Lifestyle lowers dementia risk except for APOE4 homozygotes

A new study has clarified the significant but limited role of lifestyle interventions in preventing dementia, depending on an individual's genetic risk. The research, led by scientists at Kyushu University and RIKEN in Japan, found that while healthy habits can substantially reduce dementia risk for many people, they offer no measurable protection for those with the highest genetic susceptibility.

The study, published on May 21 in the journal Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring, analyzed data from 9,605 community-dwelling Japanese adults aged 65 and older. Researchers examined the interaction between a person's genetic profile, specifically the APOE ε4 gene variant—a primary genetic risk factor for Alzheimer's disease—and their modifiable risk factors. These factors include behaviors and conditions people can change, such as physical activity levels, blood pressure control, and smoking status.

The results showed dementia risk increased progressively with the number of APOE ε4 alleles a person carries. Individuals inheriting two copies of the allele, known as homozygotes, faced a more than tenfold higher risk of dementia compared to non-carriers....