While there is general agreement that the moderate intake of alcohol is associated with a significantly lower risk of cardiovascular disease, there are less data on the relation of moderate alcohol consumption to dementia. However, the vast majority of well-done prospective studies indicate that, in comparison with non-drinkers, moderate, non-binge-drinking older adults have lower risk of Alzheimer Disease and other types of dementia. The present study provides important information on this association by monitoring for the development of dementia among subjects in a large cohort of British civil servants (the Whitehall Study) over more than two decades; there were repeated assessments of alcohol consumption.
The main results indicate that abstinence in middle life is associated with a significantly higher risk of dementia than the risk among moderate drinkers, while subjects reporting the intake of larger amounts of alcohol or evidence of an alcohol use disorder are at increased risk of dementia. Specifically, the study shows that among the 397 cases of dementia that were recorded over a mean follow up of 23 years, abstinence in midlife was associated with a 47% higher risk of dementia compared with consumption of 1-14 units/week (a British unit is the equivalent of 8 grams of alcohol). There was a 17% increase in risk of dementia for those reporting more than 14 units/week. With repeated assessments of alcohol the authors also calculated trajectories of alcohol consumption from midlife to early old age, with continued abstinence being associated with an increase in dementia of 74% and a decrease in consumption with an increase of 55% in comparison with subjects reporting continued moderate consumption. In several analyses, wine consumption was associated with more favorable effects than those of other beverages.
Forum members thought that this was a well-done analysis, but considered that the data presented do not allow for a firm determination of a cut-point for increased risk of dementia from alcohol intake. While the authors provide estimates of a linear increase in dementia risk for subjects reporting more than 14 units/week or reporting evidence of alcohol abuse, they do not give data that permits an estimate of the level of intake where the risk of dementia exceeds that of non-drinkers.
Overall, the results showing a decreased risk of dementia for moderate drinkers support the findings from most well-done prospective cohort studies. As for implications for policy, the study further shows that, in terms of the risk of dementia as well as cardiovascular disease, middle-aged and older individuals who are consuming alcohol moderately and without binge drinking should not be advised to stop drinking.
Reference: Sabia S, Fayosse A, Dumurgier J, Dugravot A, Akbaraly T, Britton A, Kivimäki M, Singh-Manoux A. Alcohol consumption and risk of dementia: 23 year follow-up of Whitehall II cohort study. BMJ 2018;362:k2927. http://dx.doi.org/10.1136/bmj.k2927