - Tue, 06/10/2014 - 16:17

“Ketchup with everything: tomato sauce helps fight heart disease,” is the misleading headline in The Daily Telegraph.

The headline follows a small study conducted into lycopene tablets, which involved 36 people with cardiovascular disease and 36 healthy volunteers. Lycopene is the pigment that gives tomatoes (and some other fruit and veg) their distinctive colour. It has been the subject of numerous research projects in recent years, as it is thought to have antioxidant properties that may help protect against diseases that affect the heart and blood vessels (cardiovascular diseases).

This latest study found that people with cardiovascular disease who took statins saw their blood vessels dilate (widen) to a greater extent after they were treated with a chemical called acetylcholine if they had been taking lycopene every day for two months, rather than a placebo.

The lycopene tablet had no significant effect on any of the other outcomes the researchers looked at, and no effect on healthy volunteers (apart from increasing lycopene levels in the blood).

While improving the dilation of blood vessels may hypothetically reduce the risk of cardiovascular disease, this remains unproven in a real life setting.

Larger, longer-term studies are required to determine whether taking lycopene actually cuts the risk of heart attack and stroke.

 

Where did the story come from?

The study was carried out by researchers from the University of Cambridge and Cambridge University Hospitals NHS Foundation trust in the UK, and the University of Tartu, in Estonia. Funding was provided by Cambridge University Hospitals NHS Foundation Trust. The individual researchers were funded by the Wellcome Trust, the British Heart Foundation, the Estonian Science Foundation, the European Union Social Fund and the National Institute of Health Research Cambridge Comprehensive Biomedical Research Centre.

The study was published in the peer-reviewedopen-access journal PLOS One and can be read for free online.

Misleading headlines aside, the media have reported the story accurately and highlighted that larger studies are required to determine whether the effects shown here will have real health benefits.

 

What kind of research was this?

This was a randomised controlled trial (RCT) that aimed to investigate the effects of lycopene, the red pigment found in tomatoes (and certain other fruits and vegetables), on the blood vessels of patients with cardiovascular disease who were taking statins, as well as on healthy volunteers.

Previous research has found a link between reduced cardiovascular disease and the “Mediterranean diet”; the researchers wanted to see if this could be, at least partially, due to lycopene.

RCTs are the best way of demonstrating a cause-and-effect relationship. However, this was a small-scale trial, and the findings need to be replicated in a larger group of people.

 

What did the research involve?

The researchers randomised 36 patients with cardiovascular disease who were taking statins to either 7mg lycopene or a placebo daily for a two-month period.

The researchers then looked at the responses of blood vessels in the arm to acetylcholine – a chemical that causes them to dilate.

They also looked at the responses of blood vessels to other chemicals that cause them to dilate or contract, arterial stiffness, blood pressure, levels of different markers in the blood, as well as safety and tolerability.

The researchers then repeated these tests with 36 healthy volunteers.

 

What were the basic results?

Among the patients with cardiovascular disease who were randomised to take lycopene, dilation after acetylcholine improved by 53% and was significantly different to dilation in patients with cardiovascular disease who were randomised to take placebo.

There were no differences in the response of blood vessels to other chemicals, in arterial stiffness, blood pressure or the levels of different markers in the blood, apart from lypocene levels.

Lycopene had no effect in healthy volunteers on any of the outcomes investigated, apart from levels of lycopene in the blood. 

 

How did the researchers interpret the results?

The researchers concluded that “despite optimal secondary prevention medication, endothelial function [the function of the cells that line blood vessels] is impaired in patients with cardiovascular disease, and this is improved by oral supplementation with 7 mg lycopene, without any concomitant changes in traditional risk factors such as [blood pressure] or lipid profiles, or measures of inflammation. In contrast, we were unable to demonstrate any changes in endothelial function or other parameters after lycopene treatment in [healthy volunteers].”

 

Conclusion

This study found that the blood vessels in people with cardiovascular disease who were taking statins dilated more after they were treated with a chemical called acetylcholine if they had been taking lycopene every day for two months, compared to those taking placebo pills.

The lycopene tablet had no significant effect on any of the other outcomes the researchers looked at, and no effect in healthy volunteers, although it did increase lycopene levels in the blood. 

Although impaired endothelial function is a known predictor of future heart disease, this is, at best, a surrogate outcome. It is no substitute for following up people over time to see if improvement in endothelial function actually does translate into reduced deaths from heart attacks and stroke. 

Due to this limitation, much larger RCTs, with a follow-up period measured in years rather than months, are required to determine whether taking lycopene actually cuts the risk of cardiovascular disease.

Many unanswered questions remain about why eating a Mediterranean diet seems to reduce the risk of heart attack and stroke, but the benefits of the diet seem to be real.

Analysis by Bazian. Edited by NHS Choices
Follow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

Ketchup with everything: tomato sauce helps fight heart disease. The Daily Telegraph, June 10 2014

'Tomato pill' hope for stopping heart disease. BBC News, June 9 2014

Tomato extract relieves damaged arteries, finds Cambridge study. The Guardian, June 9 2014

£1-a-day tomato pill that helps your heart: Treatment can increase blood vessel flow by 50% in patients with cardiac problems. Mail Online, June 10 2014

Tomato pill could prevent heart attacks say experts. Daily Express, June 10 2014

Links To Science

Gajendragadkar PR, Hubsch A, Mäki-Petäjä KM, et al. Effects of Oral Lycopene Supplementation on Vascular Function in Patients with Cardiovascular Disease and Healthy Volunteers: A Randomised Controlled Trial. PLOS One. Published online June 9 2014

Categories: Medical News

One in three adults in England 'has prediabetes'

Medical News - Tue, 06/10/2014 - 14:00

"One in three adults in England 'on cusp' of diabetes," BBC News and others report. The media reports are based on a study that estimated that 35.3% of adults in the UK now have prediabetes (also known as borderline diabetes).

Prediabetes is where blood sugar levels are abnormally high, but lower than the threshold for diagnosing diabetes. It is estimated that around 5-10% of people with prediabetes will go on to progress to "full-blown" type 2 diabetes in any given years.

Researchers analysed information from the Health Survey for England (HSE). This is a survey that combines questionnaire-based answers with physical measurements and the analysis of blood samples from a representative sample of the English population.

This study found that there has been a significant increase between 2003 and 2011 in the proportion of people aged 16 or older with prediabetes, from 11.6% in 2003 to 35.3% in 2013.

Known risk factors, confirmed in this study, include age (40 and above), body mass index (25 and above), being of south Asian ethnicity, and having high blood pressure.

If you think you may be at high risk of prediabetes, you can ask your GP for a blood test. It is often possible to prevent the condition progressing into diabetes proper through lifestyle changes, such as improving your diet and exercising more.

 

Where did the story come from?

The study was carried out by researchers from the University of Florida and the University of Leicester, and was somewhat surprisingly funded by the US Department of Defense.

It was published in the peer-reviewed BMJ Open, an open access medical journal, so the study is free to read online.

This study was accurately reported in the UK media, with many articles also helpfully outlining the complications of diabetes, its impact on public health, and some relevant contextual information.

For example, this included information about the NHS Health Check programme, which invites people between the ages of 40 and 74 to have a check to assess their risk of heart disease, stroke, kidney disease and diabetes, and to give support and advice to help people reduce or manage their risk.

But as the NHS Health Check programme is in its infancy, it is hard to estimate what the likely take-up will be in the future and what impact it will have on public health.

 

What kind of research was this?

This was a cross-sectional study that aimed to report trends in the prevalence of prediabetes among people aged 16 or older in England.

Cross-sectional studies are the ideal way of determining how many people have a condition.

 

What did the research involve?

The research used information collected by the Health Survey for England (HSE) in the years 2003, 2006, 2009 and 2011.

The HSE is an annual population-based survey that combines questionnaire-based answers with physical measurements and the analysis of blood samples from a random sample of participants.

People were classified as having prediabetes if they had glycated haemoglobin (an indicator of blood sugar levels) between 5.7% and 6.4% and had not previously been diagnosed with diabetes.

Glycated haemoglobin is formed when haemoglobin is exposed to glucose in the blood. As the amount of glucose in the blood increases, the fraction of haemoglobin that is glycated increases.

Diabetes is diagnosed when the level is 6.5% or above. However, there is no internationally agreed lower level for prediabetes.

