New Study Shows Even Light Alcohol Use Increases Dementia Risk

A new study published in BMJ Evidence-Based Medicine shows that any level of alcohol consumption can increase the risk of dementia. Researchers also found that tripling weekly alcohol consumption—whether from one to three drinks per week or three to nine—was associated with a 15% increased risk of developing dementia.

In the study, researchers analyzed data from more than 550,000 adults between the ages of 56-72 years at baseline and genetic information from an additional 2.4 million participants of multiple genome-wide association studies. The study found that a higher genetic risk for alcohol use disorder was also associated with an increased risk of dementia.

“For a long time, we thought that the healthiest way to approach drinking and brain health was to take about a drink a day,” said Dr. Joel Gelernter, professor of psychiatry, genetics, and neuroscience at Yale University School of Medicine and senior author of the study. “I think people should be aware that even a small amount of alcohol intake may have negative cognitive effects down the line.”

The findings contradict prior observational research that suggested light to moderate drinking had the lowest dementia risk and that drinking might be “protective” against cognitive decline, when compared to nondrinkers. Instead, the researchers determined that earlier studies were likely influenced by two main issues: people in early stages of dementia often drink less, and non-drinkers may have previously been heavy drinkers who quit because of health issues.

Alcohol may reduce the brain’s reserve capacity, making it more vulnerable to damage from other causes. Researchers found that alcohol disrupts both gray and white matter in the brain, reducing brain volume, impairing the regeneration of myelin (the insulation that enables neurons to communicate), and increasing iron accumulation, which has been linked to neurodegenerative diseases such as Alzheimer’s and Parkinson’s. In addition, the study estimates that reducing the prevalence of alcohol use disorder could prevent up to 16% of dementia cases.

Dr. Anya Topiwala, a senior clinical researcher at the University of Oxford, added that reducing alcohol intake, even without complete cessation, can benefit brain health.

Key Findings

• Any level of drinking—light, moderate, or heavy—raises the risk of dementia.

• Every threefold increase in alcohol consumption was linked to a 15% higher lifetime risk of dementia.

• Prior research suggesting moderate drinking could be protective was likely influenced by misleading classifications of self-reported drinking habits, particularly among former drinkers.

• Alcohol’s impact includes reduced gray matter, impaired white matter recovery, and increased brain iron — all associated with neurodegeneration.

• Reducing the prevalence of alcohol use disorder could prevent up to 16% of dementia cases.

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The Article

Topiwala, A., Levey, D. F., Zhou, H., Deak, J. D., Adhikari, K., Ebmeier, K. P., Bell, S., Burgess, S., Nichols, T. E., Gaziano, M., Stein, M., & Gelernter, J. (2025). Alcohol use and risk of dementia in diverse populations: Evidence from cohort, case–control and Mendelian randomisation approaches. BMJ evidence-based medicine, bmjebm-2025-113913. Advance online publication. https://doi.org/10.1136/bmjebm-2025-113913