Sleep disturbances and risk of depression in older men

Introduction: Self-reported sleep disturbances are associated with an increased risk of depression in younger and older adults, but associations between objective assessments of sleep/wake disturbances via wrist actigraphy and risk of depression are unknown. Methods: Depressive symptoms (Geriatric Depression Scale [GDS]), self-reported (questionnaires), and objective (actigraphy) sleep parameters were measured at baseline in 2,510 nondepressed men 67 y or older. Depressive symptoms were reassessed an average of 3.4 ± 0.5 y later. Results: Of the 2,510 men without evidence of depression at baseline, 116 (4.6%) were depressed (GDS ≥ 6) at the follow-up examination. After adjusting for multiple potential confounders, including baseline depressive symptoms (GDS 0-5), there was evidence of an association between poor self-reported sleep quality and higher odds of being depressed at follow-up (multivariable odds ratio [MOR] = 1.53, 95% confidence interval (CI) 1.00-2.33). In age- and site-adjusted models, objectively measured reduced sleep efficiency (odds ratio [OR] = 1.88, 95% CI 1.13-3.13), prolonged sleep latency (OR = 1.77, 95% CI 1.04-3.00), greater nighttime wakefulness (OR = 1.48, 95% CI 1.01-2.18) and multiple long-wake episodes (OR = 1.69, 95% CI 1.15-2.47) were associated with increased odds of depression at follow-up, but these associations were attenuated and no longer significant after further adjustment for number of depressive symptoms at baseline. Self-reported excessive daytime sleepiness and objectively measured total sleep time were not associated with depression status at follow-up. Excluding baseline antidepressant users from the analyses did not alter the results. Conclusions: Among nondepressed older men, poor self-reported sleep quality was associated with increased odds of depression several years later. Associations between objectively measured sleep disturbances (e.g., reduced sleep efficiency, prolonged sleep latency, greater nighttime wakefulness, and greater long-wake episodes) and depression several years later were largely explained by a greater burden of depressive symptoms at baseline.