Cognitive Effects of Moderate Alcohol Consumption

Several studies suggest that moderate drinking may reduce the risk of cognitive decline associated with aging and dementia, including Alzheimer disease. To assess the effect of alcohol on cognitive dysfunction (defined as scoring in the lowest quintile on tests of cognitive functioning), researchers evaluated approximately 11 years of follow-up data on 6033 men and women (aged 35–55 years at baseline and 46–68 when cognition was assessed) in the United Kingdom. Results from analyses adjusted for potential confounders (e.g., age, smoking, socioeconomic status, cholesterol and blood pressure levels) include the following:

• On most measures (tests of verbal and mathematical reasoning, verbal fluency, and verbal meaning), men who consumed >241 g of alcohol per week (over 3 standard drinks per day), compared with men who consumed <1 g per week, experienced significantly lower odds (odds ratios, ORs, from 0.5 to 0.6) of cognitive dysfunction (with borderline significant findings on the test of memory).
• Female drinkers experienced significantly lower odds of dysfunction on tests of verbal meaning (ORs from 0.3 to 0.6 at amounts <=160 g per week) and on one measure of verbal fluency (OR 0.5 at 49–80 g per week).
• More frequent drinkers usually had the lowest odds of cognitive dysfunction on most measures. Lifetime abstaining men and women (compared with occasional and moderate drinkers) generally had higher odds.

Comments:

This study is consistent with prior studies showing the possible benefits of moderate drinking on cognition in middle-aged adults. The mechanisms of protection against cognitive dysfunction are unknown, but may relate to decreased cerebral vascular disease and/or increased cerebral blood flow associated with moderate alcohol consumption.

R. Curtis Ellison, MD

Reference:

Britton A, Singh-Manoux A, Marmot M. Alcohol consumption and cognitive function in the Whitehall II Study. Am J Epidemiol. 2004;160(3):240–247.
(view abstract)