EXPRESS: Air pollution increases cardiometabolic diseases in China: A nationwide longitudinal cohort study

Objective: To investigate the associations between long-term exposure to multiple ambient air pollutants (PM1, PM2.5, PM10, O3 and NO2) and the incidence of cardiometabolic multimorbidity (CMM) in middle-aged and older Chinese adults, and to identify potential effect modifiers. Design: Nationwide longitudinal cohort study. Setting: The China Health and Retirement Longitudinal Study (CHARLS), covering 28 provinces in China. Participants: A total of 8,725 participants aged 45 years and older from the CHARLS 2011 baseline, free of pre-existing CMM, defined as having two or more of the following four conditions: hypertension, diabetes, cardiovascular disease, and stroke, with complete follow-up data through 2020. Participants with only one of these conditions at baseline were retained. Primary and secondary outcome measures: The primary outcome was incident CMM. Secondary outcomes included pollutant-specific hazard ratios and effect modification by education level and sleep duration. Sensitivity analyses using multiple imputation were performed to assess the robustness of the associations for all five pollutants. Results: Long-term exposure to PM1, PM2.5, PM10, O3 and NO2 was significantly associated with an increased risk of incident CMM. Stronger associations were observed among participants with lower educational attainment and shorter sleep duration. Conclusions: Long-term exposure to ambient air pollutants is associated with a higher risk of CMM in the Chinese middle-aged and older population. These findings highlight the importance of air quality improvement and targeted public health strategies for socioeconomically disadvantaged and sleep-deprived subgroups.