No safe amount of alcohol tied to dementia risk, study finds

A large international study found that any level of alcohol consumption was associated with a higher risk of developing dementia over four years, with the risk strongest among heavy drinkers. People consuming 40 or more drinks per week faced a 41% higher risk of dementia than light drinkers, defined as fewer than seven drinks weekly. Those who were alcohol-dependent had about a 51% increased risk. The researchers also noted that non-drinkers were not protected against dementia in their analyses. The study, conducted by teams at the University of Oxford, Yale University, and the University of Cambridge, followed 559,559 British and American adults, with 14,540 cases of dementia diagnosed during follow-up. It also incorporated a genetic analysis using genome-wide association study data from about 2.4 million people, examining three measures of alcohol exposure: self-reported weekly drinking, risky or problematic drinking, and alcohol dependence. No protective effect of low-level drinking was found; instead, dementia risk rose with higher levels of genetically predicted alcohol consumption.

In addition to the epidemiological findings, researchers noted that individuals who would go on to develop dementia tended to reduce their alcohol intake in the years before diagnosis. That pattern could reflect early cognitive decline limiting drinking rather than a protective biological effect of abstinence. Dr Anya Topiwala, a consultant psychiatrist and senior clinical researcher at the University of Oxford, noted that the results challenge the longstanding belief that light drinking could benefit brain health. “Our findings challenge the common belief that low levels of alcohol are beneficial for brain health,” she said. “Genetic evidence offers no support for a protective effect; even light or moderate drinking may increase the risk of dementia, indicating that reducing alcohol consumption across the population could play a significant role in dementia prevention.”

Dr Joel Gelernter, a Yale professor and study co-author, said the findings have clinical implications, adding that there was a time when medical knowledge seemed to support that light drinking would be beneficial to brain health. “This work adds to the evidence that this is not correct,” he said.

The study’s size and the combination of observational and genetic analyses were designed to address inconsistencies in prior work, but researchers caution that the research has limitations. Independent experts who reviewed the study stressed that self-reported alcohol use can be unreliable, particularly if memory problems are present in early dementia. They also noted that the genetic markers used to predict alcohol intake and dementia are not perfect, and the study does not prove causation.

Professor Tara Spires-Jones, director of the Centre for Discovery Brain Sciences at the University of Edinburgh, said the authors rightly acknowledge important caveats. “Self-reported alcohol use may not be accurate, particularly if people have memory problems in early stages of dementia, and the genetic markers used as predictors of both alcohol intake and dementia are not perfect,” she said. “Neither part of the study can conclusively prove that alcohol use directly causes dementia. But this adds to a large amount of similar data showing associations between alcohol intake and increased dementia risk, and fundamental neuroscience work has shown that alcohol is directly toxic to neurons in the brain.” Dr Leah Mursaleen, head of clinical research at Alzheimer’s Research UK, echoed the call for caution while emphasizing the need for more work to understand the impact of alcohol on brain health and how interventions might reduce risk.

Beyond the study’s findings, the discussion comes amid broad public health context. Recent polls indicate the average Briton consumes roughly 18 units of alcohol weekly, roughly equivalent to six pints of beer or six large glasses of wine. Health authorities in the United Kingdom recommend limiting intake to no more than 14 units per week, and U.S. guidelines advise women to limit to seven drinks per week and men to 14. The World Health Organization estimates that alcohol kills about three million people globally each year. The Oxford-Yale-Cambridge study arrives as researchers continue to pursue cleaner answers about how lifestyle factors influence dementia risk and whether reductions in drinking could translate into meaningful population-level prevention.

The dementia landscape is shaped by multiple factors. A landmark study published last year argued that nearly half of all Alzheimer’s cases could be prevented by addressing 14 lifestyle and health factors from childhood, with high cholesterol and vision loss among newly identified risks. Those findings sit alongside longstanding knowledge that genetics, smoking, hypertension and obesity influence dementia risk. In the meantime, health authorities emphasize proven brain-healthy practices, such as regular physical activity, a balanced diet, and management of cardiovascular risk factors. With no disease-modifying treatments currently available on the NHS for dementia, experts say population-level strategies to reduce risk could play an important role in slowing the tide of the condition.