A Danish population-based twin study on general health in the elderly

Objectives: To study the relative influence of genetic and environmental fa ctors on self-rated health and hospitalization patterns in the elderly. Met hods: A survey among all 3,099 Danish twins ages 75 years and older identif ied in the Danish Twin Registry. An interview was conducted with 77% of the twins. The number of hospitalizations in the previous 18 years was obtaine d through register linkage, thereby obtaining health information on 96% of the study population, including all nonresponders. Results: Structural equa tion modeling suggested that approximately a quarter of the variation in th e liability to self-reported health and the number of hospitalizations coul d be attributed to genetic factors. The remaining variation was most likely due to nonfamilial environment. Analyses of the hospitalization patterns o f proxy responders and nonresponders suggest that the estimates of the gene tic influence on health outcomes in the study are conservative. Discussion: The present study indicates that variation in general health among the eld erly is partly explained by genetic factors.