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NHS Direct Health News

NHS Choices: Behind the headlines   + / -  
last updated: Fri, 28 Apr 2017 08:28:54 GMT

 Thu, 27 Apr 2017 17:50:00 GMT Binge drinking could trigger abnormal heart rhythms

"Why Oktoberfest could be damaging your heart" is the somewhat strange headline in The Times.

Researchers who attended the annual Bavarian beer and folk festival found binge drinkers were more likely to have abnormal heart rhythm patterns.

This could be of potential concern – in extreme cases, abnormal heart rhythms (arrhythmias) can trigger serious complications, such as stroke. No complications of this type were found in the study.

Researchers included more than 3,000 people who attended Oktoberfest in Germany and used a smartphone app to take recordings of the heart, while a breathalyser was used to measure alcohol levels.

The findings were compared with those of another study involving more than 4,000 people believed to represent the general public. 

A novel feature of this approach is it provided "real-time" measurements of alcohol consumption, rather than relying on people recalling how much alcohol they'd drunk, which is often unreliable.

The researchers found binge drinking was linked with an increased risk of having an irregular heartbeat, but this was mainly a type called sinus tachycardia. This is not life threatening, but involves the heart beating at an abnormally fast rate of over 100 beats a minute, which can be very unpleasant.

While these findings do not prove there's a significant link between alcohol and dangerous heart problems, less serious irregularities were found. It's unclear whether this would cause problems further down the line.

To reduce health risks associated with drinking alcohol, government guidelines advise having no more than 14 units a week and spreading your drinking over three or more days if you regularly drink as much as 14 units a week.

Where did the story come from?

The study was carried out by researchers from University Hospital Munich and the German Cardiovascular Research Centre.

Funding was provided by University Hospital Munich and the European Commission's Horizon 2020 research and innovation programme. 

The researchers also used data from the KORA study, which was funded by the Helmholtz Zentrum München, the German Research Centre for Environmental Health, the German Federal Ministry of Education and Research, and the State of Bavaria.

The study was published in the peer-reviewed European Heart Journal.

Generally, the UK media's reporting of the study was accurate. BBC News helpfully explained: "These odds are very low, which meant there was no significant link between alcohol and dangerous heart arrhythmias in the study. But there was a significant link between alcohol consumption and more benign arrhythmias." 

What kind of research was this?

This cross-sectional study aimed to investigate the link between alcohol and having an irregular heart rhythm.

Volunteers at Oktoberfest (who were expected to binge drink to some extent) had their heart rate and rhythm recorded using a smartphone-based electrocardiogram (ECG). The amount of alcohol in their system was measured using a breathalyser.

The researchers contrasted these findings with findings from another study involving people from the general population taking part in a community-based study about long-term diseases.

They also had an ECG, but their alcohol levels were assessed using a questionnaire asking how much they had drunk over the past week.

Acute excessive alcohol consumption, or binge drinking, has been associated with so-called "holiday heart syndrome", which causes irregularities in the heart rhythm in people without any history of cardiac issues.

The researchers thought an increase in breath alcohol concentration would be associated with a higher level of irregular heart rhythms (arrhythmias), and wanted to compare this with day-to-day alcohol intake.

As this was a cross-sectional study where the measurements were only taken at one point in time, this type of study isn't able to prove that alcohol intake causes abnormal heart rhythms.

What did the research involve?

Adults visiting Oktoberfest in Munich between September and October 2015 volunteered to take part in the study as part of the acute alcohol group (people likely to drink a lot in a short space of time).

Participants of the community-based KORA study, Co-operative Health Research in the Region of Augsburg, were also recruited to represent the chronic alcohol group (people likely to drink at an "everyday" level).

Electrocardiogram (ECG) recordings lasting 30 seconds were taken from the acute alcohol group using a smartphone-based AliveCor device.

The device wirelessly communicates with a software application, and was held in both hands by the participant. The KORA group had a 10-second digital ECG.

Two cardiologists, who were unaware which group the participants were in, analysed the ECG recordings to identify and classify the arrhythmias.

