Interaction of household air pollution and healthy lifestyle on the risk of sarcopenia: China Health and Retirement Longitudinal Study.

Background: Exposure to air pollution and adherence to a healthy lifestyle have been identified to be related to sarcopenia. However, the interactive effects between these two factors remain insufficiently elucidated. The present study was designed to investigate the potential interaction exposure to air pollution with healthy lifestyle on the risk of developing sarcopenia.

Methods: In the retrospective cohort study, all data was extracted from China Health and Retirement Longitudinal Study. Household air pollution was assessed based on the utilization of solid fuels for cooking and heating. A lifestyle score was constructed comprising information on physical activity, smoking, drinking and sleeping time. Multivariate logistic regression model was used to assess the effects of household air pollution and healthy lifestyle score on sarcopenia, separately. We further explored the additive interaction between household air pollution and healthy lifestyle score to sarcopenia using the interaction table developed by T Anderson. Relative excess risk due to interaction (RERI), attributable proportion (AP), and synergy index (SI) were used to evaluate the additive interactive effect.

Results: 2,114 participants were included in this study. The result indicated that exposed to household air pollution [adjusted relative risk (RR) = 1.80, 95% confidence interval (CI): 1.15-2.94] and unhealthy lifestyle (adjusted RR = 1.46, 95%CI: 1.04-2.03) were both significantly associated with increased risk of sarcopenia. Furthermore, participants exposed to both household air pollution and an unhealthy lifestyle exhibited a significantly higher risk of sarcopenia relative to those without household air pollution exposure and maintaining a healthy lifestyle (adjusted RR = 2.44). But RERI, AP, and SI suggested that there is no statistically significant additive interaction between household air pollution exposure and healthy lifestyle factors in relation to sarcopenia risk.

Conclusion: Household air pollution in conjunction with an unhealthy lifestyle confers a significantly higher risk of sarcopenia compared to either factor in isolation, with no evidence of a significant additive interaction between these two risk factors.