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

Summary

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 (P for 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.