The Role of Muscular Strength on the Relationship between Number of Chronic Diseases and Depressive Symptom in Older Adults

Abstract

PURPOSE: The aim of this study was to investigate whether muscular strength modulates the relationship between the number of chronic diseases (NCD) and depression in older adults of Korean descent.METHODS: Data from the Living Profiles of Older People Survey including 10,097 older adults of Korean descent aged ≥65 years were used. Depressive symptoms were defined as a score of ≥8 on the self-administered Korean version of the Geriatric Depression Scale. Muscular strength was assessed through a self-reported questionnaire. Chronic diseases comprising the NCD were defined as physician-diagnosed long-term conditions.RESULTS: Depressive symptoms were more prevalent as the NCD increased in both male (odds ratio [OR]=2.650; 95% confidence interval [CI]: 2.214-3.172, <i>p</i><.001) and female (OR=2.261; 95%CI: 1.880-2.720, <i>p</i><.001) patients. Similarly, depressive symptoms increased as muscular strength decreased in both male (OR=2.323, 95%CI: 1.757-3.073, <i>p</i><.001) and female (OR=2.280, 95%CI: 1.886-2.775, <i>p</i><.001) patients, even after adjustment for age, body mass index (BMI), smoking education, and marriage. Moderation analysis showed that the effects of the NCD on depressive symptoms was modulated by muscular strength (β=0.557, 95%CI=0.222-0.891, <i>p</i>=.001), even after adjustments for all the covariates.CONCLUSIONS: The findings of this study suggest that muscular strength plays a beneficial role in the NCD and depressive symptoms in older adults of Korean descent.