To assess alcohol consumption, a handheld device called Alcotest 7510 was used in the acute alcohol group – this accounts for any remaining alcohol in the mouth. The KORA group was assessed using a validated seven-day recall method.

Details of other possible confounding factors were collected:

Acute group (self-reported)

  • age
  • sex
  • country of origin
  • history of heart disease
  • use of cardiovascular and anti-arrhythmic drugs
  • active smoking status

KORA (standardised interview)

  • age
  • sex
  • history of heart disease
  • smoking status
  • diabetes
  • stroke
  • use of cardiovascular and anti-arrhythmic drugs

What were the basic results?

There were 3,028 volunteers in the acute alcohol cohort, with an average age of 34.4 (29% female).

The findings for this group were as follows:

  • average breath alcohol level was 0.85g per kg, considered to be a moderate intake – 3g per kg is considered "disabled due to intoxication" under German law
  • heart arrhythmias occurred in 30.5% of the group – sinus tachycardia, where the heart beats at over 100 beats per minute, occurred in 25.9%; other arrhythmias were present in 5.4% of the group
  • breath alcohol concentration was significantly associated with heart arrhythmias overall, with a 75% increase in the chance of having a heart arrhythmia for each additional 1g per kg of breath alcohol (odds ratio [OR] per unit change 1.75, 95% confidence interval [CI] 1.50 to 2.05)
  • each increase in breath alcohol of 1g per kg doubled the risk of  sinus tachycardia (OR 1.96, 95%CI 1.66 to 2.31)

There were 4,131 people in the KORA group, with an average age of 49.1 (51% female). The findings were:

  • average alcohol consumption was 15.8g per day, equivalent to about 2 units
  • each additional 1g per kg consumed was associated with increased risk of sinus tachycardia – but this increase was quite small (OR 1.03, 95%CI 1.01 to 1.05)

How did the researchers interpret the results?

The researchers concluded that acute alcohol consumption is associated with heart arrhythmias and sinus tachycardia in particular.

They say this may lead to more serious heart rhythms problems, such as atrial fibrillation, though this was only present in less than 1% of each group.

The researchers also didn't follow the people over time to see who developed more serious arrhythmias that could lead to further complications.

Conclusion

This cross-sectional study found binge drinking is associated with an increased risk of having an irregular heartbeat.

However, the type of irregular heartbeat found was mainly sinus tachycardia, which isn't life threatening but involves the heart beating at an abnormally fast rate of over 100 heartbeats a minute.

This research also has some notable limitations:

  • The ECG recordings from the acute alcohol group were taken using a smartphone application operated outside the manufacturer's recommended environment. The lively atmosphere within the beer tent may have caused inaccurate recordings.
  • The population recruited from Oktoberfest was varied in ethnic origin and only 69% were from Germany – it may not be appropriate to compare them with the KORA community population, where more than 99.5% were of German descent.
  • The volunteers in the acute alcohol group were self-selected and might not be representative of the average binge drinker in terms of potential confounding factors like health background. They also provided details of their age, sex, heart disease history and use of heart medications, which may not be accurate because of recall bias and alcohol consumption.
  • But the main limitation is the study design – cross-sectional studies cannot prove cause and effect. 

These findings do not prove there is a significant link between alcohol and dangerous heart arrhythmias, but the researchers did find less serious heart irregularities.

To reduce the risk of any health risks associated with drinking alcohol:

  • drink no more than 14 units a week on a regular basis
  • spread drinking over at least three days a week if you regularly drink 14 units a week

Better still, cut down and aim to have several alcohol-free days a week.  

Links To The Headlines

Why Oktoberfest could be damaging your heart. The Times, April 26 2017 (subscription required)

How binge drinking disrupts your heartbeat: Consuming large amounts found to cause an irregular rhythm that can lead to serious health problems in later life. Mail Online, April 26 2017

Alcohol binge can upset heart's rhythm, say researchers. BBC News, April 26 2017

Links To Science

Brunner S, Herbel R, Drobesch C, et al. Alcohol consumption, sinus tachycardia, and cardiac arrhythmias at the Munich Octoberfest: results from the Munich Beer Related Electrocardiogram Workup Study (MunichBREW). European Heart Journal. Published online April 25 2017

 Thu, 27 Apr 2017 16:30:00 GMT New glaucoma test could save millions from blindness

"It might be possible to treat the main cause of permanent blindness before people notice any loss of vision," BBC News report.

