Alcohol consumption and risk of Alzheimer's disease: A dose–response meta-analysis

Aim: This study aimed to investigate the association between alcohol consumption and the risk of Alzheimer's disease (AD). Methods: PubMed and Web of Science databases were systematically searched as of 1 September 2019. Relative risk and 95% CI were used to evaluate the association between alcohol consumption and AD risk. Subgroup analyses based on the type of alcohol, ethnicity, study design and sex were carried out. An alcohol dose–response meta-analysis was carried out. Results: A total of 13 studies were included in the quantitative synthesis, and six were used in the dose–response meta-analysis. Compared with non-drinkers, individuals who drank had a lower risk of AD (relative risk 0.68, 95% CI 0.53–0.87; I2 = 87.9%, P < 0.001). In subgroup analyses, drinking wine was found to reduce the occurrence of AD (relative risk 0.71, 95% CI 0.51–0.96). When stratified by ethnicity, sex and study design, no association was seen between AD risk and alcohol use. There was an overall non-linear, but not significant, association between alcohol intake dose and AD risk. A significant non-linear association was observed between excess AD risk and alcohol intake dose in men (overall P = 0.023; P for non-linearity = 0.025) starting from 14.8 drinks per week. Women's alcohol intake dose <16.9 drinks per week showed a significant non-linear association with decreased AD risk (overall P = 0.002; P for non-linearity = 0.019). Conclusions: Drinking alcohol could reduce the risk of AD. Alcohol dose had a non-linear, but non-significant, relationship with the development of AD. The amount of alcohol consumption showed significant sex-specific effects on AD. Geriatr Gerontol Int 2022; ••: ••–••.