Insomnia symptoms predict both future hypertension and depression

The prevalence of hypertension and depression is high in older populations. Moreover, their comorbidity may significantly increase morbidity and mortality. However, the risk factors contributing to both health conditions are not well understood. Older individuals are prone to insomnia; thus we hypothesized that having more insomnia symptoms increases risk for incident hypertension and depression over time. The sample consisted of a longitudinal population-based study of community-dwelling older individuals, from the 2008-2016 waves of the Health and Retirement Study, sampled across the United States. A total of 18,123 subjects, aged 50+, were stratified into three age groups, ages 50-60, 61-74, and 75 and older years. Subjects were excluded for reporting baseline hypertension or depression at the first wave 2008. Center for Epidemiologic Studies-Depression (CES-D) score >= 4 was the cutoff for elevated depressive symptomatology. Subjective insomnia symptoms were evaluated. Cox proportional hazards regression revealed that SBP (1.02[1.01, 1.02]) and more insomnia symptoms (1.11 [1.01, 1.21]) were significant predictors of hypertension for all age groups. For depression, only insomnia symptoms were significant predictors (9.91 [6.37, 15.41]). Kaplan-Meier curves revealed that 9.2% of the overall cohort had both hypertension and depression within 8 years and more insomnia symptoms predicted greater incidences of both conditions (p-values < 0.001). In this older prospective cohort, insomnia symptoms are consistent predictors of future hypertension and depression in all age groups, who were not hypertensive and depressed at baseline. Insomnia may contribute to the etiology and comorbidity of hypertension and depression in older individuals.