A number of epidemiologic studies have found that lower-risk alcohol intake may be associated with a decreased risk of developing dementia and/or cognitive decline, while heavy consumption may increase the risk. This meta-analysis was based on data from 11 studies with 4586 cases of all-cause dementia diagnosed among >70,000 participants—plus 2 additional analyses of studies of approximately 50,000 participants each—and evaluated the association of alcohol intake with the diagnosis of Alzheimer’s disease and vascular dementia. Seven studies provided results according to type of alcohol consumed, while 2 provided results according to APOE-4 levels.
- “Light-to-moderate” alcohol consumption* was associated with lower risk of all types of dementia (including vascular dementia and Alzheimer’s disease).
- There was a non-significant association with increased risk of dementia for consumers of >38 g alcohol/day (about 3–4 typical drinks).
- Beverage-specific analyses indicated that the effect was only for wine, not for beer or spirits. For people with “moderate” wine consumption, the risk of dementia was reduced by ≥40% compared with non-drinkers.
- The presence or absence of APOE-4 did not appear to modify the risk.
* Alcohol consumption was qualitatively defined as: light (<7 drinks/week), light-to-moderate (<14 drinks/week), moderate (7–14 drinks/week), moderate-to-heavy (>7 drinks/week), and heavy (>14 drinks/week), with one drink = ~12 g alcohol.
Comments: The authors were unable to include the pattern of drinking and could not test for previous alcohol consumption among people currently without alcohol use. Overall, the results support a J-shaped curve between alcohol consumption and dementia, with effects primarily from wine. While mechanisms for such an effect are not well defined, in experimental studies both alcohol and polyphenols in wine have been shown to decrease atherosclerosis and favorably affect hematological factors (for cerebral as well as coronary arteries). Further, both alcohol and wine have been shown to have anti-inflammatory effects and direct effects on brain structures that could relate to lower risk of dementia.
R. Curtis Ellison, MD
Reference: Xu W, Wang H, Wan Y, et al. Alcohol consumption and dementia risk: a dose-response meta-analysis of prospective studies. Eur J Epidemiol. 2017;32:31–42.