May 19, 2021

expert reaction to a preprint looking at alcohol consumption and brain health

A preprint, an unpublished non-peer reviewed study, uses UK Biobank data to look at alcohol consumption and brain health.

Dr Katy Jones, Assistant Professor of Applied Psychology, University of Nottingham, said:

“This is an important and high-quality piece of work that challenges the idea of a ‘J-shape’ curve for alcohol consumption and health. Along with the large sample size and robust analysis, two methodological strengths stood out. First, this study provides a more nuanced definition of people who do not drink by dividing into former and never drinkers. Although, more work is needed to truly understand these groups. Second, participants were given clear guidance about how many UK alcohol units are in their drinks (e.g., a ‘standard’ glass of red or white wine contains 1.7 units). Wine strength and glass size have increased over time; thus, we mustn’t assume 1 unit= 1 glass of wine as this can lead to underreporting of alcohol consumption. The study shows the way we drink seems to be important with a ‘binge’ style of drinking having negative effects on the brain. In general, the study highlights we need more education on how we define binge drinking in practical terms. For example, glass size, the strength of the alcohol consumed, how many drinks are being consumed in one sitting, and how many times a week this behaviour is repeated. We need to move away from the idea of ‘binge drinking’ being a way that young people drink and consider how often this behaviour occurs across different age groups.”

Dr Sadie Boniface, Head of Research, Institute of Alcohol Studies and Visiting Researcher, King’s College London, said:

“This study looks at associations between alcohol consumption and grey matter volume in the brain. The authors say they have adjusted for confounders in the relationship and discuss limitations of their research in the paper, but this is still a pre-print, meaning it is yet to be peer-reviewed by experts in the field.

“While we can’t yet say for sure whether there is ‘no safe level’ of alcohol regarding brain health at the moment, it has been known for decades that heavy drinking is bad for brain health. We also shouldn’t forget alcohol affects all parts of the body and there are multiple health risks. For example, it is already known there is ‘no safe level’ of alcohol consumption for the seven types of cancer caused by alcohol, as identified by the UK Chief Medical Officers.

“It is important that the public are made aware of health risks linked to alcohol. The forthcoming consultation on alcohol labelling will provide a real opportunity to introduce independent health information on alcohol products so that so consumers can make fully informed decisions about their drinking.”

Dr Rebecca Dewey, Research Fellow in Neuroimaging, University of Nottingham, said:

“Just from an initial read, yes the data looks like it backs up the claims. As with all biobank studies, as there was no initial hypothesis regarding alcohol, and participants were self-selecting and likely to be from the healthiest, best-educated, and more privileged sectors of society. It is also famously not ethnically diverse. Therefore some caution is needed, but the extremely large sample size makes it pretty compelling.

“It looks like the confounding factors all come out in the wash with such large numbers, and have been taken into account wherever possible – the only confound I worried about at a first glance is that of such a small proportion of the current drinkers having less than A-level or equivalent qualifications, but that would work in the opposite direction to the main findings if it were a confound. The finding about blood pressure exacerbating the effect of alcohol may be a little circular as the drinkers had a slightly higher blood pressure than never/former drinkers, but well within the error bars for a sample that size.

“We don’t know the degree to which very small changes in brain volume are harmful. While there was no threshold under which alcohol consumption did not cause changes in the brain, there may a degree of brain volume difference that is irrelevant to brain health. We don’t know what these people’s brains looked like before they drank alcohol, so the brain may have learned to cope/compensate.

“Theoretically, if the government wanted to, on the basis of this research, they would change the lowest risk advice to be do not ever drink rather than saying any particular amount is “safe”, particularly for those with high blood pressure and BMI, and to reinforce the message of cutting out binge drinking (which I think is already relatively clear).

“While I don’t think it is overspeculated, it is an incremental addition to the knowledge in the area, and probably no great surprise to anyone in the area.”

Prof Paul M. Matthews, Edmond and Lily Safra Chair, NIHR Senior Investigator, and Head of the Department of Brain Sciences, Imperial College London, Said:

“This carefully performed preliminary report extends our earlier UK Dementia Research Institute study of a smaller group from same UK Biobank population also showing the even moderate drinking is associated with greater atrophy of the brain, as well as injury to the heart and liver.  The authors’ concerns that there is not a “safe threshold” below which there are no toxic effects of alcohol echoes our own.  We join with them in suggesting that Current public health guidelines concerning alcohol consumption may need to be revisited.”

Previous papers from our group that also might interest journalists are:

Alcohol consumption is associated with structural changes in various organ systems: A population-based study in UK Biobank (https://www.medrxiv.org/content/10.1101/2021.01.20.21249931v1)

Associations of Regional Brain Structural Differences With Aging, Modifiable Risk Factors for Dementia, and Cognitive Performance (https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2757375

‘No safe level of alcohol consumption for brain health: observational cohort study of 25,378 UK Biobank participants ‘ by Anya Topiwala et al. is a preprint available on medRvix

https://www.medrxiv.org/content/10.1101/2021.05.10.21256931v1

Declared interests

Dr Sadie Boniface: “I work at the Institute of Alcohol Studies which receives funding from the Alliance House Foundation.”

None others received.