Prenatal particulate matter affects new asthma via airway hyperresponsiveness in schoolchildren.

Abstract

The most relevant time of PM10 exposure to affect airway hyperresponsiveness (AHR) and new development of asthma in school-aged children is unclear. The aims of this study were to investigate the most critical time of PM10 exposure to affect AHR and new diagnosis of asthma from AHR in school-aged children. Elementary schoolchildren (n=3570) have been enrolled in a nationwide prospective 4-year follow-up survey in Korea from 2005 to 2006. Individual annual PM10 exposure was estimated by using an ordinary kriging method from the prenatal period to 7years of age. AHR at 7years was defined by a methacholine PC20 ≤8mg/mL. PM10 exposure during pregnancy and at 1year of age showed significant effects on AHR (aOR: 1.694, 95% CI: 1.298-2.209; and aOR: 1.750, 95% CI: 1.343-2.282, respectively). PM10 exposure during pregnancy was associated with the risk of a new diagnosis of asthma (aOR: 2.056, 95% CI: 1.240-3.409), with the highest risk in children with AHR at age 7 (aOR: 6.080, 95% CI: 2.150-17.195). PM10 exposure in the second trimester was associated with the highest risk of a new diagnosis of asthma in children with AHR at age 7 (aOR: 4.136, 95% CI: 1.657-10.326). Prenatal PM10 exposure in the second trimester is associated with an increased risk of a new diagnosis of asthma in school-aged children with AHR at 7years. This study suggests that PM10 exposure during a specific trimester in utero may affect the onset of childhood asthma via AHR.