Depressive symptoms in middle age and the development of later-life functional limitations: the long-term effect of depressive symptoms.

OBJECTIVES To determine whether middle-aged persons with depressive symptoms are at higher risk for developing activity of daily living (ADL) and mobility limitations as they advance into older age than those without. DESIGN Prospective cohort study. SETTING The Health and Retirement Study (HRS), a nationally representative sample of people aged 50 to 61. PARTICIPANTS Seven thousand two hundred seven community living participants in the 1992 wave of the HRS. MEASUREMENTS Depressive symptoms were measured using the 11-item Center for Epidemiologic Studies Depression Scale (CES-D 11), with scores of 9 or more (out of 33) classified as significant depressive symptoms. Difficulty with five ADLs and basic mobility tasks (walking several blocks or up one flight of stairs) was measured every 2 years through 2006. The primary outcome was persistent difficulty with ADLs or mobility, defined as difficulty in two consecutive waves. RESULTS Eight hundred eighty-seven (12%) subjects scored 9 or higher on the CES-D 11 and were classified as having significant depressive symptoms. Over 12 years of follow-up, subjects with depressive symptoms were more likely to reach the primary outcome measure of persistent difficulty with mobility or difficulty with ADL function (45% vs 23%, Cox hazard ratio (HR)=2.33, 95% confidence interval (CI)=2.06-2.63). After adjusting for age, sex, measures of socioeconomic status, comorbid conditions, high body mass index, smoking, exercise, difficulty jogging 1 mile, and difficulty climbing several flights of stairs, the risk was attenuated but still statistically significant (Cox HR=1.44, 95% CI=1.25-1.66). CONCLUSION Depressive symptoms independently predict the development of persistent limitations in ADLs and mobility as middle-aged persons advance into later life. Middle-aged persons with depressive symptoms may be at greater risk for losing their functional independence as they age.