The American Diabetes Association uses 5.7% as the lower cut-off level, but a UK expert group for the National Institute for Health and Care Excellence (NICE) recommend 6.0-6.4%.

 

What were the basic results?

The prevalence of prediabetes increased over the study period. It was:

  • 11.6% in 2003
  • 20.4% in 2006
  • 32.6% in 2009
  • 35.3% in 2011

Age, being overweight, obesity, blood pressure level and cholesterol level exhibited significant relationships with prediabetes in all years that these were measured.

People with greater socioeconomic deprivation were more likely to have prediabetes in 2003 and 2006, but the relationship was no longer significant in 2009 and 2011.

The researchers found that predictors of prediabetes in 2003 and 2011 included:

  • being 40 years or older
  • being of south Asian ethnicity
  • having a high body mass index (BMI) of 25 or over
  • having been diagnosed with high blood pressure
  • being socioeconomically deprived (being in the second most deprived quintile)

 

How did the researchers interpret the results?

The researchers concluded that, "There has been a marked increase in the proportion of adults in England with prediabetes. The socioeconomically deprived are at substantial risk.

"In the absence of concerted and effective efforts to reduce risk, the number of people with diabetes is likely to increase steeply in coming years."

 

Conclusion

This study indicates that there had been an increase between 2003 and 2011 in the proportion of people aged 16 or older with prediabetes, with more than a third of adults in 2011 having prediabetes.

The study is useful because it is based on information from the Health Survey for England (HSE), which sampled a representative sample of the English population.

However, the researchers defined prediabetes using cut-offs used by the American Diabetes Association (5.7-6.4%), but in the UK NICE recommends higher cut-offs to identify people at high risk of diabetes (6.0-6.4%).

There are several ways you can reduce your risk of developing type 2 diabetes:

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

One in three adults in England 'on cusp' of diabetes. BBC News, June 10 2014

One in three adults have borderline diabetes, study finds. The Daily Telegraph, June 10 2014

Study reveals sharp rise in English people at risk of getting type 2 diabetes. The Guardian, June 9 2014

One in three adults 'on cusp of diabetes' in England. The Independent, June 10 2014

A third of adults have 'borderline' diabetes - but most don't know: Rising tide of obesity means number who have 'prediabetes' has trebled since 2006. Daily Mail, June 10 2014

Obesity levels mean number of adults with diabetes has tripled in just eight years. Daily Mirror, June 9 2014

One In Three Adults Have Borderline Diabetes. Sky News, June 10 2014

Over a third of adults have 'borderline diabetes'. ITV News, June 10 2014

Links To Science

Mainous III AG, Tanner RJ, Baker R, et al. Prevalence of prediabetes in England from 2003 to 2011: population-based, cross-sectional study. BMJ Open. Published online June 9 2014

Categories: Medical News

Is obesity jab 'two years away'?

Medical News - Mon, 06/09/2014 - 14:26

“New obesity jab could be available within two years,” the Mail Online reports. The headline comes following news that scientists have identified a protein that may help stimulate the production of brown fat.

Brown fat helps keep mammals warm. In humans, it is mostly found in newborn babies, who are particularly vulnerable to cold. As we age, we do not need brown fat as much, and in adulthood we have mostly white fat. Excess white fat (obesity) can damage your health, whereas brown fat has been linked to protection against obesity and type II diabetes; as such, it has attracted increasing interest and research.

Brown fat also helps to burn calories when the body is exercising (or, less pleasantly, when you are cold enough to shiver). Unlike white fat, it acts like muscle, keeping the body firm and toned.

The study, which involved mice rather than people, found that the new protein helped stimulate the production of brown fat. 

The optimism surrounding these findings is based on the hope that researchers could potentially harness the effects of this molecule to develop an obesity treatment in the future.

However, claims that an “obesity jab could be available within two years” seem overly optimistic.

Studies on people are needed before any claims of this kind can be made.

 

Where did the story come from?

The study was carried out by researchers from Harvard Medical School and the Dana-Farber Cancer Institute, in the U.S., and was funded by grants from the US National Institutes of Health and JPB Foundation.

The study was published in the peer-reviewed science journal Cell.

The Mail Online’s headline that “a new obesity job could be available within two years” is not supported by the publication, although the authors did state that the “therapeutic potential in metabolic diseases is obvious”. 

There was a related study, performed by the same research team, in which the effects of the hormone irisin were studied, also in mice. Evidence suggests that irisin can also help stimulate production, by turning white fat into brown fat.

Somewhat confusingly, the Mail Online and the Daily Express seem to have reported on the findings of both studies as if they were a single piece of research.

 

What kind of research was this?

This was a laboratory study that used mice to identify and investigate the function of hormones released in muscles in response to exercise and cold.

Obesity levels in middle- and high-income countries is high and continuing to rise, with associated diseases including type 2 diabetes, cardiovascular disease and cancer.

As a result, the authors state there is increasing interest in brown fat – which uses energy to create heat and stops mammals becoming overly cold. In humans, brown fat is mostly found in newborn babies, who are particularly vulnerable to cold (as they have a large surface area to body volume ratio and are unable to shiver). As we age, we do not need as much brown fat to keep us warm, and have mostly white fat. However, brown fat has also been linked to protection against obesity and type II diabetes. Some hope that finding a way to make the body produce more brown fat, or convert white fat into brown fat, may help prevent obesity.

Exercising is a simple way to increase energy expenditure, and helps prevent obesity and associated metabolic disorders. It also increases the circulating levels of certain hormones released from muscle, which are known to mediate some of the beneficial effects of exercise.

The researchers wanted to see if there was the potential to harness some of these hormones to artificially mimic the beneficial effects of exercise, and investigated the role of brown fat in this process.

 

What did the research involve?

The research involved numerous genetic and protein studies involving mice. They were looking for molecules that were released during exercise and in response to cold, which would give them clues as to how exercise and brown fat activity were generating health benefits. By screening numerous molecules, they sought to identify those that were having the most important effects. 

What were the basic results?
  • The experiments identified a molecule called meteorin-like (Metrnl), which was present in muscle and fat.
  • Circulating levels of Metrnl rose after mice exercised and when they were exposed to the cold. 
  • Metrnl was found to stimulate energy expenditure and converted regular fat into heat-producing brown fat. Metrnl also improved glucose tolerance – a sign of metabolic health – in mice fed a high-fat diet. It was doing this by interacting with many aspects of the body’s immune system and its temperature regulation systems.
  • Blocking Metrnl action stopped these beneficial effects – confirmation that it was heavily involved in this process.  
  • Metrnl levels increased as a result of repeated bouts of prolonged exercise, but not during short-term muscle activity.

 

How did the researchers interpret the results?

The researchers concluded that Metrnl’s “therapeutic potential in metabolic diseases is obvious. The recombinant Metrnl protein used here hints at that potential, but other proteins with better pharmacological properties will be required”.

 

Conclusion

This study identified a molecule that is induced by exercise and exposure to cold. It has been implicated in stimulating brown fat development and improving glucose tolerance – both of which have been linked to a lower risk of obesity and type II diabetes, giving hope that harnessing the effects of this molecule could create obesity treatments.

However, this optimism appears premature, as the research was conducted solely in mice. It will need to be reproduced and validated in humans to see if it is safe and effective at stimulating weight loss or other benefits. These remain unproven at this stage.

Other promised potential “anti-obesity jabs” include leptin and irisin, neither of which have delivered convincing results in human trials. This serves to highlight that when a new compound shows promise in mice, these don’t necessarily translate into effective medicines for humans.

On this basis, the Mail’s headline that a “new obesity jab could be available within two years” appears unjustified.

Rather than holding out hope of some magic medical bullet to beat or treat obesity, it’s best to try and lose weight through healthy eating and exercise. Our free 12-week NHS Weight Loss plan can help you achieve sustainable weight loss.

Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

New obesity jab could be available within two years after scientists discover hormone that helps the body burn fat. Mail Online, June 6 2014

New drug boosting immune system could beat obesity and diabetes. Daily Express, June 6 2014

Links To Science

Rao RR, Long JZ, White JP, et al. Meteorin-like Is a Hormone that Regulates Immune-Adipose Interactions to Increase Beige Fat Thermogenesis. Cell. Published online June 5 2014

Categories: Medical News

Cannabis can damage lives, researchers argue

Medical News - Mon, 06/09/2014 - 14:00

“Smoking marijuana as a teenager lowers IQ for life, scientists warn,” the Mail Online reports. The headline is prompted by a critical review looking at the evidence about the potential harms associated with cannabis use.

