A healthy lifestyle might reduce the risk for dementia, even in people with a high genetic risk, new research suggests.
British researchers writing in JAMA studied 196,383 people over 60 and free of dementia at the start of the study. They assigned each a “polygenic risk score,” based on their number of common genetic variants associated with dementia, and a “healthy lifestyle score,” based on smoking, physical activity, diet and alcohol consumption.
Over an average eight-year follow-up, people with the highest genetic risk were at a 91 percent higher risk for dementia compared with those with the lowest. Those with the worst lifestyle scores were at a 34 percent higher risk compared to those with the best. But people with both the worst lifestyle scores and the highest genetic risk were at nearly triple the risk of those with the best scores in both domains.
There was no correlation between genetic risk score and lifestyle score, which suggests that lifestyle is an independent risk factor for dementia risk.
The study was observational, so it cannot determine whether an unhealthy lifestyle actually causes dementia, only that there was an association between the two.
“There are no guarantees,” said the senior author, David J. Llewellyn, an associate professor at the University of Exeter Medical School. “Some people who did all the right things still developed dementia. But our findings suggest that it may be possible to reduce your risk by about a third by living a healthy lifestyle, regardless of your genetic risk.”