2019 Volume 40 Issue 4 Pages 351-362
In this study, change in depressive symptoms and its associations with physical health in old age were examined. Coordinated analysis was conducted using data from Studies 1 and 2, which included four measurement occasions in nine years, starting from 1987, and three in four years from 2007, respectively. Variables which were conceptually equivalent across studies were selected and similar statistical models were applied. To examine how depressive symptoms change and whether they are associated with between-person differences and within-person variability in physical health (impairment in activities of daily living (ADLs) and number of diseases), multilevel models were estimated separately for each study. Age, gender, education, and marital status were included as covariates. Results of the two longitudinal studies revealed that depressive symptoms typically increased over time. Across all subjects, participants who reported higher impairment in ADLs and number of diseases exhibited more depressive symptoms. Among persons aged approximately 70 years and older, when participants reported higher impairment in ADLs than usual, they exhibited more depressive symptoms. These results suggest that depressive symptoms increase in old age and covary with impairment in ADLs across time in a single individual.