This latest review was written by researchers from the US National Institute on Drug Abuse and provides an overview of the potential harms associated with cannabis use, ranging from increased risk of car accidents to an adverse effect on “life achievement”.

The Mail’s coverage of the story was an accurate representation of the research, although it took the review findings at face value and did not mention any of its limitations. The most important of which is that it does not appear to be a systematic review, where all available evidence on a particular topic is assessed.

It is unclear whether this study was prone to “cherry picking” – where evidence that supports the researchers’ arguments is included while evidence that opposes it is ignored. This has the potential to bias the findings and conclusions.

The timing of the study is also interesting. After the quasi-legalisation of cannabis in the states of Colorado and Washington there have been increasing calls to roll-out similar laws across America.

Many of the review's conclusions were tentative or indicated more research was needed. Based on this review alone, research into the effects of cannabis use in humans has not yet yielded any firm conclusions and often paints an unclear or inconsistent picture.

 

What is the basis for these current news reports about cannabis?

The authors state cannabis (marijuana) is the most commonly used illicit drug in the US with around 12% of people over the age of 12 reporting use in the past year, with particularly high rates among young people.

The regular use of cannabis in adolescence was of particular concern to the review group because of a higher chance of potential harm in younger groups.

The review highlighted a popular belief of cannabis as a harmless vice. Given the loosening of laws and regulation on recreational use in in some US states (Colorado and Washington), some may see this as giving legitimacy to this idea. And in response to the increase in the legalisation of cannabis for medical and recreational use in the US, patients may be more likely to ask their doctors about its potential benefits and risks to health.

The authors indicated many scientific studies report harmful effects associated with cannabis but others do not, which has led to heated debate about whether cannabis is harmful.

The review aimed to assess the current state of the science on the adverse health effects of recreational cannabis use, focusing on those areas for which the evidence is strongest.

 

What did the report find?

The review was broad, covering addiction, neurodevelopment, mental illness, risk of cancer and life chances.

Risk of addiction

The authors indicated that, “despite some contentious discussions regarding the addictiveness of marijuana, the evidence clearly indicates that long-term marijuana use can lead to addiction”. Around 9% of those who experiment with cannabis become addicted, and this figure rises to 50% of those who smoke it every day, the review said.

Effect on brain development and IQ

The negative effects of cannabis use on the brain were said to be particularly prominent if use starts in adolescence or young adulthood. The review flagged up one study that found an association between frequent use of cannabis from adolescence into adulthood with significant declines in IQ.

Role as a gateway drug

There is a theory that using cannabis in early adulthood could encourage the use of other addictive drugs such as nicotine or alcohol. The review found animal studies that were consistent with this theory. However, they also acknowledged they didn’t know whether people with more addictive tendencies are more likely to try cannabis, alcohol and nicotine, or whether cannabis use itself directly increased the chances of them trying these things.

Mental illness

Regular cannabis use was reported to be associated with an increased risk of anxiety and depression, but causality has not been established.

It has also been linked to psychosis (including those associated with schizophrenia), especially among people with a pre-existing genetic vulnerability, and worsens illness in people with schizophrenia.

The authors say it is difficult to establish causality in these types of studies, because factors other than cannabis use may be directly associated with the risk of mental illness. Other factors could also predispose a person to both cannabis use and mental illness. This makes it difficult to confidently attribute the increased risk of mental illness to cannabis use.

Effect on school performance and lifetime achievement

The review indicated that cannabis use impairs critical cognitive functions, both during acute intoxication and for days after use. For this reason, students who smoke cannabis could be functioning at a cognitive level that is below their natural capability for considerable periods of time. However, the results from studies included in the review were inconsistent.

Some studies suggested the long term negative effects of cannabis use on learning may be reversible, whereas others indicated memory and attention got significantly worse the more years someone had been using cannabis regularly.

Some studies suggested early cannabis use is associated with impaired school performance and an increased risk of dropping out of school, but there were other factors that could explain this link. For example, shared environmental factors like growing up in a neighbourhood where drug use is high and academic achievement low.

Risk of motor-vehicle accidents

There were studies indicating that both immediate exposure and long-term exposure to cannabis impair driving ability. According to a meta-analysis, the overall risk of involvement in an accident increases by a factor of about two when a person drives soon after using cannabis. The risk associated with the use of alcohol in combination with cannabis was reported to be greater than that associated with the use of either drug alone.

Risk of lung cancer

The effects of long-term cannabis smoking on the risk of lung cancer are unclear and often complicated by the fact many cannabis smokers also smoke tobacco – which is known to cause cancer. Separating the health effects of the two types of smoking remains a challenge. The researchers warned that the strength of cannabis in circulation is increasing and so any potential risks may also be increasing.

 

Can we believe the review’s findings?

The review’s main weakness is that it didn’t describe how it searched and reviewed the evidence on this subject and whether this was systematic. This means that key evidence may have been missed, leading the authors to potentially draw biased conclusions. It is not possible to say that the results were biased; only that without the methods, there remains a risk that they are.

A second limitation is that the evidence behind the review’s conclusions was drawn largely from early animal studies, or from observational studies that couldn’t establish cause and effect. This means we can’t really make clear cut, definitive statements about the health effects of cannabis use as the evidence, at least the evidence identified in this review, was not strong in most areas. The long term effects of cannabis use, for example, remain in the authors’ words “poorly understood”.

The review generally highlighted a scarcity or lack of knowledge on the beneficial or harmful effects of cannabis. This may be a true reflection of the evidence base, or may be in part because the review has not included all the relevant evidence.

One of the biggest challenges in studying the effects of cannabis is that due to its legal status in much of the world, researchers could not legally use cannabis in the “gold standard” of studies – a randomised controlled trial. There could also be ethical problems in randomly assigning people to use cannabis who don’t already, given its potentially damaging effects.

As more and more parts of the world are now legalising (or at least partially decriminalising) cannabis, research of this type could potentially be carried out and may allow us to learn more about the benefits and risks of this widely used drug.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Smoking marijuana as a teenager lowers IQ for LIFE, scientists warn. Mail Online, June 6 2014

Links To Science

Volkow ND, Baler RD, Compton WM, Weiss SRB. Adverse Health Effects of Marijuana Use. The New England Journal of Medicine. Published online June 5 2014

Categories: Medical News

Sleep 'promotes memory-related brain changes'

Medical News - Fri, 06/06/2014 - 18:19

"The mechanism by which a good night's sleep improves learning and memory has been discovered by scientists," is the somewhat overeager reporting on the BBC News website. While the study had intriguing results, it only involved mice.

This study in mice looked at if and how sleep helps memory and learning. The researchers got mice to perform a running task, running both forwards and backwards on a rotating rod.

Some of the mice were allowed to sleep afterwards and some were sleep deprived. The mice were then microscopically examined to see how sleep, or the lack of it, influenced the connections between the nerve cells in the brain.

Mice who were allowed to sleep experienced the formation of new dendrites (spinous projections at the end of nerve cells), which pass electrical signals from one nerve cell to another.

The formation of new dendrites may be linked to changes in the brain that are associated with learning and experience (changes to the brain's plasticity). But if the mice were deprived of sleep, these new connections did not develop.

The study may not have a direct application to humans, however, and much of the mystery of sleep remains to be discovered. But this research could be another small piece of the puzzle that suggests that sleep is one of the ways we may help consolidate our learning.

 

Where did the story come from?

The study was carried out by researchers from the New York University School of Medicine in the US and Peking University Shenzhen Graduate School in China, and was funded by the US National Institutes of Health, a Whitehall Foundation research grant, and a grant from the American Federation for Aging Research.

The study was published in the peer-reviewed journal, Science Magazine.

The main body of the BBC News reporting is accurate, though the headline "Sleep's memory role discovered" is probably far too definitive for the limited, if interesting, research outlined in the study.

 

What kind of research was this?

This study in mice aimed to see how sleep helps memory and learning. The researchers did this by getting mice to perform a running task. 

Some of the mice were allowed to sleep afterwards, while some were sleep deprived. The mice's brains were then microscopically examined to see how sleep influenced the connections between the nerve cells in the brain.

