Do depressive symptoms predict declines in physical performance in an elderly, biracial population?

Objective: We investigated whether depressive symptoms, assessed by the 10-item Center for Epidemiological Studies Depression Scale (CES-D), predicted change in physical function in elderly adults. Methods: Participants were from a biracial, population-based sample of adults aged 65 and older (N: 4069; 61% black; 61% female). Physical function was assessed as a summary performance measure of tandem stand, measured walk, and repeated chair stand (mean [standard deviation], 10.3 [3.5]; range, 0-15), commonly used measures of overall physical health in older adults. Generalized estimating equation models estimated physical function across 3 assessments over 5.4 years of follow up as a function of CES-D scores at baseline. Results: Adjusting for age, sex, race, and education, each 1-point higher CES-D score was associated with a 0.34-point lower absolute level of physical performance (p < .0001), but there was no evidence of a CES-D by time interaction (p = .84), indicating that depressive symptoms at baseline were not associated with greater physical performance decline over time. In secondary analyses, with CES-D scores modeled in 4 categories, overall physical performance showed a graded, inverse association across CES-D categories (p's < .0001). However, we observed no threshold effect for depressive symptoms in relation to change in physical performance. Compared with the referent group (CES-D = 0), the 2 middle CES-D categories (CES-D = I or 2-3) evidenced some decline in physical performance over time, but the highest CES-D group (CES-D :4) showed no significant physical decline over time (p = .89). Conclusion: We observed a strong cross-sectional association between depressive symptoms and overall physical performance. Physical function declined over time, yet depressive symptoms did not consistently contribute to greater decline over an average of 5.4 years of follow up among older adults. Findings highlight the importance of longitudinal models in understanding the relation between depressive symptomatology and physical health. Key words: depressive symptoms, physical function, white, black, health, longitudinal.