Long-term associations of PM₁versusPM2.5and PM₁₀with asthma and asthma-related respiratory symptoms in the middle-aged and elderly population

Background Few studies have compared the associations between long-term exposures to particulate matters (aerodynamic diameter ≤1, ≤2.5 and ≤10 µm: PM 1 , PM 2.5 and PM 10 , respectively) and asthma and asthma-related respiratory symptoms. The objective of the present study was to compare the strength of the aforementioned associations in middle-aged and elderly adults. Methods We calculated the mean 722-day personal exposure estimates of PM 1 , PM 2.5 and PM 10 at 1 km×1 km spatial resolution between 2013 and 2019 at individual levels from China High Air Pollutants (CHAP) datasets. Using logistic regression models, we presented the associations as odds ratios and 95% confidence intervals, for each interquartile range (IQR) increase in PM 1 /PM 2.5 /PM 10 concentration. Asthma denoted a self-reported history of physician-diagnosed asthma or wheezing in the preceding 12 months. Results We included 7371 participants in COPD surveillance from Guangdong, China. Each IQR increase in PM 1 , PM 2.5 and PM 10 was associated with a greater odds (OR (95% CI)) of asthma (PM 1 : 1.22 (1.02–1.45); PM 2.5 : 1.24 (1.04–1.48); PM 10 : 1.30 (1.07–1.57)), wheeze (PM 1 : 1.27 (1.11–1.44); PM 2.5 : 1.30 (1.14–1.48); PM 10 : 1.34 (1.17–1.55)), persistent cough (PM 1 : 1.33 (1.06–1.66); PM 2.5 : 1.36 (1.09–1.71); PM 10 : 1.31 (1.02–1.68)) and dyspnoea (PM 1 : 2.10 (1.84–2.41); PM 2.5 : 2.17 (1.90–2.48); PM 10 : 2.29 (1.96–2.66)). Sensitivity analysis results were robust after excluding individuals with a family history of allergy. Associations of PM 1 , PM 2.5 and PM 10 with asthma and asthma-related respiratory symptoms were slightly stronger in males. Conclusion Long-term exposure to PM is associated with increased risks of asthma and asthma-related respiratory symptoms.