The researchers say that it is believed that sleep has an effect on the connections (synapses) between nerve cells, which are important for the formation of memories. But the role that sleep plays in learning and experience-dependent changes to the synapses is said to be unclear.

 

What did the research involve?

This study aimed to see how performing a running task remodels the spinous projections (dendrites) that form the connections between nerve cells, and then see how this was influenced by sleep.

A group of mice were trained to run forwards on an accelerated rotating rod. The spinous projections connecting the nerve cells in the brain were microscopically examined before and after the task.

These mice were compared to a group of mice who had not received the rotating rod training. The researchers then looked at the effect of training the mice to run either forwards or backwards on the rod.

After these tests, the researchers examined the potential role of sleep in the process. They compared mice who were allowed to sleep in the seven hours after a period of forward running on the rod with mice who were sleep deprived by continuous gentle handling for seven hours after the task.

They then tested whether the effect of sleep deprivation could be "rescued" by allowing the mice to sleep in the 16 hours after the initial seven hours of sleep deprivation.

 

What were the basic results?

The mice had an increased development of new spinous projections between nerve cells in the brain in the 24 hours after the rotating rod task when compared with mice who had not done the task. 

When they repeated the running task, this time allowing the mice to run forwards or backwards, the researchers found that backwards running led to the formation of a different set of spinous projections.

The researchers then compared mice who were allowed to sleep after the rotating rod task with mice who were sleep deprived. They found that the sleep-deprived mice showed a significantly reduced formation of new spinous projections between nerve cells.

Even if the sleep-deprived mice were allowed to train on the rotating rod for double the amount of time beforehand, it made no difference – they still demonstrated fewer nerve cell connections than the mice who were allowed to sleep.

The 16-hour recovery sleep after the initial deprivation had no effect – they had fewer projections, suggesting the effects of sleep deprivation could not be "rescued".

For mice who had been allowed to sleep, the projections between the nerve cells were demonstrated to persist in the following days, supporting the common understanding that a skill is learned and persists for long periods of time with minimum interference from other learning.

When looking at specific sleep stages, the researchers found that deprivation of REM sleep (the deepest period of sleep in which dreams are thought to occur) in particular did not diminish the synapses. This suggests that non-REM sleep may be involved in forming new nerve connections after learning.

 

How did the researchers interpret the results?

The researchers conclude that their findings indicate that sleep has a key role in promoting learning-dependent connections between nerve cells, which contribute to memory storage.

 

Conclusion

This research in mice furthers our understanding of the important role that sleep plays in consolidating our learning and memory.

When mice learned to run on a rotating rod, the task led to the formation of new spinous projections (dendrites) at the end of nerve cells, which pass electrical signals from one nerve cell to another.

However, if the mice were deprived of sleep, these new connections did not develop.

This effect could not be "rescued", regardless of whether they were allowed to train for a much longer period before being sleep deprived, or if they were allowed to sleep for a long period after their initial sleep deprivation.

The researchers also found that most of the changes to the nerve cell connections seemed to be occurring during non-REM sleep, rather than REM sleep.

The results of this study may not have a direct application to humans. But if further evidence proves that it does, it suggests that attempting to compensate for the adverse effects of missing sleep, such as sleeping for 16 hours after pulling an all-nighter, may be futile: The mice were unable to "rescue" the beneficial effects to the brain if they were sleep deprived for a significant amount of time.

Known harmful effects of not getting enough sleep include:

  • detrimental effects on mood, such as irritability
  • impaired cognitive function
  • increased vulnerability to infection

Read more about Why a lack of sleep can be bad for your health.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Sleep's memory role discovered. BBC News, June 6 2014

Sleep may help memories form by promoting new synapses. New Scientist, June 5 2014

We May Finally Know Why Sleep Improves Memory. Io9.com, June 5 2014

Links To Science

Yang G, Lai CSW, Cichon J, et al. Sleep promotes branch-specific formation of dendritic spines after learning. Science. Published online June 6 2014

Categories: Medical News

5:2 diet style an 'immune booster,' study finds

Medical News - Fri, 06/06/2014 - 14:00

“Fasting for at least two days regenerates immune systems damaged by ageing or cancer treatment, research has shown,” the Daily Express reports. However, the study that is being reported on only involved mice, not humans.

Prolonged or intermittent fasting has become an increasingly popular strategy to achieve weight loss. This has been demonstrated through the incredibly popular 5:2 diet, where participants eat normally for five days a week and then fast for the remaining two.

There have been reports that the 5:2 diet can lead to weight loss for some people, with others claiming that fasting can boost immune function and prevent chronic diseases.

In this study, which used only mice, the researchers aimed to see whether prolonged fasting could reverse the toxic effects of chemotherapy – specifically, damage to white blood cells and bone marrow activity, which leaves the body weakened and vulnerable to infection.

Researchers found that mice fasting for two to five days before being given chemotherapy showed a faster recovery in terms of their white blood cell count. A later-stage clinical trial in humans is reported to be underway.

It is extremely important to stress that if you are undergoing chemotherapy treatment, you should not make any kind of radical changes to your diet unless advised to by your doctor. Doing so could make you vulnerable to complications.

 

Where did the story come from?

The study was carried out by researchers from the University of Southern California, Ohio University and the University of Palermo, in Italy. The study was supported by the National Institutes of Health and Aging and was published in the peer-reviewed science journal Cell. It has been published on an open-access basis, so it is free to read online.

The Daily Telegraph’s reporting of the study was accurate and included discussion from experts, who said that while the findings may have relevance for people receiving cancer treatment, further study is needed, and prolonged fasting should only be considered under the guidance of a doctor. As the Professor of Regenerative Medicine at UCL, Chris Mason, suggests: “The most sensible way forward would be to synthesise this effect with drugs. I am not sure fasting is the best idea. People are better eating on a regular basis.”

The Daily Express’s coverage, while not inaccurate, was not as clear as it should be. It is not until the last part of the article that you realise the study involved mice, not humans.

 

What kind of research was this?

This was a scientific study using mice, which aimed to look at the effect prolonged fasting might have on reversing the toxic effects of chemotherapy.

This included how it affected bone marrow regeneration and circulating white blood cells – key components of the body’s immune system.

The researchers explain how immune system defects are central to the ageing process and are associated with a range of diseases. One of the effects of chemotherapy is DNA damage and cell death, to both circulating blood cells and to stem cells of the bone marrow, which are responsible for producing new blood cells.

This leads to reduced numbers of red blood cells (which carry oxygen), platelets (which help blood to clot) and white blood cells (which make up the body’s immune system), leaving the body weakened and vulnerable to infection.

All of this can result in a wide range of side effects for people undergoing chemotherapy.

The authors state that prolonged fasting for two to five days activates cellular pathways in mice and humans, which enhance the resistance of cells to toxins, such as chemotherapy. Previous studies in mice have found that prolonged fasting leads to this protective effect, by reducing levels of insulin-like growth factor-1 (IGF-1) – a protein involved in growth and development, with a similar function to insulin.

The theory is that the reduction of IGF-1 resulting from prolonged fasting may allow regeneration of stem cells in the bone marrow, and so help to reverse the toxic effects of chemotherapy.

 

What did the research involve?

Mice were divided into two groups who were either fed or fasted prior to being injected with chemotherapy drugs for two weeks. The researchers looked at white blood cell counts during and after chemotherapy treatment, and also assessed DNA damage in circulating blood cells and bone marrow cells.

As their previous study had shown that prolonged fasting leads to a reduction in IGF-1 levels, and they believed that this was responsible for the protection against chemotherapy, they also looked at what would happen when mice genetically engineered to have IGF-1 deficiency were given chemotherapy without having fasted.

 

What were the basic results?

The researchers found that multiple cycles of prolonged fasting protected mice from some of the toxic effects of chemotherapy, reducing DNA damage to both circulating white blood cells and bone marrow stem cells. It also led to the regeneration of bone marrow stem cells. Mice who were given chemotherapy but fed as normal showed prolonged white blood cell depletion, while mice who had fasted beforehand saw their white blood cell count return to normal levels at a faster rate.

As expected, they found that using mice genetically engineered to have IGF-1 deficiency – replicating the effects of prolonged fasting – also showed faster recovery of their bone marrow stem cells. This confirmed that the effect on bone marrow stem cells was probably being mediated by a reduction in IGF-1 levels. Reduction of IGF-1 signalling seemed to promote the renewal of bone marrow stem cells.