A proof of concept study of early testing for glaucoma – the most common cause of sight loss – had promising results.

In glaucoma, the light-sensitive cells of the retinal nerve die, usually because of increased pressure in the eye. The damage to the nerve, which is irreversible, causes progressive loss of vision. Because people with glaucoma often don't have symptoms in the early stages of the disease, a lot of damage may be done before it is picked up. Diagnosing glaucoma early would allow earlier treatment to relieve pressure in the eye, and may prevent sight loss.

The new technique involves injecting people with a fluorescent dye (thankfully into the bloodstream, not the eye), and taking images of the eye. Dying retinal nerve cells show up as white spots on the image.

Researchers compared images from eight people with early glaucoma and eight healthy people, and showed that white spots were more than twice as common in people with glaucoma. They also seemed more common in people whose glaucoma got worse quickly over time.

However, the technique needs to be tested in large-scale studies to confirm the result as well as find out more about any safety issues.

The study reinforces the importance of having regular eye tests as these can often pick up glaucoma before it becomes a significant problem. You should have an eye test at least every two years.

 

Where did the story come from?

The study was carried out by researchers from Western Eye Hospital, Imperial College and University College London and was funded by the Wellcome Trust. The study was published in the peer-reviewed journal Brain on an open-access basis so it is free to read online.

BBC News, ITV News and The Daily Telegraph all covered the story. Their reports were mostly accurate and balanced, although none made clear the amount of research that still needs to be done before the new test can be put into use.

 

What kind of research was this?

This was an open labelphase one clinical trial designed to establish proof of concept. Trials of medicines and tests go through three phases to ensure they are safe and effective.

The study was the first done in humans, so researchers wanted to know if it worked, if it caused any adverse effects, and what effect different doses of the dye had. They will now need to do phase 2 and phase 3 trials on much bigger groups of patients to confirm their initial results.

 

What did the research involve?

Researchers recruited eight healthy adults without eye disease and eight adults being treated for early glaucoma at the hospital, with no other eye disease. People had an injection of the fluorescent dye (one of four different doses) then had their eye scanned by an infrared laser ophthalmoscope. The researchers assessed the images and compared those from healthy people and people with glaucoma.

Everyone was given a full eye examination when they were recruited, on the day of the test, and 30 days later. They were monitored for adverse events from the injection for six hours, with a phone call 24 hours later.

Researchers also looked to see what happened to the people with glaucoma during their future clinical follow-up visits, for up to 16 months. They then looked to see if the test results predicted how their glaucoma progressed.

 

What were the basic results?

Participants with glaucoma had on average more than twice as many white spots showing dying nerve cells as people with healthy eyes (2.37-fold increase, 95% confidence interval 1.4 to 4.03).

People with glaucoma whose disease got worse over the following months also had more white spots than those whose disease stayed the same. Among people without eye disease, older people had more white spots.

Glaucoma is more common among people aged over 75.

No-one had major side effects linked to the injection (one person found it painful and one person had a bruise afterwards).

 

How did the researchers interpret the results?

The researchers stress their results need to be confirmed by bigger trials, saying: "Like any new technology," it will "need robust testing if it is to be successfully validated."

However, they say, it might be possible to use the test "as a method of detection and monitoring of patients" with glaucoma. They say they have shown that the technique may be useful for identifying nerve degeneration.

They further theorise that it might one day be used for other diseases, including the eye disease macular degeneration, optic neuritis (inflammation of the optic nerve) and "Alzheimers-related disease."

 

Conclusion

Glaucoma is responsible for about 10 in 100 people registered blind in the UK. About 2 in 100 people over 40 in the UK have glaucoma, and around 10 in 100 of those aged over 75. Because there is no cure, but early treatment can often help slow or prevent damage, early diagnosis is important.

