FRIDAY, Sept. 26, 2025 (HealthDay News) -- Alcohol use is associated with increased dementia risk, according to a study published online Sept. 23 in BMJ Evidence-Based Medicine.Anya Topiwala, D.Phil., from the University of Oxford in the United Kingdom, and colleagues examined the association between alcohol consumption and dementia in two large-scale population-based cohorts: the U.S. Million Veteran Program and the U.K. Biobank. The observational analysis included 559,559 adults aged 56 to 72 years at baseline who were followed for a mean of four and 12 years in the U.S. and U.K. cohorts, respectively. Genetic analyses included data from multiple large genome-wide association studies consortia with 2.4 million participants.The researchers found that 14,540 participants developed dementia during follow-up and 48,034 died. In observational analyses, there were U-shaped associations between alcohol and dementia risk, with higher risk among nondrinkers, heavy drinkers (>40 drinks per week; hazard ratio, 1.41), and those with alcohol use disorder (hazard ratio, 1.51) versus light drinkers. A monotonic increase in dementia risk was seen with greater alcohol consumption in a Mendelian randomization genetic analysis, with a 15 percent increase in dementia risk with a one-standard deviation increase in log-transformed drinks per week (inverse-variance weighted [IVW] odds ratio, 1.15). Increased dementia risk was also seen in association with a twofold increase in alcohol use disorder prevalence (IVW odds ratio, 1.16). Individuals who developed dementia experienced a decline in alcohol intake over time, suggesting reverse causation."Our findings highlight the importance of considering reverse causation and residual confounding in studies of alcohol and dementia, and they suggest that reducing alcohol consumption may be an important strategy for dementia prevention," the authors write.Two authors disclosed ties to the biopharmaceutical industry, and two authors disclosed ties to the publishing industry.Abstract/Full Text.Sign up for our weekly HealthDay newsletter