Long-term associations of PM1 versus PM2.5 and PM10 with asthma and asthma-related respiratory symptoms in the middle-aged and elderly population

Abstract

Background Few studies have compared the associations between long-term exposures to particulate matters (aerodynamic diameter ≤1, ≤2.5 and ≤10 µm: PM1, PM2.5 and PM10, 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 PM1, PM2.5 and PM10 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 PM1/PM2.5/PM10 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 PM1, PM2.5 and PM10 was associated with a greater odds (OR (95% CI)) of asthma (PM1: 1.22 (1.02–1.45); PM2.5: 1.24 (1.04–1.48); PM10: 1.30 (1.07–1.57)), wheeze (PM1: 1.27 (1.11–1.44); PM2.5: 1.30 (1.14–1.48); PM10: 1.34 (1.17–1.55)), persistent cough (PM1: 1.33 (1.06–1.66); PM2.5: 1.36 (1.09–1.71); PM10: 1.31 (1.02–1.68)) and dyspnoea (PM1: 2.10 (1.84–2.41); PM2.5: 2.17 (1.90–2.48); PM10: 2.29 (1.96–2.66)). Sensitivity analysis results were robust after excluding individuals with a family history of allergy. Associations of PM1, PM2.5 and PM10 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.