Regular eye tests may pick up glaucoma, but often there's no sign of the disease until people have already begun to lose vision. That's why this test is interesting. If it can be shown to work well and safely, it could be a quick and efficient way to diagnose glaucoma before people have started to lose their sight. However, there's more work to do before we get to that stage.

The initial trial results in 16 people need to be repeated among bigger groups, to be sure the results hold true. The researchers need to establish the best dose of the fluorescent dye. Importantly, they need to establish what number of white dots is normal, and what number suggests early glaucoma. This research only shows that people with glaucoma had more white dots, not what would be a good cut-off point for early diagnosis.

Everyone should have a routine eye test at least every two years. This may include a test for high pressure in the eye, as well as a sight test.

If a close relative has glaucoma, mention it to the optician to be sure they carry out appropriate checks. Some types of glaucoma can run in families, so if you do have a family history, more frequent tests may be recommended. 

Links To The Headlines

Test may spot glaucoma before symptoms begin, study says. BBC News, April 27 2017

New glaucoma test 'means treatment can start before sight loss symptoms begin'. The Daily Telegraph, April 27 2017

New test could detect glaucoma before symptoms begin. ITV News, April 27 2017

Links To Science

Cordeiro MF, Normando EM, Cardoso MJ, et al. Real-time imaging of single neuronal cell apoptosis in patients with glaucoma. Brain. Published online April 26 2017

 Wed, 26 Apr 2017 17:30:00 GMT Regular exercise for the over-50s 'sharpens the mind'

"Doing moderate exercise several times a week is the best way to keep the mind sharp if you're over 50," BBC News reports.

A review of existing data found both aerobic exercise and strength training appeared to improve cognitive functions, such as memory, attention, and how well people carry out tasks. 

The review brought together information from 39 studies in the biggest summary of the effects of exercise on mental ability to date.

Previous summaries of research have had unclear results. But this study found most types of moderate to vigorous exercise had a positive effect as long as sessions lasted at least 45 minutes.

The researchers say doctors should recommend people take part in exercise on as many days a week as possible.

Importantly, the study found people benefited even if they were already showing signs of mental decline. This means exercise might help those with early signs of dementia stay mentally alert for longer.

The study provides yet another reason to keep active in later life – both the mind and the body should benefit.

It's recommended that adults do at least 150 minutes of exercise a week, ideally through a combination of aerobic and strength training exercises.

Where did the story come from?

The study was carried out by researchers from the University of Canberra and Australian National University, both in Australia. No funding information was provided. 

It was published in the peer-reviewed British Journal of Sports Medicine on an open access basis, so it's free to read online.

The study was widely reported, with somewhat conflicting and inaccurate advice in the headlines.

The Daily Telegraph and the Daily Express say people only need exercise for 45 minutes a week, although most of the studies included exercise programmes twice a week or more.

The Sun says "walking benefits the brain more than cycling" – but the study didn't present any evidence for this.

The intensity rather than the type of exercise was important, so moderate-intensity cycling should be as good as moderate-intensity walking or running.

What kind of research was this?

This was a systematic review and meta-analysis of randomised controlled trials (RCTs) of exercise programmes.

A meta-analysis of RCTs is a good way to summarise and pool evidence to show whether a particular intervention (in this case, exercise) affects a particular outcome (in this case, cognitive function).

What did the research involve?

Researchers looked for any RCTs that compared an exercise programme with a control group, among adults over 50 living at home, with at least one test of cognitive function (mental ability) as an outcome.

They excluded studies where exercise was not the only intervention – for example, exercise plus brain training – to focus the study on exercise alone.

They then pooled the results between exercise groups and control groups to find the standard mean difference from baseline cognitive function.

Researchers also analysed the results by:

  • type of exercise (aerobic, resistance/strength training, a combination of the two, yoga and tai chi)
  • intensity (low, moderate or high)
  • duration of exercise session (less than 45 minutes, 45 minutes to an hour, more than an hour)
  • length of programme (4-12 weeks, 13-26 weeks, more than 26 weeks)
  • frequency of exercise sessions (two or fewer, 3 or 4, 5-7)

Tests of cognitive function included overall cognition, attention (such as ability to process information quickly), executive function, long-term memory, and short-term working memory.

