Genetic and environmental transactions linking cognitive ability, physical fitness, and education in late life.

Cognitive ability and physical fitness are important to the ability to live independently in late life. Both are also related to level of attained education, with better educated older adults tending to display better cognitive ability and better late-life physical health. Chronic illnesses that affect both physical and cognitive function, lifetime cognitive ability that facilitates healthy lifestyle choices, and general biological aging processes have been offered as 3 explanations for the late-life physical-cognitive correlation. Education is generally assumed to provide a protective environment. The authors used a sample of 1,053 twin pairs aged 70 and over and gene-environment moderation models to explore 5 hypotheses that could help to disentangle the genetic and environmental transactions involving physical and cognitive functions and education. Results provide some support for all 3 explanations for the physical-cognitive correlation and indicate the ways in which better education may support better function and lack of education may undermine it.