Impact of living environmental quality on sarcopenia in middle-aged and older adults: evidence from cross-sectional and cohort analyses

BACKGROUND: Sarcopenia is a common geriatric syndrome closely associated with adverse outcomes such as falls, disability, and mortality. However, the comprehensive impact of living environmental quality on sarcopenia remains inadequately evaluated. This study aimed to examine the association between living environmental quality and sarcopenia risk. METHODS: This study utilized data from the China Health and Retirement Longitudinal Study (CHARLS) between 2011 and 2015, including 12,883 participants for cross-sectional analyses and 6,248 participants for cohort analyses. A composite living environmental quality score (range 0-6) was constructed based on five core indicators: outdoor PM2.5 exposure, household cooking and heating fuels, drinking water sources, building type, and indoor temperature. Scores were categorized into low-risk (0-1), medium-risk (2-3), and high-risk (4-6) groups. Multivariable logistic regression and Cox proportional hazards models were applied to assess associations between living environmental quality and prevalent as well as incident sarcopenia. The relative contribution of individual environmental factors and subgroup differences were further explored. RESULTS: In cross-sectional analyses, participants in the high-risk group had a significantly higher odds of sarcopenia compared with the low-risk group (OR = 1.65, 95%CI: 1.36-2.01). Cohort analyses demonstrated that high-risk individuals also had an increased risk of incident sarcopenia (HR = 1.29, 95%CI: 1.04-1.61). Dose-response analyses indicated a significant linear increase in sarcopenia prevalence and incidence with higher environmental risk levels (P for trend <0.001). The analysis of relative contribution of environmental factors revealed that water source (36.1%) had the most significant impact in cross-sectional analysis, while building type (62.0%) demonstrated the highest contribution in longitudinal analysis. Subgroup analyses revealed significant effect modification by age (P for interaction = 0.037), with stronger associations observed among individuals younger than 60 years. CONCLUSIONS: Poor living environmental quality is independently associated with sarcopenia in a dose-response manner, with clean fuels, drinking water infrastructure, and housing structure emerging as actionable targets.