Air pollution exposure and multimorbidity patterns: evidence from a national cohort study in China

Multimorbidity prevalence in China has been rising annually and has emerged as a major health challenge. While air pollution contributes to individual Noncommunicable diseases (NCDs), its impact on distinct multimorbidity patterns remains unclear.

This prospective cohort study analyzed 36,144 participants from the China Family Panel Studies (2010-2022) without baseline multimorbidity. Among 6,839 individuals (18.9%) who developed multimorbidity during median 8-year follow-up, latent class analysis identified distinct disease patterns. Fine-Gray subdistribution hazard models assessed associations between eleven air pollutants (PM2.5, PM10, O3, NO2, SO2, CO, and five PM2.5 components) and pattern-specific multimorbidity.

Four multimorbidity patterns emerged: Musculoskeletal-Dominant (3.4%), Cardiopulmonary (3.4%), Cardiovascular-Metabolic (9.5%), and Digestive-Dominant (2.6%). In single-pollutant models, PM10 showed consistent adverse effects (sHR 1.12-1.48), while cold-season O3 demonstrated protective associations (sHR 0.66-0.78). After multi-pollutant adjustment, PM10 remained the strongest risk factor across all patterns (sHR 1.71-2.47). Both cold- and warm-season O3 maintained protective associations (sHR 0.43-0.82). PM2.5 retained significance only for Cardiovascular-Metabolic pattern (sHR 1.13, 95% CI: 1.05-1.21). Dose-response analyses revealed non-linear relationships with threshold effects.

Air pollutants demonstrate heterogeneous associations with multimorbidity patterns, with PM10 as a universal risk factor. These findings highlight the need for pattern-specific approaches in environmental health research and air quality policy development.