Alcohol consumption and risk of Alzheimer's disease: A dose-response meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational studies
PubMed 35171516 · doi:10.1111/ggi.14357
What was done
Authors conducted a systematic review and dose-response meta-analysis searching PubMed and Web of Science through September 1, 2019, examining the association between alcohol consumption and Alzheimer's disease (AD) risk. They calculated pooled relative risks (RR) with 95% confidence intervals, performed subgroup analyses across alcohol type, ethnicity, study design, and sex, and modeled non-linear dose-response curves.
What was found
Across 13 included studies, alcohol drinkers had a lower risk of AD compared with non-drinkers (RR 0.68, 95% CI 0.53–0.87; I² = 87.9%, P < 0.001). Wine consumption was specifically associated with reduced risk (RR 0.71, 95% CI 0.51–0.96). Stratification by ethnicity, sex, or study design yielded no statistically significant associations. In the dose-response analysis (6 studies), the overall association was non-linear but non-significant. However, sex-stratified dose modeling showed excess AD risk in men starting from 14.8 drinks per week (overall P = 0.023; non-linearity P = 0.025), whereas intake under 16.9 drinks per week in women showed a significant non-linear association with reduced AD risk (overall P = 0.002; non-linearity P = 0.019).
Why it matters
This study highlights potential sex-specific thresholds in alcohol's relationship with AD, suggesting protective associations at moderate levels in women and elevated risk beyond ~15 drinks weekly in men.
Limits
The analysis is constrained by high statistical heterogeneity (I² = 87.9%) and reliance on observational studies vulnerable to residual confounding, misclassification of intake, and 'sick quitter' bias in non-drinker reference groups. Only 6 of the 13 studies provided adequate data for dose-response modeling.
Cited by
- contradicts The World Alzheimer Report 2022 concluded that a protective effect against Alzheimer's disease exists only for red wine up to four glasses per day, but not for other alcohol types.