Patterns of Association between Depressive Symptoms and Chronic Medical Morbidities in Older Adults

OBJECTIVES To investigate the association between depressive symptoms and several medical morbidities, and their combination, in a large older population. DESIGN Cross-sectional study of baseline data from the ASPirin in Reducing Events in the Elderly (ASPREE) trial. SETTING Multicentric study conducted in Australia and the United States. PARTICIPANTS A total of 19,110 older adults (mean age = 75 years [standard deviation = +/- 4.5]). MEASUREMENTS Depressive symptoms were measured using the Center for Epidemiological Studies Depression (CES-D 10) scale. Medical morbidities were defined according to condition-specific methods. Logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) to test associations before and after accounting for possible confounders. RESULTS Depressive symptoms were significantly associated with obesity (OR = 1.19; 95% CI = 1.07-1.32), diabetes (OR = 1.22; 95% CI = 1.05-1.42), gastroesophageal reflux disease (GERD) (OR = 1.41; 95% CI = 1.28-1.57), metabolic syndrome (OR = 1.16; 95% CI = 1.03-1.29), osteoarthritis (OR = 1.41; 95% CI = 1.27-1.57), respiratory conditions (OR = 1.25; 95% CI = 1.10-1.42), history of cancer (OR = 1.19; 95% CI = 1.05-1.34), Parkinson's disease (OR = 2.56; 95% CI = 1.83-3.56), polypharmacy (OR = 1.60; 95% CI = 1.44-1.79), and multimorbidity (OR = 1.29; 95% CI = 1.12-1.49). No significant association was observed between depressive symptoms and hypertension, chronic kidney disease, dyslipidemia, and gout (P > .05). A significant dose-response relationship was evident between the number of medical comorbidities and the prevalence of depression (OR = 1.18; 95% CI = 1.13-1.22). CONCLUSION Late-life depressive symptoms are significantly associated with several medical morbidities, and there appears to be a cumulative effect of the number of somatic diseases on the prevalence of depression. These findings augment the evidence for a complex relationship between mental and physical health in an otherwise healthy older population and might guide clinicians toward early recognition of high-risk individuals.