Physical inactivity and depressive symptoms in older adults: A cross-national analysis of cohort studies in high- and low-income countries.

OBJECTIVES: This study aims to investigate the association between physical activity (PA) and depressive symptoms among older adults in high-income countries (HICs) and low-and middle-income countries (LMICs).

METHODS: Data from 127,580 individuals aged 60 and above, spanning 32 countries from 2011 to 2020, were analyzed using five national cohort studies. PA levels were self-reported, and depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale (CES-D) or the European Depression Scale (EURO-D). Logistic regression, within a Generalized Estimating Equations (GEE) framework, adjusted for confounders using the Minimal Sufficient Adjustment Set (MSAS) identified via directed acyclic graph (DAG).

RESULTS: Prevalence of physical inactivity was: HRS 22.4 %, ELSA 19.8 %, SHARE 13.2 %, CHARLS 44.0 %, and MHAS 32.8 %. PA was significantly associated with depressive symptoms in HRS (OR = 1.49, 95 % CI 1.41-1.57, P < 0.001), ELSA (OR = 1.82, 95 % CI 1.68-1.98, P < 0.001), SHARE (OR = 1.73, 95 % CI 1.67-1.80, P < 0.001), and CHARLS (OR = 0.90, 95 % CI 0.84-0.97, P = 0.003). No significant association was found in MHAS (OR = 0.95, 95 % CI 0.89-1.01, P = 0.089).

CONCLUSIONS: Physical inactivity is widespread among older adults, particularly in LMICs. In HICs, PA is strongly linked to depressive symptoms, whereas the association is weaker in LMICs. These findings suggest that increasing PA may improve mental health in older populations in HICs. Future studies should explore the impact of different PA dimensions and consider socio-cultural and economic factors when developing interventions for older adults.