What you probably already know: Drinking any amount of alcohol may increase the risk of dementia, according to a huge new study from the universities of Oxford, Yale and Cambridge. While previous research has linked heavy drinking to increased dementia risks, the effects of moderate drinking were unclear — some studies even suggested small amounts of alcohol are actually good for the brain. But this new study rules out that possibility. “Genetic evidence offers no support for a protective effect,” says lead study author Dr. Anya Topiwala “In fact, it suggests the opposite. Even light or moderate drinking may increase the risk of dementia.”
Why? The researchers analyzed data from more than 559,000 people who participated in the UK Biobank and the US Million Veteran Program. In the follow-up period, 14,540 participants developed dementia. The observational part of the study — which looked at self-reported drinking data — seemed to support the idea that light drinkers (fewer than seven drinks a week) had a lower risk of dementia compared to non-drinkers (many of whom had stopped drinking because of illness) and heavy drinkers (40 or more drinks a week). Heavy drinkers and non-drinkers had a 41% higher risk of developing dementia compared to light drinkers, while the risk for those who were alcohol dependent jumped to 51%. But context is key: Those previous studies suggesting neuroprotective benefits from light drinking only captured a snapshot of a person’s drinking habits, focused on older people and didn’t differentiate between former drinkers and lifelong drinkers. For this new study, genetic analysis was the key to separating correlation from causation — and the results were striking. After examining 45 studies of dementia in 2.4 million people, the researchers found no protective effect from any amount of alcohol. Instead, they found a higher genetic risk for alcohol consumption was associated with a higher risk of dementia. This increased with the rate of drinking, with a 15% higher dementia risk for three drinks per week compared to just one drink per week across a person’s lifetime.
What it means: Drinking increases the odds of developing a slew of health problems, from various cancers to strokes to heart attacks. When it comes to brain health, there may be no safe drinking threshold for anyone. “Our findings do not only hold for those who have a particular genetic predisposition, but for anyone who chooses to drink, our study suggests that greater alcohol consumption leads to higher risk of dementia,” Dr. Stephen Burgess says. While the study didn’t draw any gender-based conclusions, it’s worth pointing out that women are more likely than men to develop dementia in general: The lifetime risk for Alzheimer’s at age 45 is one in five for women, compared to one in 10 for men. Meanwhile, women — particularly those over 30 — are drinking significantly more alcohol today than they did just a few decades ago, despite increased risks of breast cancer. Alcohol is hard on everyone, but mortality rates are rising faster among women than men, partly because women are biologically more likely to develop liver disease from excessive drinking.
What happens next: Alcohol is neurotoxic, and the concept of “everything is safe in moderation” simply doesn’t apply to booze. The study authors say their findings could help increase awareness about the impacts of drinking on brain health and shape preventative strategies and health guidelines. They suggest that if alcohol use disorder rates were slashed in half, dementia rates could drop by up to 16%. “Reducing alcohol consumption across the population could play a significant role in dementia prevention,” Topiwala says.
