Background: The present study was to investigate the association of physical activity (PA), relative-handgrip strength (RHGS), depressive symptoms, and cognitive impairment in Korean older adults.
Methods: This study included 512 community-dwelling Korean older adults (417 female, 95 male) aged ≥65 years (74.8 ± 5.4 years). PA and HGS were assessed using an accelerometer and dynamometer, respectively. Depressive symptoms were evaluated by the Korean form of the Center for Epidemiologic Studies Depression (CES-D) Scale. Cognitive impairment was assessed through the Mini-Mental State Examination for Dementia Screening (MMSE-DS).
Results: Multiple logistic regression analysis revealed that depressive symptoms (OR = 2.676, 95%CI: 1.594–4.492, p < 0.001) showed a significant association with increased odds of cognitive impairment compared with normal depression status (OR = 1). Depressive symptoms had both direct and indirect effects on cognitive impairment. Both PA and RHGS partially mediated the relationship between depressive symptoms and cognitive impairment (PA: effect [B] = –0.017, 95%CI: –0.028 to –0.009, p < 0.001; RHGS: B = –0.005, 95%CI: –0.007 to –0.003, p < 0.001). Serial mediation analysis further indicated that the association between depressive symptoms and cognitive impairment was sequentially mediated by PA and RHGS (B = –0.004, 95%CI: –0.006 to –0.002, p < 0.001).
Conclusion: Promoting PA among older adults may be crucial, as this helps improve and maintain muscular strength and mitigates the negative impact of depressive symptoms on cognitive impairment.