Duration of depressive symptoms and mortality risk: The English Longitudinal Study of Ageing (ELSA)

BACKGROUND: The relationship between the duration of depressive symptoms and mortality remains poorly understood. AIMS: To examine whether the duration of depressive symptoms is associated with mortality risk. METHOD: Data (n= 9560) came from the English Longitudinal Study of Ageing (ELSA). We assessed depressive symptom duration as the sum of examinations with an eight-item Center for Epidemiologic Studies Depression Scale score of ⩾3; we ascertained mortality from linking our data to a national register. RESULTS: Relative to those participants who never reported symptoms, the age- and gender-adjusted hazard ratios for elevated depressive symptoms over 1, 2, 3 and 4 examinations were 1.41 (95% CI 1.15-1.74), 1.80 (95% CI 1.44-2.26), 1.97 (95% CI 1.57-2.47) and 2.48 (95% CI 1.90-3.23), respectively (Pfor trend <0.001). This graded association can be explained largely by differences in physical activity, cognitive function, functional impairments and physical illness. CONCLUSIONS: In this cohort of older adults, the duration of depressive symptoms was associated with mortality in a dose-response manner.