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Research

Alcohol consumption and risk of dementia: 23 year follow-up of Whitehall II cohort study

BMJ 2018; 362 doi: https://doi.org/10.1136/bmj.k2927 (Published 01 August 2018) Cite this as: BMJ 2018;362:k2927

Opinion

The role of health behaviours in cognitive ageing

Re: Alcohol consumption and risk of dementia: 23 year follow-up of Whitehall II cohort study

I thank the authors of “Alcohol consumption and the risk of dementia: 23 year follow up of the Whitehall II cohort study” published in the BMJ on the 1st of August 2018 for their interesting, albeit highly controversial, findings that suggest that starting from mid-life moderate drinkers have a reduced risk of developing dementia.

It should be noted that there is a broader public health and societal significance to the author’s findings. In Australia, dementia is the second leading cause of death while in the United Kingdom there are 850,000 people living with dementia and the deterioration in quality of life it causes. (1) (2) Dementia is also a group of diseases which conjure up feelings of angst and fear in many people. The loss of control and profound impairment in the later stages of the disease place an undue and overwhelming burden on the patient as well as their support network leading to the apprehension often seen towards the disease in the community. It is within this context of public health concern and societal unease that the author’s findings have been published.

There will always be substantial interest from the general public in research that presents ideas about health issues that concern a broad segment of society. This article is no exception. Coverage of this article’s findings in the media has been extensive both domestically and internationally. Unfortunately, this has led to news headlines such as ”Moderate drinkers are less likely to get dementia than teetotallers” run by The Times and “Middle age non-drinkers may have “higher risk of dementia” in The Guardian which seize upon one part of the research to present an appealing albeit distorted view of the findings and their implications for clinical practice. (3) (4) As a result, the potential for misunderstanding by the general public of the article’s conclusions is rife and it is a shame that the article’s more important observation about the substantial increased hazard posed by heavy drinking did not receive greater publicity. While it is not the fault of the author’s that this has occurred nor a problem confined to their research, there should be concern about the impact that this type of headline and coverage has upon the public’s health knowledge.

This article is part of a diverse, lively and divisive debate about alcohol and brain function. In particular, it contradicts the findings of an article published by this journal in 2017 which used the same dataset (but with different study design) to conclude that light or moderate drinking does not have a protective factor against cognitive decline. (5) Therefore, this article should not be looked on in isolation but as part of a mosaic of findings that will, with additional research, come together to create a complete picture of the impact of alcohol on dementia. The findings about the risk of dementia in alcohol abstainers should also be viewed within the framework of the strong evidence for the linear negative effects of increased alcohol consumption on the incidence of cancer, liver disease and accidental injury which led the United Kingdom’s Chief Medical Officers’ to advise that even drinking within the recommended limits carried a low but present risk of harm with uncertain benefits. (6) Caution must, therefore, be advised to anyone who wishes to point to this article, despite the author’s full disclosure of its limitations, as the next clinical practice panacea for preventing dementia.

References:

1. Alzheimer’s Society (UK). Facts for the media London, United Kingdom: Alzheimer’s Society (UK); 2018 [Available from: https://www.alzheimers.org.uk/about-us/news-and-media/facts-media ] [Accessed 3rd of August 2018].
2. Dementia Australia. Dementia statistics North Ryde, New South Wales, Australia: Dementia Australia; 2018 [Available from: https://www.dementia.org.au/statistics ] [Accessed 3rd of August 2018].
3. Lay K. Moderate drinkers less likely to get dementia than teetotallers. The Times 2018 [Available from: https://www.thetimes.co.uk/article/moderate-drinkers-less-likely-to-get-... ] [Accessed 3rd of August 2018].
4. Greenfield P. Middle-aged non-drinkers may have 'higher risk' of dementia. The Guardian 2018 [Available from: https://www.theguardian.com/society/2018/aug/01/middle-aged-non-drinkers... ] [Accessed 3rd of August 2018].
5. Topiwala A, Allan CL, Valkanova V, et al. Moderate alcohol consumption as risk factor for adverse brain outcomes and cognitive decline: longitudinal cohort study. The BMJ 2017;357(2353) DOI:: 10.1136/bmj.j2353
6. Department of Health (EN), Welsh Government, Department of Health (NI) and Scottish Government. UK Chief Medical Officers’ Low Risk Drinking Guidelines. London, United Kingdom, 2016.

Competing interests: No competing interests

03 August 2018
Gabriel L. Van Duinen
Student (Public Health: Policy and Promotion)
Macquarie University
4 Eastern Road, North Ryde New South Wales 2113, Australia