July 19, 2019
Maintaining a healthy lifestyle is associated with a lower risk of dementia in older adults, despite genetic risk, according to the results of a recent study.
While it is known that certain genetic factors can increase the risk of dementia, whether these factors can be offset by lifestyle is currently unknown.
Recently, researchers from the University of Exeter Medical School in Exeter, United Kingdom, conducted a retrospective cohort study of 196,383 individuals aged at least 60 years and without cognitive impairment at baseline. They used a polygenic risk score for dementia with low, intermediate, and high-risk categories along with a weighted healthy lifestyle score. Factors in the lifestyle score included smoking status, physical activity, healthy diet, and alcohol consumption. These were categorized as favorable, intermediate, or unfavorable.
Overall, 68.1% of the participants followed a favorable lifestyle, 23.6% followed an intermediate lifestyle, and 8.2% followed an unfavorable lifestyle. Of the participants, 20% had high polygenic risk scores, 60% had intermediate risk scores, and 20% had low risk scores.
Among those with high risk scores, 1.23% developed dementia compared with 0.63% of those with low risk scores (adjusted hazard ratio 1.91). Among those with high risk scores who followed an unfavorable lifestyle, 1.78% developed dementia compared with 0.56% of those with low risk and favorable lifestyle (hazard ratio 2.83). No significant interaction between lifestyle and genetic risk was observed.
Among those with high risk, 1.13% of those with favorable lifestyle developed dementia compared with 1.78% of those with unfavorable lifestyle (hazard ratio 0.68).
“Among older adults without cognitive impairment or dementia, both an unfavorable lifestyle and high genetic risk were significantly associated with higher risk of dementia. A favorable lifestyle was associated with a lower dementia risk among participants with a high genetic risk.”
Lourida I, Hannon E, Littlejohns TJ, et al. Association of lifestyle and genetic risk with incidence of dementia [published online July 14, 2019]. JAMA. doi:10.1001/jama.2019.9879.