Longitudinal associations between cardiovascular-kidney-metabolic syndrome and sensory impairments in Chinese middle-aged and older adults: a weighted marginal structural model analysis

BACKGROUND: Sensory impairments significantly contribute to functional decline in aging populations, yet their relationship with the newly defined cardiovascular-kidney-metabolic (CKM) syndrome remains poorly understood. This study examined the longitudinal associations between CKM syndrome stages and incident sensory impairments among middle-aged and older Chinese adults. METHODS: Data were derived from 12,815 participants (aged ≥ 45 years) in the China Health and Retirement Longitudinal Study (2011–2018), with a median follow-up of 6.5 years. CKM stages (0–4) were defined according to the 2023 American Heart Association framework. Incident hearing impairment (HI), vision impairment (VI), and dual sensory impairment (DSI) were assessed using validated self-reports. To address confounding, weighted marginal structural models (MSM) were employed using inverse probability of treatment weighting (IPTW). Sensitivity was further evaluated using E-value calculations and alternative reference groups. RESULTS: After IPTW adjustment, advanced CKM syndrome (Stage 4) was significantly associated with increased odds of incident HI (OR = 1.36, 95% CI: 1.05–1.74) and DSI (OR = 1.50, 95% CI: 1.04–2.15) compared with Stage 0 (optimal health). Although the association for VI was not statistically significant (OR = 1.29, 95% CI: 0.93–1.77), significant dose-response trends were observed across the CKM continuum for HI, VI (both Ptrend = 0.005), and DSI (Ptrend < 0.001). Subgroup analyses revealed more pronounced associations among older adults, rural residents, and those with lower educational attainment. Sensitivity analyses and moderately high E-values supported the robustness of these findings against potential residual confounding. CONCLUSIONS: Advanced CKM syndrome is longitudinally associated with higher odds of sensory impairments, particularly DSI, in a graded manner. These findings suggest that incorporating sensory health into CKM management frameworks may be crucial for mitigating the burden of functional decline in aging populations.