Association of poor subjective sleep quality with risk for death by suicide during a 10-year period: a longitudinal, population-based study of late life

Abstract

Importance: Older adults have high rates of sleep disturbance, die by suicide at disproportionately higher rates compared with other age groups, and tend to visit their physician in the weeks preceding suicide death. To our knowledge, to date, no study has examined disturbed sleep as an independent risk factor for late-life suicide.

Objective: To examine the relative independent risk for suicide associated with poor subjective sleep quality in a population-based study of older adults during a 10-year observation period.

Design, setting, and participants: A longitudinal case-control cohort study of late-life suicide among a multisite, population-based community sample of older adults participating in the Established Populations for Epidemiologic Studies of the Elderly. Of 14 456 community older adults sampled, 400 control subjects were matched (on age, sex, and study site) to 20 suicide decedents.

Main outcomes and measures: Primary measures included the Sleep Quality Index, the Center for Epidemiologic Studies-Depression Scale, and vital statistics.

Results: Hierarchical logistic regressions revealed that poor sleep quality at baseline was significantly associated with increased risk for suicide (odds ratio [OR], 1.39; 95% CI, 1.14-1.69; P < .001) by 10 follow-up years. In addition, 2 sleep items were individually associated with elevated risk for suicide at 10-year follow-up: difficulty falling asleep (OR, 2.24; 95% CI, 1.27-3.93; P < .01) and nonrestorative sleep (OR, 2.17; 95% CI, 1.28-3.67; P < .01). Controlling for depressive symptoms, baseline self-reported sleep quality was associated with increased risk for death by suicide (OR, 1.30; 95% CI, 1.04-1.63; P < .05).

Conclusions and relevance: Our results indicate that poor subjective sleep quality is associated with increased risk for death by suicide 10 years later, even after adjustment for depressive symptoms. Disturbed sleep appears to confer considerable risk, independent of depressed mood, for the most severe suicidal behaviors and may warrant inclusion in suicide risk assessment frameworks to enhance detection of risk and intervention opportunity in late life.

Figure 1. Self-reported Sleep Quality at Baseline and Risk for Death by Suicide at 10 Follow-up Years

The mean Sleep Quality Index total scores are shown for cases (20 suicide decedents) compared with 400 age and sex–matched control subjects. Higher Sleep Quality Index total scores reflect poorer subjective sleep quality. Error bars represent standard errors. χ ² = 10.87 (odds ratio, 1.39; 95% CI, 1.14-1.69; P < .001).

Figure 2. Self-reported Sleep Quality at Baseline as a Predictor of Risk for Death by Suicide

The receiver operating characteristic curve for baseline Sleep Quality Index total scores distinguishes cases (20 suicide decedents) from 400 age and sex–matched control subjects. Higher Sleep Quality Index total scores reflect poorer subjective sleep quality.