Sensitive windows in association between early-life exposure to ambient particulate matter and childhood asthma
- VernacularTitle:生命早期大气颗粒物暴露与儿童哮喘关联的敏感窗口期研究
- Author:
Quanlong REN
1
;
Hao CHEN
2
;
Yunquan ZHANG
3
;
Ling ZHANG
4
;
Chuansha WU
5
Author Information
- Publication Type:Selectedarticle
- Keywords: particulate matter; preschool children; asthma; sensitive window; sex-specific association
- From: Journal of Environmental and Occupational Medicine 2026;43(9):1077-1085
- CountryChina
- Language:Chinese
- Abstract: Background Childhood asthma has been associated with exposure to particulate matter (PM), and the magnitude of this association may differ by particle size. However, many previous epidemiological studies have generally used trimester-specific or annual average PM concentrations as exposure metrics, which may mask the effects of short-term high-concentration exposures. Furthermore, evidence remains limited regarding weekly sensitive windows of PM exposure during pregnancy and infancy, particularly with respect to sex-specific susceptibility. Objective To identify sensitive windows for the associations of PM exposure of different particle size during pregnancy and infancy with childhood asthma and to examine potential sex differences. Methods As part of the China, Children, Homes, Health (CCHH) study, a questionnaire-based survey was conducted from June 2019 to June 2020 to obtain data on asthma-related information from 28788 preschoolers from seven Chinese cities. A spatiotemporal extremely randomized trees (STET) model was employed to estimate exposure to submicron particulate matter (PM1), fine particulate matter (PM2.5), and inhalable particulate matter (PM10). Weekly sensitive exposure windows were assessed using distributed lag nonlinear models (DLNMs), followed by sex-stratified analyses. Restricted cubic spline (RCS) functions were further applied among boys and girls to evaluate the dose–response relationship between size-fractionated PM exposure during the week with the largest effect estimate and childhood asthma. Results The mean concentrations of PM1, PM2.5, and PM10 across the seven cities were (34.5±7.2), (62.3±10.4), and (103.5±21.9) μg·m−3, respectively, with significant between-city differences. Wuhan had the highest PM1 and PM2.5 concentrations, Urumqi had the highest PM10 concentration, and Shanghai generally exhibited lower concentrations across all particle size fractions. The sensitive windows for the associations of PM1, PM2.5, and PM10 exposure with childhood asthma started at postnatal weeks 15, 17, and 29, respectively, and persisted until week 52. The maximum effect estimates for all three particle sizes were observed at week 52 (PM1, OR=1.0358, 95%CI: 1.0135, 1.0587; PM2.5, OR=1.0191, 95%CI: 1.0087, 1.0296; and PM10, OR=1.0103, 95%CI: 1.0047, 1.0159). No sensitive window was identified during the prenatal period. In sex-stratified analyses, exposure to PM1, PM2.5, and PM10 during postnatal weeks 18–52, 22–52, and 24–52, respectively, was associated with increased odds of childhood asthma in boys, whereas no sensitive window was identified in girls. Exposure-response curves showed monotonically increasing asthma risks in boys when PM1, PM2.5, and PM10 concentrations exceeded 11.9, 22.3, and 41.7 μg·m−3, respectively; this pattern was not observed in girls. Conclusion Postnatal exposure to PM rather than prenatal exposure is associated with increased odds of childhood asthma, with distinct sensitive windows during infancy. Smaller particles, particularly PM1, show larger effect estimates, earlier onset, and longer duration of sensitive windows. Boys appear to be more susceptible to early-life PM exposure than girls, as reflected by strong associations and more distinct sensitive windows.
