Lifestyle risk and delaying factors.

Research findings suggest that dementia risk is lower in individuals with more extensive education, greater engagement in mentally stimulating leisure activities during adulthood, and higher occupational complexity. Other recent findings support the importance of early-life risk factors, such as socioeconomic conditions, early-life development, and exposure to infection, in explaining individual differences in dementia risk. Life-style variables have been conceptualized as delaying factors, postponing onset of dementia and thereby reducing total population burden of dementia. Using a sample of Swedish twins from the HARMONY study, we found that education significantly affects dementia onset, that is, occurrence and timing of dementia symptoms. In the HARMONY data, we also showed that differences in education are reflected in differences in leisure activities and occupation, suggesting that differences in cognitive engagement begin early and persist over the life course. Such findings point to the importance of taking a life-course perspective to designing interventions to delay or to prevent dementia.