 

How did the researchers interpret the results?

The study authors concluded that their results “indicate that cycles of an extreme dietary intervention represent a powerful mean[s] to modulate key regulators of cellular protection and tissue regeneration, but also provide a potential therapy to reverse or alleviate the immunosuppression caused by chemotherapy treatment and ageing”.

 

Conclusion

This scientific study suggests that multiple cycles of prolonged fasting may be able to reverse some of the toxic effects of chemotherapy in mice, by causing the regeneration of stem cells in bone marrow.

This allowed white blood cell counts to return to normal much faster after chemotherapy, compared to mice that were allowed to eat normally.

The study researchers indicated very early-stage study in humans (not appraised here), which found that fasting for 72 hours, rather than 24 hours, in combination with chemotherapy reduced some of the toxic effects of chemotherapy, in line with the findings in mice.

However, the study’s authors acknowledge that these results are very tentative and will need to be confirmed in larger, more robust, human studies.

phase 2 randomised control trial is said to be underway. 

Based on this study alone, it can be stated that people receiving cancer treatment, including chemotherapy, should not fast for extended periods of time without fully consulting a health professional, as this could be damaging to their health in other ways. Appropriate nutrition is very important for people with cancer, during treatment and when recovering from treatment. You should not make any significant changes to your diet without first seeking the advice and guidance of the health professionals treating you.

Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

Going without food for TWO DAYS can regenerate the body. Daily Express, June 6 2014

Fasting for three days can regenerate entire immune system, study finds. The Daily Telegraph, June 6 2014

Fasting 'revives immune system'. MSN News, June 6 2014

Links To Science

Cheng C, Adams GB, Perin L, et al. Prolonged Fasting Reduces IGF-1/PKA to Promote Hematopoietic-Stem-Cell-Based Regeneration and Reverse Immunosuppression. Cell Stem Cell. Published online June 5 2014

Categories: Medical News

Three-person IVF in 'two years'

Medical News - Thu, 06/05/2014 - 16:45

"Scientists will be ready to create babies from three people in around two years, if it is made legal," BBC News reports. The UK fertility regulator, the 

The main conclusion of the review is that the proposed techniques appear to be safe, but there are still a number of experiments that should be performed before treatments are offered to suitable patients.

There would also need to be a change to the law, ratified by parliament, before treatments could be legally offered.

 

What are mitochondrial diseases?

Almost all of the genetic material in our bodies is inside the cell nucleus that contains 23 chromosomes inherited from our mother and 23 inherited from our father. However, there is also a small amount of genetic material contained in cellular structures called mitochondria, which produce the cell’s energy. Unlike the rest of our DNA, this small amount of genetic material is passed to the child only from the mother. There are a number of rare diseases caused by gene mutations in the mitochondria. Women carrying these mutations will pass them directly to their child, with no influence from the father.

The IVF technique being considered aims to prevent these “mitochondrial diseases” by replacing the mother’s mitochondria with healthy mitochondria from a donor, thereby creating a healthy embryo. The child would then have the genetic material of three people – the majority still from the mother and father, but with around 1% of mitochondrial DNA coming  from a donor. 

 

What is mitochondria replacement?

There are two IVF mitochondria replacement techniques currently at the research stage, called pronuclear transfer and spindle transfer. These are the techniques under debate.

Pronuclear transfer involves an egg during the process of fertilisation. In the laboratory, the nucleus of the egg and the nucleus of the sperm, which have not yet fused together (the pronuclei), are taken from the fertilised egg cell containing the “unhealthy” mitochondria and placed into the donor-fertilised egg cell that has had its own pronuclei removed. This early stage embryo would then be placed into the mother’s body. The new embryo would contain the transplanted chromosomal DNA from both of its parents, but would have “donor” mitochondria from the other egg cell.

The alternative mitochondria replacement technique of spindle transfer involves egg cells prior to fertilisation. The nuclear DNA from an egg cell with “unhealthy” mitochondria is removed and placed into a donor egg cell that contains healthy mitochondria and has had its own nucleus removed. This “healthy” egg cell can then be fertilised.

Pronuclear transfer and spindle transfer are said to be potentially useful for the few couples whose child may have severe or lethal mitochondrial disease, and who would have no other option for having their own genetic child. It is estimated that in the UK, around 10-20 couples a year could benefit from these treatments. 

 

How many children does mitochondrial disease affect?

It is estimated that around 1 in 200 children are born each year with some form of mitochondrial disease. Some of these children will have mild or no symptoms, but others can be severely affected – with symptoms including muscle weakness, intestinal disorders and heart disease – and have reduced life expectancy.

 

What ethical concerns have been raised about the techniques?

There are obvious ethical implications from creating an embryo with genetic material from three parents.

Among the questions raised are:

  • Should the details of the donor remain anonymous or does the child have the right to know who their “third parent” is?
  • What would be the long-term psychological effects on the child knowing it was born using donated genetic tissue?

Opponents of these types of treatments cite what can be broadly summarised as the “slippery slope” argument; this suggests that once a precedent has been set for altering the genetic material of an embryo prior to implantation in the womb, it is impossible to predict how these types of techniques might be used in the future.

Similar concerns were raised, however, when IVF treatments were first used during the 1970s; today, IVF is generally accepted.  

Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

Three-person babies 'in two years' - says science review. BBC News, June 3 2014

Three-parent babies 'could be a reality within two years' after report finds controversial IVF techniques are 'not unsafe’. Mail Online, June 3 2014

Three-parent babies ‘safe’ to be born. Metro, June 3 2014

Three-parent babies are 'not unsafe' as human trials planned. The Daily Telegraph, June 3 2014

 

Categories: Medical News

Air pollution linked to irregular heartbeat and lung blood clots

Medical News - Thu, 06/05/2014 - 15:00

"Air pollution is linked to increased risk of developing an irregular heartbeat and blood clots in the lung," BBC News reports.

A large study found that short-term exposure to small particulate matter – a form of air pollution linked to cars and other sources – was linked to a raised risk of death from these conditions.

Small particulate matter is known to potentially be dangerous – because of its size (which can be 100 times thinner than a human hair), it can bypass the body's defences against foreign objects and affect the heart and the lungs.

Reassuringly, though, the study found no clear evidence of a link between air pollution and the risk of having a heart attack or stroke.

But the link found between irregular heartbeats (atrial fibrillation) and blood clots in the lungs (pulmonary embolism) is still a matter of concern. Both conditions can cause serious complications, especially in vulnerable people with a pre-existing health condition.

The study reinforces the fact that we should not become complacent about the health dangers posed by all forms of pollution.

 

Where did the story come from?

The study was carried out by researchers from the London School of Hygiene and Tropical Medicine and was funded by the Department of Health.

It was published in the peer-reviewed medical journal Heart and has been made available on an open access basis, so it is free to read online.

BBC News' and The Guardian's coverage was fair and the BBC included useful comments from independent experts.

 

What kind of research was this?

This study set out to explore the short-term impact of air pollution on cardiovascular disease. Using a case-crossover design, it analysed links between the information taken from three national databases on cardiovascular disease and short-term exposure to various types of air pollution.

The researchers say that high levels of some air pollutants are associated with an increased risk of cardiovascular outcomes, although the mechanism involved is uncertain. 

The study aimed to further our understanding of these mechanisms by examining the relationship between air pollution and a range of cardiovascular events.

 

What did the research involve?

Over the period 2003-09, the researchers used data from three national databases on cardiovascular disease in England and Wales. These included:

  • the Myocardial Ischaemia National Audit Project (MINAP), which tracks hospital admissions for acute coronary syndrome and heart attack (from 2003-09)
  • Hospital Episode Statistics (HES) on emergency admissions (from 2003-08)
  • figures from the Office for National Statistics (ONS) on recorded deaths (from 2003-06)

Using the last two databases, researchers looked at a range of cardiovascular disease events, including heart attacks, all strokes, ischaemic heart disease, chronic ischaemic heart disease, pulmonary embolism, atrioventricular conduction disorders, arrhythmias, atrial fibrillation and heart failure.

Arrhythmia is an abnormality of the heart rhythm and can be dangerous. Atrial fibrillation is a type of arrhythmia where the heart beats very fast and irregularly. A pulmonary embolism is a blockage in the pulmonary artery, which is the blood vessel that carries blood from the heart to the lungs.

