Even if You Have a Gene Linked to Dementia Risk?
Researchers have identified variations in genes that predispose people to developing dementia. However, healthy lifestyle choices can decrease your risk of dementia. Could better lifestyle choices reduce your risk of dementia even if you have a gene that predisposes you to dementia? Researchers in the UK investigated this question using genetic and lifestyle data from a subset of UK Biobank participants age 60 years or older. The UK Biobank includes more than 500,000 participants of European ancestry. Healthy lifestyle choices included 1) not smoking, 2) adequate physical activity, 3) moderate alcohol consumption, and 4) a healthy diet.
Over a median follow-up of 8 years, participants with a high risk for dementia and who had a healthy lifestyle had a 32 percent lower risk of developing dementia compared to participants who had an unhealthy lifestyle. Thus, a healthy lifestyle predicted a substantially lower risk of dementia even for those with a high genetic risk for dementia. The risk of dementia increases as age increases. This study may have underestimated the old-age benefits of healthy living, because the participants at the end of follow-up averaged only 72 years of age. You can’t alter your genetic heritage, but you can make better lifestyle choices that may reduce your risk of dementia in your later years.
Cognitive reserve refers to the ability of a well-stimulated brain to withstand, in part, the adverse effects of brain pathologies. Certain lifestyle factors appear to enhance cognitive reserve. Would people who engage in cognitive-reserve enhancing activities over their life course be less likely to develop dementia late in life? If so, would this positive effect occur in persons who are genetically predisposed to dementia? Researchers at the Karolinska Institute in Sweden used data from the Kungsholmen Project to find out. Participants for the present study included 602 persons at least 75 years of age in 1987 and who were dementia-free both at baseline and three years later.
Ten cognitive-reserve enhancing factors spanned 1) early life (educational attainment, number of siblings, socio-economic status); 2) mid-life (job demands, decision latitude, work complexity with data, work complexity with people); and 3) late life (physical activity, mental activity, social activity). Genetic predisposition for dementia arose from having the apolipoprotein E gene. Participants in the highest quartile of cognitive-enhancing activities had significantly lower risk of developing dementia over the average 8-year follow-up period, compared to participants in the lowest quartile. The reductions in dementia risk were 55, 54, and 56 percent, respectively, for early, mid, and late life. The presence of the apolipoprotein E gene did not negate the beneficial effect of cognitive-reserve enhancing factors. What a powerful good-news story! If you adopt healthy lifestyle choices over the course of your life, you may reduce your risk of dementia. But it’s never too late. Even late-life cognitive enhancing factors predicted reduced risk of dementia.