The effect of gender, age, and symptom severity in late-life depression on the risk of all-cause mortality: the Bambuí Cohort Study of Aging.

Background: Increased mortality risk and its moderators is an important, but still under recognized, negative outcome of late-life depression (LLD). Therefore, we aimed to evaluate whether LLD is a risk factor for all-cause mortality in a population-based study with over 10 years of follow-up, and addressed the moderating effect of gender and symptom severity on mortality risk.

Methods: This analysis used data from the Bambuí Cohort Study of Aging. The study population comprised 1.508 (86.5%) of all eligible 1.742 elderly residents. Depressive symptoms were annually evaluated by the GHQ-12, with scores of five or higher indicating clinically significant depression. From 1997 to 2007, 441 participants died during 10,648 person-years of follow-up. We estimated the hazard ratio for mortality risk by Cox regression analyses.

Results: Depressive symptoms were a risk factor for all-cause mortality after adjusting for confounding lifestyle and clinical factors (adjusted HR = 1.24 CI95% [1.00-1.55], P = .05). Mortality risk was significantly elevated in men (adjusted HR = 1.45 CI95% [1.01-2.07], P = 0.04), but not in women (adjusted HR = 1.13 CI95% [0.84-1.48], P = 0.15). We observed a significant interaction between gender and depressive symptoms on mortality risk ((HR = 1.72 CI95% [1.18-2.49], P = 0.004).

Conclusion: The present study provides evidence that LLD is a risk factor for all-cause mortality in the elderly, especially in men. The prevention and adequate treatment of LLD may help to reduce premature disability and death among elders with depressive symptoms.