The researchers looked at some 400,000 heart attacks, more than 2 million emergency admissions for cardiovascular problems, and 600,000 deaths from cardiovascular disease.

Using data from the monitoring station nearest to where patients lived, they looked at the average levels of air pollutants over a period of five days. Pollutant effects were adjusted for the ambient air temperature – recorded by the UK Meteorological Office – and the day of the week.

The air pollutants included carbon monoxide, nitrogen dioxide, particulate matter (PM10 and PM2.5), sulphur dioxide and ozone. Particulate matter refers to usually invisible particles floating in the air. They can be large (up to 10 micrometers, or PM10) or small (up to 2.5 micrometers, or PM2.5).

In their analysis, the researchers used a case-crossover approach, where the day of each health event was the case and all other days within the same month were controls.

 

What were the basic results?

The researchers found that:

  • The only clear link between deaths from cardiovascular disease and pollution was between PM2.5 particles and deaths from arrhythmias, atrial fibrillation and pulmonary embolism.
  • The pollutant nitrogen dioxide was associated with a raised risk of hospital admission for a variety of cardiovascular events, including cardiovascular disease overall (increased risk from 10th to 90th percentile of 1.7%, 95% confidence interval [CI] I 0.9 to 2.6), non-myocardial infarction cardiovascular disease (2.0%, 95% CI 1.1 to 2.9), arrhythmias (2.9%, 95% CI 0.6 to 5.2), atrial fibrillation (2.8%, 95% CI 0.3 to 5.4) and heart failure (4.4%, 95% CI 2.0 to 6.8).
  • Only nitrogen dioxide was associated with an increased risk of hospital admission for heart attack, of a type called non-ST elevation myocardial infarction (non-STEMI) (3.6% 95% CI 0.4 to 6.9). A non-STEMI heart attack is where the supply of blood to the heart is only partially blocked, rather than completely blocked.  As a result, a smaller section of the heart is damaged and there is a lower risk of fatality.

 

How did the researchers interpret the results?

The researchers say their study found no clear evidence for the effects of pollution on STEMI heart attacks (the most serious type) and stroke, but it did for pulmonary embolism and irregular heartbeat. Lead researcher Dr Ai Milojevic told BBC News that the strongest link was in the over-75s and in women.

They concluded that although it is likely that air pollutants affect cardiovascular health in several different ways, the lack of effects on STEMI heart attacks and stroke suggests it may partly act through "non-thrombotic" pathways – in other words, not through blood clotting.

 

Conclusion

This was a large national study that looked in detail at links between people's short-term exposure to air pollutants and national records on hospital admissions for heart attack, emergency admissions for all cardiovascular problems, and deaths from cardiovascular disease.

The study had some limitations – for example, as the authors say, it did not include heart attacks that took place before hospital admission. It also used fixed monitoring sites, which may not accurately reflect personal exposure to air pollution. 

For the public, the results of this study are probably confusing. That's because the researchers were interested in finding out which particular cardiovascular events are linked to pollution so that they could further understand the ways in which pollutants act on the cardiovascular system.

They found links between pollution and irregular heartbeat and blood clots in the lung – both of which can be dangerous – but not between pollution and heart attacks or strokes.

Most experts believe that pollution – especially small particulate matter – can have an effect on health. It is sensible to avoid areas with severe pollution, especially for those with chronic disease.

You can find updates on air pollution at Defra's UK air information resource pages and from Defra's freephone helpline on 0800 55 66 77. The helpline also offers health advice.

Read more advice about air pollution.


Analysis by Bazian. Edited by NHS Choices
. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Pollution link to irregular heartbeat and lung clotting. BBC News, June 5 2014

Air pollution linked to irregular heart beat, study finds. The Guardian, June 5 2014

Links To Science

Milojevic A, Wilkinson P, Armstrong B, et al. Short-term effects of air pollution on a range of cardiovascular events in England and Wales: case-crossover analysis of the MINAP database, hospital admissions and mortality. Heart. Published online June 5 2014

Categories: Medical News

Cannabis and sunshine may damage sperm quality

Medical News - Thu, 06/05/2014 - 14:25

''Cannabis doubles younger men's risk of infertility, study finds,'' reports The Independent. The same study also found a drop in sperm quality during the summer months.

The paper reported on the results of a study that saw men attending fertility clinics, looking at the effects of lifestyle on one element of male fertility – known as sperm morphology, which refers to the size and shape of sperm.

Sperm with abnormal sperm morphology are less likely to lead to a successful conception.

Researchers found that cannabis use was associated with a higher rate of abnormal morphology – the same trait seen in sperm samples produced during the summertime.

No other lifestyle factors, such as alcohol and smoking, were seen to have an effect.

It is important to point out that only one aspect of sperm quality was analysed. Other aspects, such as sperm motility (how good a “swimmer” each individual sperm is) or sperm count, were not studied.

The study was also reliant on the self-reporting of alcohol, smoking and cannabis use, which is likely to have been underestimated.

Until a more comprehensive look at lifestyle effects on fertility is provided, it is safe to say that choosing a healthy lifestyle is not going to reduce the chances of conceiving and will provide a healthier environment in which to bring up a child.

 

Where did the story come from?

The study was carried out by researchers from The University of Sheffield, the University of Manchester and the University of Alberta, Canada. It was funded by the UK Health and Safety Executive, the UK Department of Environment, Transport and the Regions, the UK Department of Health and the European Chemical Industry Council.

The study was published in the peer-reviewed medical journal Human Reproduction. The article is open access, meaning it is free to view and download online.

The media has largely ignored the fact that this study only looked at the shape of the sperm and not the sperm count, sperm motility or, indeed, fertility itself.

This may give readers the misleading impression that it has been proven that lifestyle factors such as obesity, smoking and excessive alcohol consumption do not have any negative influence on fertility rates. This is definitely not the case.

Read more about the risk factors for infertility.

 

What kind of research was this?

This was a cross-sectional study of men attending fertility clinics to see if there was a link between the shape of sperm (sperm morphology) and lifestyle.

The data came from a large study, which has also looked for links between lifestyle and other measures of sperm quality.

Semen analysis looks at numerous factors such as the acidity, quantity and thickness of the semen, as well as sperm quality.

This is assessed by the morphology, concentration (sperm count) and motility (ability to swim). Previous analysis using the same data set looked at concentration and motility, and did not find any conclusive lifestyle risk factors. This analysis only took the shape into account.

 

What did the research involve?

The researchers recruited 2249 men out of 4257 who had attended fertility clinics in the UK and were eligible for the study. They completed a questionnaire, had an interview on their lifestyle and also undertook a semen analysis. Statistical analysis then looked for links between the lifestyle of those men who had normal-shaped sperm and those who did not.

Men aged 18 and over were recruited to the study from 14 fertility centres in the UK between 1999 and 2002. They were eligible if they had been trying to conceive without success for at least 12 months and had not previously had semen analysis, or did not know the results of any analysis. They also had to understand English.

Exclusion criteria included:

  • having a known medical condition that could cause fertility, such as cystic fibrosis
  • previous treatment than can cause infertility, such as radiotherapy and chemotherapy
  • previous sterilisation of either couple, such as vasectomy or tubal ligation

The men who agreed to take part were given a brief questionnaire to complete at home, which asked about their job, lifestyle and health. They were asked to abstain (from ejaculation) for three to five days and then returned to the clinic. A research nurse then asked further questions about the type of underwear and clothing the person wore, any recreational drug use and fertility history. During the latter part of the study, their body mass index (BMI) was calculated and ethnic group recorded. They were excluded if they did not answer all of the questions.

Semen samples were then analysed. Cases with reduced fertility were defined as having a normal shape in less than 4% of the 200 sperm that were assessed. If there were less than 200 sperm on the slide, they were excluded from the analysis.

They then compared the lifestyle factors of men who had normal shaped sperm in less than 4% of the 200 sperm that were assessed, compared to those who had more than 4% normal-shaped sperm.

 

What were the basic results?

The study recruited 2249 men, representing just over half (53%) of those who were eligible.

Of those recruited, 173 were excluded because:

  • 81 had no sperm on the slide
  • 47 had fewer than 200 sperm on the slide
  • 43 were contaminated
  • 2 were lost

They further excluded all men who were recruited in the first six months of the study, because during this time there was a very high proportion of men with less than 4% of normal-shaped sperm (54.7%) compared to during the rest of the study (16.1%). The researchers did not know why, so excluded them in case they biased the results.

