ABSTRACT

Objective: The purpose of this study was to examine the mediating effect of cognitive function on the relationship between participation in physical activity and independence of instrumental activities of daily living (IADL). Methods: A retrospective cross-sectional design that analyzed the association between physical activities and IADL and the mediating effects of cognitive function. We retrieved 3,980 beneficiaries from the 6 million people eligible for the Korean health insurance and benefits, between 2002 and 2015. The study subjects were 60 years and older and have completed the physical activity questionnaire. We estimated the indirect effect of physical activity through cognitive function on the independence of IADL. Results: The average age of the beneficiaries was 81.6 years (SD = 5.5), and 72.74% were female. Among the three physical activities, the vigorous-intensity exercise showed the largest partial mediation effect of cognitive function on the independence of IADL (β = 0.07, 95% confidence interval; CI: 0.05, 0.09). However, the walking exercise showed the largest direct effect on the independence of IADL (β = 0.11, 95% CI: 0.09, 0.14). Conclusion: The study indicated that there was a considerable mediating effect of cognitive function on the relationship between physical activities and IADL. The study findings would help clinicians establish a complex occupational therapy program that utilizes both physical and cognitive therapeutic modalities for old adults.