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Updated: 1 hour 18 min ago

Weak link between grandmums' smoking and autistic grandkids

Fri, 2017-04-28 10:30

"Smoking in pregnancy hurts your grandkids by 'increasing their risk of autism'," The Sun brashly reports.

Researchers looked at data spanning multiple generations and reported a link between girls with autism symptoms and having a maternal grandmother who smoked.

They looked at data from more than 14,000 children, which included autism-related behavioural traits, such as poor social communication skills, and whether or not their grandmother smoked in pregnancy.

The results give quite a confusing and mixed picture. Girls whose grandmothers had smoked in pregnancy had increased likelihood of certain traits such as poor social communication skills and repetitive behaviours.

However, this link was only found if the girl's own mother had not smoked in pregnancy. And there was no such link for grandsons, although there was an increased likelihood of grandsons being diagnosed with autism if their grandmother smoked.

The study failed to look at a plethora of other factors that could potentially play a role in autism spectrum disorders. These include parent and child diet, parental alcohol consumption, exercise, weight and genetic influences.

So it's wise to interpret these results with a healthy dose of scepticism – although it remains the case that you should never smoke during pregnancy. Doing so increases the risk of stillbirth, premature birth, and the risk of the child developing asthma in later life.

Read more information about why you should stop smoking in pregnancy.

Where did the story come from?

The study was carried out by researchers from the University of Bristol and was funded by the UK Medical Research Council, the Wellcome Trust and the Escher Family Fund/Silicon Valley Community Foundation.

The study was published in the peer-reviewed journal Nature Scientific Reports, and is open-access, meaning you can read it free online.

The UK media's reporting on the story was generally accurate; making it clear that the study looked at behavioural traits linked to autism and not autism diagnoses as such.

However, it was inaccurate to report that a girl would be "67 per cent more likely to suffer poor social communication skills and repetitive behaviours" if her grandmother smoked during pregnancy. This risk was only found for poor social communication skills.

And as is so often the case, the headlines were far less subtle or precise than the actual reporting, such as The Sun's "GENERATION MAIM Smoking in pregnancy hurts your GRANDKIDS".

What kind of research was this?

This was an analysis of data from a long running UK cohort study of children. Researchers wanted to explore whether a child would be at increased risk of autism if their mother or father had been exposed to their own mother's (the child's grandmother's) smoking during pregnancy.

Autism spectrum disorders (ASD) are long-term developmental conditions characterised by difficulties with communication and social interactions and often a preference for set patterns and routines.

The cause(s) of ASD are not established. Many experts think a combination of genetic and environmental factors may be involved.

This type of research can be informative as it makes use of a very large group of people and can ask multiple questions, including about smoking, and measure multiple health outcomes, including ASD traits.

However, lots of hereditary, environmental and lifestyle factors might contribute to risk of ASD. When the causes are unknown, it is difficult to take all these factors into account and prove that a single one – in this case a grandmother's smoking – causes ASD.

What did the research involve?

The research included a large cohort of 14,062 children from the Avon Longitudinal Study of Parents and Children (ALSPAC) in the UK.

They looked at whether the child's mother or father had been exposed to their own mother's smoking during pregnancy, and whether this child would be at increased risk of ASD.

The researchers looked at certain characteristic traits of ASD, including:

  • Social communication: assessments on a 12-point scale looking at social and communication problems.
  • Repetitive behaviour: looking at mother's response to questions such as 'how often does she/he repeatedly rock his/her head or body for no reason?'
  • Speech coherence: looking at aspects of communication including speech, ability to form sentences, and whether they interpret language too literally.
  • Sociability temperament – looking at four traits: emotional reaction, social interaction with others, shyness and sociability.

They also looked at actual autism diagnosis (diagnostic criteria not described).

They adjusted for the following potential confounders:

  • the year the grandparents were born
  • grandmother's age when the study parent was born
  • number of children the grandparents had
  • sociodemographic factors (e.g. education and occupation)
  • ethnicity
  • sex of the grandchild

They also reported on whether the child's own mother smoked or not during pregnancy.

