Depression and chronic medical illnesses in Asian older adults: the role of subjective health and functional status

OBJECTIVE: Depression in elderly is reportedly associated with a number of specific chronic illnesses. Whether each of these co-morbid associations results uniquely from disease-specific psychobiological responses or is mediated by non-specific factors like subjective health and functional status is unclear. METHOD: Analysis of data of 2,611 community-dwelling Chinese aged 55 and older, including depressive symptoms defined by Geriatric Depression Scale score >or= 5 and self-reports of specific chronic illnesses. RESULTS: The prevalence of depressive symptoms was 13.3%, lower in those without chronic illness (7.5%), and higher in those with illnesses (13.2-24.2%). Crude Odds Ratios (OR) were significantly elevated for hypertension, eye disorders, diabetes, arthritis, ischemic heart disease, asthma/COPD, stroke, osteoporosis, heart failure, thyroid problem, and gastric problem. In multivariable analyses, only asthma/COPD OR:2.85, 95% Confidence Intervals (CI): 1.36, 5.98, gastric problem (OR:2.64, 95% CI: 1.11, 6.29), arthritis (OR:1.87, 95% CI: 1.02, 3.42) and heart failure (OR:2.11, 95% CI: 0.98, 4.58) remained independently associated with depressive symptoms, after adjusting for comorbidities, subjective health and functional status, cognitive functioning, smoking, alcohol, psychosocial and demographic variables. CONCLUSION: Most comorbid associations of depressive symptoms with specific chronic illnesses are explained by accompanying poor self-reported health and functional status, but some illnesses probably have a direct psychobiological basis.