Widowhood, physical inactivity, and frailty in Chinese elderly: A cross-sectional study highlighting interaction and intervention targets

Widowhood and physical inactivity (PA) are established risk factors for frailty in older adults, but their potential synergistic effect remains underexplored in China's aging population. This study investigated the independent and joint associations of widowhood and low physical activity level (PAL) with frailty among Chinese elderly. Using 2018 China Health and Retirement Longitudinal Study (CHARLS) data, 4969 adults aged ≥ 50 years were analyzed. Frailty was assessed via the FRAIL scale (scores ≥ 3). Widowhood status (widowed vs non-widowed) and PAL (low vs high) were primary exposures. Hierarchical multivariable logistic regression models adjusted for sociodemographic, health, and psychosocial covariates examined associations and interaction effects. Frailty prevalence was 27.7%. Widowhood independently increased frailty risk (adjusted odds ratio [AOR] = 1.84, 95% CI: 1.52-2.23, P < .001). Low PAL was associated with higher frailty risk (AOR = 2.10, 95% CI: 1.78-2.48, P < .001). Critically, a significant interaction between widowhood and low PAL was observed (β = 0.18, P < .001), indicating synergistic effects: widowed individuals with low PAL had substantially elevated frailty risk compared to those with neither risk (AOR = 3.92, 95% CI: 3.15-4.88). Widowhood and PA are independent and synergistic predictors of frailty in Chinese elderly. Targeted interventions should prioritize integrated strategies combining psychosocial support for the bereaved with structured moderate-to-vigorous PA promotion (≥23 MET-h/wk) to mitigate frailty in this high-risk group.