Alcohol consumption and risk of dementia: a systematic review and meta-analysis

To examine the relationship between alcohol intake and the risk of developing dementia, we conducted a comprehensive search of PubMed, Embase, Cochrane Library and Web of Science databases for relevant studies up to July 22, 2024. The quality of the original studies was appraised utilising the Newcastle-Ottawa Scale (NOS). The link between alcohol intake and the risk of dementia was presented using relative risks (RRs) and their corresponding 95% confidence intervals (CIs). Subgroup analyses were implemented based on the level of alcohol consumption, geographic region and age. All statistical analyses were executed utilising Stata 15.0. The meta-analysis unveiled no significant link between alcohol exposure and the risk of developing dementia, including all-cause dementia (ACD) (RR = 1.03, 95% CI: 0.84-1.27), Alzheimer disease (AD) (RR = 0.97, 95% CI: 0.86-1.08), vascular dementia (VD) (RR = 1.09, 95% CI: 0.95-1.26) and other dementia (RR = 0.62, 95% CI: 0.33-1.15). In the subgroup analysis by drinking levels, light to moderate alcohol intake was linked to a decreased risk of ACD and AD (RR = 0.88, 95% CI: 0.81-0.96; RR = 0.88, 95% CI: 0.79-0.97, respectively). Nonetheless, heavy alcohol consumption significantly increased the risk of developing all types of dementia (ACD, RR = 1.18, 95% CI: 1.02-1.36; AD, RR = 1.29, 95% CI: 1.21-1.36; VD, RR = 1.25, 95% CI: 1.11-1.40). Further subgroup analyses indicated that light to moderate drinking's protective effect was stronger in Europe and among individuals aged 60 to 69 years. Light to moderate drinking may protect against dementia, while heavy drinking or alcohol use disorders raises dementia risk.