Age Differences in the Etiology of the Relationship between Life Satisfaction and Self-Rated Health

Abstract

This study explores age differences in the genetic and environmental influences that may mediate the relationship between life satisfaction and self-rated health. The participants are from the Swedish Adoption/Twin Study of Aging (SATSA), which includes 99 pairs of identical twins reared apart, 166 pairs of identical twins reared together, 238 pairs of fraternal twins reared apart, and 221 pairs of fraternal twins reared together. A mailed questionnaire included four items inquiring about perceived health and the 13-item shortened version of the Life Satisfaction Index, which yielded a general principal component for life satisfaction. Important age differences were found in the etiology of individual differences for each scale and in the factors that mediate the relationship between the measures. In the group younger than 65 years, the correlation between life satisfaction and perceived health can be explained entirely by environmental influences. For the group aged 65 and older, both genetic and environmental effects contribute substantially to the relationship. These age differences may reflect age-related changes, cohort effects, or both.