Data reported at the Alzheimer’s Association International Conference in Los Angeles, July 14-18, 2019 and published today in JAMA, suggest lifestyle modifications may reduce risk of developing Alzheimer’s disease (AD) even in the presence of higher genetic risk for AD.
Data from 196,383 adults of European ancestry age 60 or more were analyzed for presence of dementia, genetic risk factors for dementia, and healthy lifestyle factors. Dementia incidence was 60% higher among those with high vs low genetic risk (hazard ratio [HR], 1.60; 95% confidence interval [CI], 1.25 to 2.05).
Participants with a high genetic risk and an unfavorable lifestyle had more than a threefold higher risk of dementia compared with those with low genetic risk and favorable lifestyle (HR, 3.44; 95% CI, 2.28 to 5.18). Genetic factors did not significantly modify the relationship between the healthy lifestyle index and dementia risk. The risk of all-cause dementia was more than halved among participants with a high genetic risk following a favorable lifestyle compared with an unfavorable lifestyle (HR, 0.46; 95% CI, 0.32 to 0.68).
Cases were identified as having high, intermediate, and low genetic risk for dementia using polygenic risk scores. The healthy lifestyle index used included no current smoking, regular physical activity, healthy diet and moderate alcohol consumption with favorable (3 or 4 health behaviors), intermediate (2 health behaviors) and unfavorable (0 or 1 health behaviors) categories. Hospital inpatient and death records were used to identify all-cause dementia, and the statistical analysis controlled for age, sex, education, socioeconomic status and relationship with other individuals included in the study.
These data suggest that genetic and lifestyle factors independently have strong associations with dementia risk.
“This research is exciting in that it shows there are actionable things we can do to try to counteract genetic risk for dementia,” said Elzbieta Kuźma, PhD, research fellow, University of Exeter Medical School. “In our study, adherence to a healthy lifestyle was associated with a reduced risk of dementia regardless of the genetic risk.”