The analysis included 318 men who had less than 4% normal-shaped sperm out of 200, compared to 1970 who did.

Men who used cannabis in the previous three months were more likely to have poor shape than those who didn’t (Odds Ratio [OR] 1.55, 95% Confidence Interval [CI] 1.04-2.30). The effect was greater in men aged 30 or less (OR 1.94, 95% CI 1.05 to 3.60).

Samples collected in the summer were more likely to be reduced shape compared to those collected in the winter (OR 1.99, 95% CI 1.43 to 2.72)

Samples collected after abstinence of more than six days were less likely to be of abnormal shape (OR 0.64, 95% CI 0.43 to 0.95).

No other risk factors had a significant link to sperm shape.

 

How did the researchers interpret the results?

The authors conclude that the study “has identified few modifiable factors associated with poor sperm morphology, with the only practical advice to men attempting conception being to limit exposure to cannabis if they are regular users. We would argue that the results of this study, in combination with our papers that investigated the effect of lifestyle and occupation on poor motile sperm concentrations, suggest that men can make relatively few lifestyle changes to improve semen quality, either to enhance natural conception or improve their chances in assisted conception”.

 

Conclusion

This study has found that the shape of sperm is less likely to be normal when samples are provided in summer and if cannabis has been consumed in the previous three months. It has also found that normal-shaped sperm are more likely to be produced after six days of abstinence. It did not find any other links between lifestyle factors and sperm shape.

The results of this study alone do not show that lifestyle factors other than cannabis are harmless. Male fertility is not just determined by the shape of the sperm; it is also dependent on the concentration, motility and viability of the sperm, as well as the quality of semen. Lifestyle factors could potentially have an effect if they were all combined.

A further limitation of this study, acknowledged by the authors, is that less than half the men attending the fertility clinics met the study's inclusion criteria, and of those who did, only two out of five agreed to participate. The reasons for this are unclear, but could theoretically be because they did not want to disclose their lifestyle.

The men with less than 4% normal sperm shape per 200 were not matched to the “controls” for social and health background data. This is usually conducted so that other confounding factors can be taken into account.

In addition, the study relied on self-reporting in the form of a questionnaire and an interview; it is likely that levels of smoking, alcohol and cannabis use were underestimated.

Whether or not it can be proved that smoking has an effect on fertility, there are many reasons why a potential parent should not smoke. These include the risk of exposure to secondhand smoke for the mother and the risks of a child growing up in a smoking household, such as asthma or even cot death (sudden infant dead syndrome).

Current recommendations on protecting your fertility, such as quitting smoking and moderating your consumption of alcohol, are unchanged.

Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

Cannabis doubles younger men's risk of infertility, study finds. The Independent, June 5 2014

Cannabis cuts men's fertility - but smoking, drinking and wearing tight underwear don't, say scientists'. Daily Mail, June 5 2014

Summer loving may not be recipe for getting pregnant, study finds. The Daily Telegraph, June 5 2014

Links To Science

Pacey AA, Povey AC, Clyma JA, et al. Modifiable and non-modifiable risk factors for poor sperm morphology. Human Reproduction. Published online June 4 2014

Categories: Medical News

'Male hormones' in womb linked to autism

Medical News - Wed, 06/04/2014 - 14:30

“Boys who develop autism may be exposed to higher levels of hormones…in the womb,” The Daily Telegraph reports.

Autistic spectrum disorder (ASD), commonly known as autism, is more common in males, but the reason why is still unknown. One hypothesis is that there may be factors in the development of male infants that increase their risk of ASD, such as exposure to certain hormones.

This study measured sex hormone levels in the amniotic fluid (which surrounds and supports the baby) of over 300 boys. Hormone levels were found to be higher in boys who developed ASD. 

However, this does not necessarily mean this is the cause of ASD. The average levels were higher, but many of the boys who developed ASD had normal and low levels, meaning there has to be other factors that play a role in the development of these conditions.

These findings have no immediate implications.

The researchers argue that even if a higher level is proven in larger studies, and is found to be a causative factor, any attempt to block the effects of hormones using drugs would be unwise, due to the risk of side effects.

This research did not show that the higher levels of the hormones caused ASD, which is still believed to be due to a combination of genetic and environmental factors.

 

Where did the story come from?

The study was carried out by researchers from the University of Cambridge and the Statens Serum Institute Copenhagen. It was funded by the Medical Research Council UK, alongside project grants from Nancy Lurie Marks Family Foundation, Wellcome Trust and the Autism Research Trust. The study was published in the peer-reviewed medical journal Molecular Psychiatry. It has been published on an open-access basis, meaning is free to read online.

The UK media reported the story accurately, apart from the headlines describing the hormones as “male”. All five hormones studied are present in both sexes, and it is only the level of testosterone that is higher in men.

The media acted responsibly by including important commentary from the lead author of the study, Professor Baron-Cohen, clarifying that the study’s results do not mean it would be possible to carry out prenatal tests for ASD or treat the condition in the womb using hormonal treatments.

 

What kind of research was this?

This was a retrospective cohort study, using data from the Danish Historic Birth Cohort.

It aimed to see if there was a link between the sex hormone levels in the amniotic fluid (which surrounds the baby in the womb) and the development of autistic spectrum disorders (ASDs).

This is because ASD is diagnosed much more frequently in males, and previous research has suggested that sex hormones and cortisol affect the developing brain. 

A retrospective cohort study is useful when a randomised controlled trial (RCT) is not possible.

Attempts can be made to account for confounders (other factors that may be causing any effects seen), but there could still be other explanations for the results, so it is difficult to imply direct causation.

 

What did the research involve?

Researchers measured hormone levels in the amniotic fluid samples of boys born between 1993 and 1999. They then compared the levels of hormones in 128 that later developed an autistic spectrum disorder (ASD) with 217 that didn’t (the controls).

The researchers used amniotic fluid samples that had been frozen and stored at -20°C. They used mass spectrometry techniques (where devices are used to analysis the molecular composition of a substance) to measure the level of hormones.

Specifically, cortisol (the stress hormone that is essential for life) and four sex hormones – progesterone, 17α-hydroxy-progesterone, androstenedione and testosterone – were analysed.

The researchers recorded the following potential confounding factors:

  • maternal age
  • paternal age
  • birth weight
  • gestational age (weeks of pregnancy) when the amniotic fluid sample was taken
  • apgar score (indicating the physical health of the newborn immediately after birth)
  • sample storage time

The Danish Psychiatric Register was searched over 2009 and 2010 to identify all diagnosed cases of ASD, according to the WHO-recognised International Classification of Diseases (ICD-10), which were linked with the amniotic samples.

They decided to limit the study to males for two reasons. The first was that when they looked at all samples, there were only 24 girls who developed an ASD, which was deemed to be too small a sample to produce meaningful results. Secondly, there was significant variation in two of the confounding factors between girls who developed ASD and those that didn’t – fathers were significantly older and birth weight was lower, compared to the controls.

Statistical analysis was performed to measure any difference between the two groups and also to account for the confounding factors listed above.

 

What were the basic results?

The average level of each hormone was higher in boys who developed ASD, but the exact measurements were not provided in the study.

All five hormones were of a similar level across the control group. They were also of a similar level in the ASD group, but the mean average was higher than in the control group. The researchers say that this indicates a similar mechanism for the production of these hormones, as there wasn’t one that was substantially higher or lower than any other.

They interpreted that one overall “steroidogenic factor” (a protein that stimulates sex hormone and cortisol production) was significantly higher in the ASD group compared to the control group, and was causing the difference.

There was no statistically significant difference between the groups for any of the confounding factors, and no change to the results when their analysis was adjusted for these factors.

 

How did the researchers interpret the results?

The researchers say this is “the first direct evidence that steroidogenic activity is elevated in fetal development of those who later receive diagnoses on the autism spectrum”.

The researchers are quick to point out that the “source of elevated steroidogenic activity in the fetal development of autism was not tested in the current study, and more research will be needed to understand how different sources – such as the foetus, mother, placenta or other environmental factors – might contribute to such elevations”.

They are also tentative about the elevated level of cortisol seen, stating that: “the current results may suggest a link between [pre-birth] stress and autism via heightened fetal cortisol; however, it is unclear if the association here is due to heightened [pre-birth] stress or is driven by a more primary fetal sex steroid influence that has a side effect of boosting fetal cortisol levels”.

