Interactive Associations of Atmospheric Humidity and Air Pollutants with Self-reported Chronic Lung Disease Risk: Evidence from a Nationwide Population-Based Study in China.
BACKGROUND Chronic lung diseases (CLD) pose a substantial public health burden. Although air pollution is a recognized risk factor, atmospheric humidity may influence respiratory health. Evidence evaluating multidimensional humidity indicators together with air pollution in relation to chronic lung disease in China remains limited. METHODS Data from 16,204 adults aged ≥45 years from the 2011, 2013, and 2015 waves of the China Health and Retirement Longitudinal Study (CHARLS) were analyzed. Annual exposures to six air pollutants (CO, NO2, O3, PM2.5, PM10, SO2) and six humidity indicators (RH, AVP, VPD, DPT, MR, SH) were estimated at 1-km resolution. Multivariable logistic regression and restricted cubic spline models were applied. Stratified and sensitivity analyses were conducted. RESULTS Higher concentrations of CO, NO2, O3, PM2.5, and SO2 were linearly associated with increased self-reported CLD risk, while PM10 showed an approximate U-shaped relationship. Each interquartile-range increase in air pollutant concentrations was associated with an 18-45% higher odds of self-reported CLD. AVP, VPD, DPT, MR, and SH were positively associated with self-reported CLD risk, whereas RH exhibited an inverted U-shaped pattern. Weighted quantile sum analyses showed significant positive associations for both air pollution and humidity mixtures. A significant interaction between RH and sex was observed. Sensitivity analyses across different lag structures confirmed that air pollutants and atmospheric humidity were consistently associated with self-reported CLD risk. CONCLUSIONS Long-term exposure to ambient air pollution and multidimensional humidity indicators was independently associated with higher self-reported CLD risk, highlighting the importance of considering meteorological factors in disease prevention.