Relationship between Physical Activity, Handgrip Strength, Depressive Symptoms, and Cognitive Impairment in Korean older adults

Abstract

AbstractBackgroundPhysical activity, muscle strength, depressive symptoms, and cognitive function are intertwined in later life. This study aimed to investigate the association physical activity (PA), relative handgrip strength (RHGS), depressive symptoms, and cognitive impairment in Korean older adults.MethodThis study consisting of 512 community‐dwelling Korean older adults (417 female, 95 male) aged 65 years and older (74.8±5.4 years) in S‐city, Gyeonggi‐do. PA and handgrip strength were assessed with the Global Physical Activity Questionnaire and using a dynamometer (GRIP‐D; Takei Ltd, Niigata, Japan). Depressive symptoms were evaluated using the Korean form of the Center for Epidemiologic Studies Depression (CES‐D) Scale. Cognitive impairment was assessed with the Mini‐Mental State Examination for Dementia Screening (MMSE‐DS) of Korean version. The PROCESS V3.4 macro for SPSS based on the bootstrap method was used to determine the mediating effects of PA and RHGS on the relationship between depressive symptoms and cognitive impairment.ResultMultiple logistic regression showed that insufficient PA was associated with high odds of a cognitive impairment ((OR = 2.972, 95%CI = 1.749‐5.052, p = .002) compared with sufficient PA (OR = 1). Weak RHGS (OR = 3.540, 95%CI = 2.156‐5.814, p<.001) was associated with high odds of the cognitive impairment compared with normal RHGS (OR = 1). Depressive symptoms (OR = 2.676, 95%CI = 1.594‐4.492, p<.001) were associated with higher odds of the cognitive impairment compared with normal depression status (OR = 1). Particularly, depressive symptoms were found to have both direct and indirect effects on cognitive impairment. As predicted, PA and RHGS partially mediated the relationship between depressive symptoms and cognitive impairment (PA: B = –0.017, 95%CI = –0.028 ‐ –0.009, p<.001; RHGS: B = –0.005, 95%CI = –0.007 ‐ –0.003, p<.001). In addition, serial mediation analysis indicates that the association between depressive symptoms and cognitive impairment was partially mediated by PA and RHGS in a sequential manner (B = –0.004, 95%CI = –0.006 ‐ –0.002, p<.001).ConclusionAccording to the results of the serial multiple mediation model, the elderly should be encouraged to continue their physical activity in daily life, which not only improves and maintaining muscular strength but also reduces the negative impact of depressive symptoms on cognitive impairment.