The study examined health records of over 559,000 participants from the Million Veteran Program in the US and the UK Biobank databases. Participants aged between 56 and 72 were followed for 4 to 12 years, during which more than 14,000 were diagnosed with dementia.
Observational analyses showed that people consuming 40 or more drinks per week and alcohol-dependent individuals had a 41% to 51% increased risk. However, genetic analyses found no "U-shaped protective effect"; instead, dementia risk increased linearly with each additional drink consumed.
Confirmed by genetic data
Using a genetic method called Mendelian randomization, the study found that genetic variants associated with alcohol consumption increased dementia risk. Just 1–3 extra drinks per week raised the risk by 15%, while doubling the genetic predisposition for alcohol dependence was linked to a 16% higher risk.
Why were previous studies misleading?
Scientists explained that earlier studies suggesting alcohol's protective effect were likely biased because people reduce alcohol intake in early dementia stages, making low consumption appear beneficial due to reverse causation.
Experts' warning
Researchers highlighted that even low levels of alcohol are not "safe" and reducing alcohol consumption could be a key strategy to prevent dementia.
In conclusion, the new study strongly disproves the idea that moderate drinking is beneficial for the brain and shows that any amount of alcohol increases dementia risk.
