Obstructive sleep apnea and risk for late-life depression

BACKGROUND: Obstructive sleep apnea (USA) is a sleep-related breathing disorder characterized by repetitive pharyngeal collapse. Because of the association between OSA, ischemia, and late-life depression, we hypothesized that older patients with USA would have a higher prevalence of depression relative to their younger counterparts. METHODS: We retrospectively reviewed charts of patients evaluated at the Sleep Disorders Center (SDC) at University of Iowa Hospitals and Clinics. A total of 617 patients age seen at SDC for diagnostic and therapeutic sleep studies were identified. Patients with a chart diagnosis of depressive disorder or treatment with antidepressants were identified as having a depressive disorder. Patients with an Apnea/Hypopnea Index were identified as having OSA. RESULTS: No evidence of an escalating prevalence of depression with age was found in patients with USA relative to those without the disorder. Prevalence of depression was similar in the USA and the nonapnea groups (40.9% vs 40.3%, respectively; chi(2) = 0.02; df = 1; P = .89). Individuals with USA had a significantly higher body mass index and greater number of chart diagnoses of hypertension, diabetes mellitus, and coronary artery disease compared with the nonapnea group. CONCLUSIONS: The prevalence of depression among individuals with USA does not appear to be moderated by age. Similarly high rates of depression were observed across the population of individuals referred for sleep studies, whether or not they were diagnosed with USA.