All the studies were assessed for risk of biases, such as publication bias. The researchers did not exclude any studies based on the date of publication or type of exercise.

What were the basic results?

The study found, overall, taking part in an exercise programme had a small to moderate positive effect on cognitive function, although this varied considerably from one study to another.

People's mental abilities at the start of the study made no difference to the results – people were likely to benefit even if they already showed signs of mild cognitive decline.

Looking at the different types of exercise separately, the authors found:

  • all types of exercise studied except yoga showed a positive effect on cognitive function
  • aerobic and resistance training (such as weight training) showed similar effects, suggesting that both types of exercise are important
  • studies where exercise duration was 45 minutes to an hour showed better results than shorter or longer exercise sessions
  • all lengths of exercise programme, and programmes with all frequencies of sessions, had a positive effect – there were no clear differences between them
  • moderate and vigorous exercise showed better results than low-intensity exercise

The type of control group made a difference. Where people in the control group had either no intervention or a sedentary intervention (such as attending lectures or a computer course) the difference in cognitive function compared with exercise was notable.

However, when the control group did stretching exercises or attended social events, the difference was small enough that it could have been down to chance – in other words, it wasn't statistically significant.

The quality of the evidence was assessed as "moderate" overall. It's not possible to blind people in exercise studies as to whether or not they're doing exercise, which means the studies all have a risk of bias from people knowing whether or not they're being treated.

How did the researchers interpret the results?

The researchers say their findings "suggest that an exercise programme with components of both aerobic and resistance-type training, of at least moderate intensity and at least 45 minutes per session, on as many days of the week as possible, is beneficial to cognitive function in adults aged more than 50 years".

They say future studies should accept as a starting point that exercise is beneficial, and concentrate on ways to "refine the prescription" to identify the best exercise programme to benefit brain function.

Conclusion

It's no surprise to hear that exercise has health benefits – but not everyone knows that it's good for your brain as well as your body.

This study provides evidence that, even for people with some signs of declining mental function, regular moderately intense exercise has a positive effect.

There are a few minor caveats, however. Although the study showed tai chi is beneficial, this was based on only four trials.

And it's not completely clear how often people need to exercise. The study found any number of weekly sessions showed a benefit, but it's reasonable to think more sessions would be more beneficial.

The reasons why physical exercise benefits mental function are thought to include better blood flow to the brain, which keeps nerve cells healthy and supplied with oxygen, lower inflammation and less cellular damage.

Current guidelines for exercise for adults in the UK are to do at least one of the following:

  • 150 minutes of moderate aerobic activity, such as cycling or fast walking, every week, and strength exercises on two or more days a week that work all the major muscles (legs, hips, back, abdomen, chest, shoulders and arms)
  • 75 minutes of vigorous aerobic activity, such as running or a game of singles tennis, every week, and strength exercises on two or more days a week
  • a mix of moderate and vigorous aerobic activity every week (two 30-minute runs plus 30 minutes of fast walking equates to 150 minutes of moderate aerobic activity) and strength exercises on two or more days a week

Other ways you can reduce your risk of dementia include:

Links To The Headlines

Exercise 'keeps the mind sharp' in over-50s, study finds. BBC News, April 25 2017

Doctors should prescribe exercise to the over-50s to 'help prevent dementia' as walking 'benefits the brain more than cycling'. The Sun, April 24 2017

45 minutes' exercise a week boosts brain power in over-fifties. The Daily Telegraph, April 24 2017

45 minutes of exercise for over-50s can 'significantly' improve brain function, study finds. Daily Mirror, April 24 2017

Exercise keeps dementia at bay: Running and walking 'significantly' boosts brain power. Daily Express, April 24 2017

Links To Science

Northey JM, Cherbuin N, Pumpa KL, et al. Exercise interventions for cognitive function in adults older than 50: a systematic review with meta-analysis. British Journal of Sports Medicine. Published online April 24 2017


 

 
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