Live healthier: reduce dementia risk?
The results of new retrospective, cohort study, suggest that, in older individuals with no baseline cognitive impairment, a healthy lifestyle may deter dementia, despite prevalence of genetic risk factors.
A retrospective, observational, cohort study has demonstrated that a healthy lifestyle can help offset dementia risk amongst older persons at high genetic risk for the development of dementia.
The study assessed 196,383 European individuals over the age of 60, who were dementia-free at the start of the 8-year study. Participants’ genetic data was attained from the UK Biobank.
Participants’ display of genotypes associated with Alzheimer’s disease or dementia were used to generate polygenic scores for individuals’ genetic dementia risks. The strength of the association between possession of each risky genetic variant and Alzheimer’s disease prevalence was considered when calculating these genetic risk scores for dementia.
Scores for participants’ lifestyles were calculated based on questionnaires that assessed their smoking habits, level of physical activity, diet and alcohol consumption.
Over the course of the study, 1769 of the 196,383 participants were diagnosed with dementia, as determined from hospital inpatient and death records.
An unhealthy lifestyle score, in combination with a high genetic risk score, was associated with a hazard ratio for dementia of 2.83 compared with individuals who had healthy lifestyles and low genetic risk scores.
Importantly, a healthy lifestyle was correlated with significantly reduced dementia risk, even in combination with a high genetic risk score. This suggests that individuals’ genetic risks and healthy lifestyles are independently linked to their risk of dementia.
Elżbieta Kuźma, joint lead study from the University of Exeter Medical School (Exeter, UK), commented: “This is the first study to analyze the extent to which you may offset your genetic risk of dementia by living a healthy lifestyle. Our findings are exciting as they show that we can take action to try to offset our genetic risk for dementia. Sticking to a healthy lifestyle was associated with a reduced risk of dementia, regardless of the genetic risk.”
David Llewellyn, joint lead study author from the University of Exeter Medical School and the Alan Turing Institute (London, UK), stated: “This research delivers a really important message that undermines a fatalistic view of dementia. Some people believe it's inevitable they'll develop dementia because of their genetics. However, it appears that you may be able to substantially reduce your dementia risk by living a healthy lifestyle.”
Lourida I, Hannon E, Littlejohns TJ et al. Association of Lifestyle and Genetic Risk With Incidence of Dementia. JAMA. doi: 10.1001/jama.2019.9879 (2019) (Epub ahead of print);