 

Conclusion

This study found that the levels of four sex hormones and cortisol were slightly higher in the amniotic fluid of boys who developed ASD, compared to those who didn’t.

However, this does not necessarily mean it is the cause of ASD. The study accounted for some confounding factors, and the average levels were higher, but many of the boys who developed ASD had normal or low levels. This means that other factors must play a role in the development of the condition.

Although it was a well-designed study, limitations reported by its authors include analysing samples that were over 10 years old, which may have changed over time, despite being frozen at -20°C.

There are no immediate implications for these findings; this is just one part in the long process of figuring out the cause of ASD. It is still believed to be due to a combination of genetic and environmental factors.

The study’s authors were at great pains to stress that using drugs to target sex hormones would be unjustified. Aside from related ethical issues, it is unclear whether such an approach would be safe or effective.

Analysis by Bazian. Edited by NHS ChoicesFollow Behind the Headlines on TwitterJoin the Healthy Evidence forum.

Links To The Headlines

Boys who develop autism 'exposed to higher levels of hormone in the womb'. The Daily Telegraph, June 3 2014

Autism linked to 'male hormones'. BBC News, June 3 2014

Autistic boys exposed to higher levels of hormones in womb, study finds. The Guardian, June 3 2014

Autism linked to higher levels of 'male hormones' in the womb. The Independent, June 3 2014

Links To Science

Baron-Cohen S, Auyeung B,  Nørgaard-Pedersen B, et al. Elevated fetal steroidogenic activity in autism. Molecular Psychiatry. Published online June 3 2014

Categories: Medical News

Centenarians are outliving 'lifestyle' diseases

Medical News - Wed, 06/04/2014 - 14:26

"Centenarians have found a way to beat the common diseases of old age," BBC News reports. A UK study found that the over-100s are less likely to die of diseases associated with lifestyle and more likely to die from infections such as pneumonia.

Over a 10-year period, researchers examined trends in outcomes for centenarians in England, comparing them with younger elderly people who died in their 80s.

They had a particular interest in place of death because this can have an impact on health budgets, as dying in a hospital is often associated with higher costs.

This was intended to inform service provision for centenarians because of the increasing number of people worldwide who are now living beyond the age of 100, which could be as high as around 3 million by 2050.

The study found that centenarians were less likely to die of what are known as non-communicable diseases. These are diseases such as cancer or heart disease that can be caused by unhealthy lifestyle choices, including smoking, obesity and lack of exercise.

But centenarians were found to be more likely to die of diseases that many of us assume are a thing of the past, such as pneumonia.

Ultimately, these findings will be a useful tool for planning future services for people in this age group.

 

Where did the story come from?

The study was carried out by researchers from Kings College London and Sussex Community NHS Trust, and was funded by the National Institute for Health Research.

It was published in the peer-reviewed open access journal, PLOS Medicine, so it is freely available to read online.

The story was covered appropriately by both BBC News and the Daily Mail.

The Daily Express claims that the findings of the study amount to a "scandal". It is hard to see how the newspaper can justify such emotive language.

If anything, the fact that more people are living over 100 is testament to the success of the NHS in improving public health.

 

What kind of research was this?

This was a population-based retrospective observational study comparing place of death and other characteristics.

These characteristics included cause of death for people aged 100 years or older in comparison to a group of younger elderly people over a 10-year period in England.

In an observational study, researchers simply observe groups of people without changing their exposures or circumstances.

A retrospective study relies on data collected in the past, such as from national databases, as was the case in this study. Data collected retrospectively may not be as reliable as data collected prospectively.

However, as the data collected in this study came from national databases, the information is likely to be fairly accurate.

 

What did the research involve?

The researchers included individuals aged 100 years or older at the time of their death who died in England between 2001 and 2010. The only causes of death excluded were accident or violence.

This group was compared with individuals aged 80 to 99 years in the same time period.

The main outcome the researchers were interested in was place of death, which was grouped into five categories:

  • hospital
  • nursing home (defined as providing 24-hour long-term care with nursing)
  • residential care home (defined as providing 24-hour long-term care without nursing)
  • home
  • elsewhere

The researchers used death registration data from England's Office for National Statistics (ONS) from 2001 to 2010 to obtain information about each individual's place of death.

The database was also used to gather information on each person's:

  • age
  • gender
  • marital status
  • usual residence
  • year of death
  • underlying cause of death
  • contributing cause(s) of death

They linked this data with local data on deprivation, settlement type (for instance, urban, town or village), and care home bed capacity. Statistical methods were used to analyse the data.

 

What were the basic results?

There were 35,867 individuals included in this study who were aged 100 years or older (range 100 to 115 years). Most were women (86.75) and most were widowed (85.0%).

The number of centenarian deaths per year in England increased by 56% in 10 years from 2,823 in 2001 to 4,393 in 2010.

The main findings of the study were:

  • most centenarians died in a care home, with 26.7% dying in a nursing home (95% confidence interval [CI] 26.3% to 27.2%) and 34.5% dying in a residential care home (95% CI 34.0% to 35.0%)
  • dying in a hospital was the next most common place of death (27.2%, 95% CI 26.7% to 27.6%)
  • the proportion of deaths in nursing homes (-0.36% annually) decreased over 10 years, while there was little change in hospital deaths (0.25% annually)

Centenarians were more likely to die of:

  • pneumonia (17.7%, 95% CI 17.3% to 18.1%) compared with people aged 80 to 84 years (6.0%, 95% CI 5.9% to 6.0%)
  • old age/frailty (28.1%, 95% CI 27.6% to 28.5%) compared with people aged 80 to 84 years (0.9%, 95% CI 0.9% to 0.9%)

Centenarians were less likely to die from:

  • cancer (4.4%, 95% CI 4.2% to 4.6%) compared with people aged 80 to 84 years (24.5%, 95% CI 24.6% to 25.4%)
  • heart disease (8.6%, 95% CI 8.3% to 8.9%) compared with people aged 80 to 84 years (19.0%, 95% CI 18.9% to 19.0%)

More care home beds being available per 1,000 people was associated with fewer deaths in hospital.

 

How did the researchers interpret the results?

The researchers concluded that centenarians are more likely to have their cause of death certified as pneumonia and frailty, and were less likely to die from cancer or heart disease, compared with younger elderly patients.

They said that reducing reliance on hospital care at the end of life requires recognition of centenarians' increased likelihood to "acute" decline, notably from pneumonia.

They recommend that wider provision of anticipatory care is introduced to enable people to remain in their usual residence, as well as increasing care home bed capacity.

 

Conclusion

This study provides useful information on the place and cause of death of people who live to be 100 years or older compared with a younger elderly population in England. It also provides useful information on trends that have occurred over a 10-year period.

The study's strengths include the large sample of centenarians involved in the research based on data from national registries, which is likely to be reliable.

However, death certificates do not contain information on people's preferences for care in the period before death, so we cannot use the results of this study to draw conclusions about what kind of care this group prefers at the end of life.

Other limitations of this study include that many deaths are classified as being the result of "old age", which may reflect diagnostic uncertainty or limited medical investigations.

The researchers say that certifying death as old age limits the interpretation of the cause of death and therefore the guidance of health services.

But the fact that people who died over the age of 100 were less likely to die from cancer and heart disease than people who died in their 80s is perhaps not so surprising.

Given that these people have lived to such an age suggests that they have not developed these conditions, or if they did they were not associated with mortality.

This may be the result of a wide variety of genetic, socioeconomic, health and lifestyle factors, so this study cannot provide us with any answers about the secret to living beyond the age of 100.

But adopting well-established lifestyle habits such as having a healthy diet, avoiding smoking, taking regular exercise and trying to achieve or maintain a healthy weight certainly won't hurt.

Primarily, these findings will be a useful tool in planning future services for these older populations.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Centenarians 'outliving diseases of old age'. BBC News, June 4 2014

Rise of the 100-year-old puts NHS under strain: Centenarian population expected to hit half a million in 30 years. Daily Mail, June 4 2014

Centenarian death toll is a hospital scandal. Daily Express, June 4 2014

Links To Science

Evans CJ, Ho Y, Daveson BA, et al. Place and Cause of Death in Centenarians: A Population-Based Observational Study in England, 2001 to 2010. PLOS Medicine. Published online June 3 2014

Categories: Medical News