What were the basic results?

After adjusting for confounding variables, the results showed that maternal grandmother smoking in pregnancy was linked with ASD traits:

  • Social communication: Among maternal grandmothers who smoked in pregnancy, granddaughters were 67% more likely to have a high score (odds ratio (OR) 1.67, 95% confidence interval (CI) 1.25 to 2.25). This was only found when the girl's own mother did not smoke. There was no link for grandsons.
  • Repetitive behaviour: Among maternal grandmothers who smoked in pregnancy, granddaughters were 48% more likely to have a high score (OR 1.48, 95% CI 1.12 to 1.94). This was again only found when their own mother did not smoke, and not in grandsons.

No links were found for speech coherence and sociability temperament.

When combining all grandchildren whose maternal grandmother smoked, there was a 53% increased likelihood of them being diagnosed with autism (OR 1.53, 95% CI 1.06 to 2.20). However, this particular finding was only statistically significant for grandsons.

How did the researchers interpret the results?

The researchers conclude that they found "an association between maternal grandmother smoking in pregnancy and granddaughters having adverse scores in Social Communication and Repetitive Behaviour measures that are independently predictive of diagnosed autism. In line with this, we show an association with actual diagnosis of autism in her grandchildren. Paternal grandmothers smoking in pregnancy showed no associations."

Conclusion

This study aimed to see whether smoking in pregnancy is linked with some traits of ASD in the smoker's grandchildren.

Although this was based on a large cohort of children, the results give quite a confusing and inconclusive picture. To be frank, the study raised more questions than it answered.

Maternal grandmother smoking was linked with ASD traits only in girls (in whom ASD is less common in any case) – and then only if their own mother did not smoke. When looking at actual diagnosed cases of autism, the link was only found in boys.

The study had some important limitations to consider:

  • Most of the data was on behavioural traits, not actual diagnosed ASD, which cannot necessarily be directly linked with autism diagnoses.
  • The causes of ASD aren't known. Although the researchers attempted to adjust for some confounding variables, many other environmental and lifestyle factors could be having an influence, such as the child's or their own parent's diet, exercise or other social influences.
  • ASD traits and autism diagnoses were only found when their own mother had not smoked in pregnancy – which indicates that it might not be smoke exposure that directly increases risk of ASD.
  • The results rely on reports from parents on their own parents, which may have been subject to recall bias if they could not remember all the facts. Some may not have known with certainty if their own parents had smoked during pregnancy.
  • Although it was a large sample, it was not very diverse with most grandparents assessed being of a white ethnic background. This may make findings less relevant to other ethnic backgrounds.

Overall, the mixed findings of this study do not provide any further answers to the causes of ASD.

What is known with certainly is that smoking in pregnancy increases the risk of stillbirth and premature birth, and later in the child's life sudden infant death syndrome and asthma.

Read more advice about quitting smoking if you are planning for a pregnancy, or have become pregnant. 

Links To The Headlines

Smoking in pregnancy hurts your GRANDKIDS by ‘increasing their risk of autism’. The Sun, April 27 2017

Girls are more likely to be autistic if their grandmother SMOKED while they were pregnant. Daily Mail, April 27 2017

Grandmothers who smoked in pregnancy may have triggered autism in granddaughters. The Daily Telegraph, April 27 2017

Smoking grandmothers can pass on autism risk. The Times, April 28 2017 (subscription required)

Links To Science

Golding J, Ellis G, Gregory S, et al. Grand-maternal smoking in pregnancy and grandchild’s autistic traits and diagnosed autism. Scientific Reports. Published online April 27 2017

Categories: News

Binge drinking could trigger abnormal heart rhythms

Thu, 2017-04-27 10:50

"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

Categories: News

New glaucoma test could save millions from blindness

Thu, 2017-04-27 09:30

"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

Categories: News