The relationship between depressive symptoms and instrumental activities of daily living function among older adults in China and associations in age, sex, and outdoor activity engagement

Background: Although associations of depressive symptoms (DS) and instrumental activities of daily living (IADL) function in older Chinese adults, whether demographic characteristics and outdoor activity engagement modify any such associations has not been well documented. This study aimed to explore the association of DS with IADL function and investigate whether age, sex, and outdoor activity modify the association. Methods: This population-based cross-sectional study derived data from the 2017-2018 Chinese Longitudinal Healthy Longevity Survey (2017-2018 CLHLS). DS was measured using the 10-item Center for Epidemiological Studies Depression Scale (CESD-10). IADL function was assessed using eight items, including (1) visiting neighbors, (2) shopping, (3) cooking, (4) washing clothes, (5) walking one kilometer, (6) carrying five-kilogram weight, (7) crouching and standing three times, and (8) taking public transportation. Multivariate linear regression models were used to calculate β-coefficients and 95% CI to examine the association of DS with IADL function. Modification of the associations by age (65-79 years and ≥80 years), sex (male and female), and outdoor activity engagement (yes and no) were performed using stratified analyses and interaction tests. Results: Of the 12261 participants (59.91% aged 80 and older adults, 53.45% were females), 26.65% had been reported to DS. There was a significant association between DS and a higher risk of IADL disability (adjusted β=0.81, 95% CI=0.71, 0.92) than those without DS. Compared with quintile 1 of DS, participants who experienced quintile 5 of DS had an increased risk of IADL disability (adjusted β=1.19, 95% CI=1.06, 1.33). The demographic of age and sex, and outdoor activity engagement were shown to significantly modify the associations of DS with IADL function ( P for interaction<0.05). Conclusions: In this cross-sectional study in China, exposure to DS was at a higher risk of IADL disability. This association was modified by age, sex, and outdoor activity engagement. These findings indicate a need to prevent DS and a need for an intervention strategy for mental health to reduce the potential risk of IADL disability. Moreover, emphasizing personalized interventions that target individuals with DS exposure may minimize the burden of IADL disability in later life.