LOS ANGELES — Adhering to a healthy lifestyle reduces the risk of developing dementia, even in those at genetic risk of Alzheimer’s disease (AD), new research suggests.
Investigators found that individuals at high genetic risk who followed an unhealthy lifestyle were almost three times more likely to develop dementia within 8 years than those with a low genetic risk and a favorable lifestyle.
Fewer participants with high genetic risk who had a healthy lifestyle developed dementia than their counterparts with an unhealthy lifestyle.
This is the first study to comprehensively investigate whether a healthy lifestyle offsets genetic risk for dementia, study investigator Elzbieta Kuzma, PhD, research fellow in neuroepidemiology, University of Exeter Medical School, England, told Medscape Medical News.
“Although our study does not prove a causal relationship, the take-home message is very optimistic, as our results indicate that living a healthy lifestyle was associated with a reduced dementia risk regardless of genetic risk.”
The study sends “a very important public health message,” added Kuzma.
“It suggests that healthy lifestyle interventions may help to prevent or delay dementia, even in people with high genetic risk.”
The findings were presented here at the Alzheimer’s Association International Conference (AAIC) 2019. The study was also published online July 14 in the Journal of the American Medical Association.
Researchers used data from the UK Biobank study, a population-based cohort of more than 500,000 participants who attended one of 22 assessment centers across the United Kingdom between 2006 and 2010.
From this Biobank, researchers identified 196,383 individuals aged at least 60 years (mean age 64.1 years), 52.7% of them women, who had available genetic information and did not have dementia at baseline.
For each study subject, researchers calculated a polygenic risk score. They used previously published data from genome-wide association studies for AD in those with European ancestry, and included almost 250,000 individual genetic variants that they weighted according to association with AD and then standardized.
The variants included APOE but many others, too, said Kuzma. “It was a really comprehensive polygenic risk score.”
From this genetic information, they categorized subjects into low (lowest quintile), intermediate (quintiles 2 to 4), and high (highest quintile) genetic risk for developing dementia.
The research team also developed a healthy lifestyle index for each study subject. They used four well-established dementia risk factors — smoking status, physical activity, diet, and alcohol consumption.
Study subjects self-reported this information on a questionnaire at baseline.
Researchers categorized smoking status as current or not current smoker. They defined regular physical activity as at least 150 minutes of moderate activity per week or 75 minutes of vigorous activity per week — or an equivalent combination.