The effects of comorbidities on the trajectory of depressive symptoms among older adults in Taiwan

Objective: This study aimed to identify depressive symptoms among older Taiwanese adults and to explore the relationships between different comorbidities and depressive symptoms. Methods: The data used herein were obtained from four waves of a longitudinal nationwide survey of the older Taiwanese population conducted from 1996 to 2007. Two-level hierarchical linear modeling was employed to identify the trajectory of depressive symptoms predicted by comorbidities when controlling for time-constant and time-varying covariates. Results: The time slope had an increasing tendency of depressive symptoms across time. The older adults with cardiovascular disease (CVD), gastrointestinal disease, chronic respiratory disease (CRD), and the combination of two of these three diseases had a higher effect on the intercept of depressive symptoms. Only the older adults with CRD combined with CVD or with GI disease had a significant negative effect on the slope of depressive symptoms over time. Participants with higher emotional-social support had lower depressive symptoms, and the effect of this support could reduce depressive symptoms even more over time. Conclusions: Different patterns of comorbidities might have an additive or modifying effect on depressive symptoms. Emotional social support had a buffering or moderating effect on the prevention of depressive symptoms. This information is helpful for further studies that would address the relationships between different comorbidities and depressive symptoms.