A major new study has found that any amount of alcohol consumption could increase the risk of developing dementia, challenging the long-held belief that light drinking may protect the brain. Researchers from the University of Oxford, Yale University, and the University of Cambridge analysed data from more than 559,000 people in the UK Biobank and the US Million Veteran Programme, during which 14,540 participants developed dementia.
The observational data showed that heavy drinkers (40 or more drinks per week) and non-drinkers had a 41% higher risk of dementia compared with light drinkers (fewer than seven drinks per week). For those with alcohol dependency, the risk rose to 51%. However, genetic analysis using genome-wide association studies of 2.4 million people found that a higher genetic risk for alcohol consumption was consistently associated with a higher risk of dementia, undermining the idea that low-level drinking is protective.
Researchers note that previous observational studies may have been skewed by the “sick quitter” effect, where former drinkers who stopped due to illness are grouped with lifelong non-drinkers. A 2016 analysis found that when former drinkers were excluded, the apparent protective effect of light drinking largely disappeared.
Dr Anya Topiwala, senior clinical researcher at Oxford Population Health, said: “Genetic evidence offers no support for a protective effect, in fact, it suggests the opposite. 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 of Yale added: “There was a time when medical knowledge seemed to support that light drinking would be beneficial to brain health, and this work adds to the evidence that this is not correct.”
Dr Stephen Burgess from Cambridge emphasised that the findings apply to everyone: “Greater alcohol consumption leads to higher risk of dementia.” Alzheimer’s Research UK said the study adds to the evidence linking alcohol to dementia risk but stressed more research is needed. According to the Alzheimer’s Society, nearly 982,000 people in the UK currently live with dementia, a figure projected to reach 1.4 million by 2040.
