Particulate matter exposure during pregnancy increases risk of childhood asthma: modified by gender and NRF2 genotype.

Background: Exposure to particulate matter (PM) has been known to develop asthma in children and the oxidative stress-related mechanisms are suggested. For the development of asthma, not only the exposure dose but also the critical window and the risk modifying factors should be evaluated.

Objective: We investigated whether prenatal exposure to PM10 increases the risk of childhood asthma and evaluated the modifying factors, such as gender and reactive oxidative stress-related gene.

Methods: A general population-based birth cohort, the Panel Study of Korean Children (PSKC), including 1572 mother-baby dyads was analyzed. Children were defined to have asthma at age 7 when a parent reported physician-diagnosed asthma. Exposure to PM10 during pregnancy was estimated by land-use regression models based on national monitoring system. TaqMan method was used for genotyping nuclear factor, erythroid 2-related factor, NRF2 (rs6726395). A logistic Bayesian distributed lag interaction model (BDLIM) was used to evaluate the associations between prenatal PM10 exposure and childhood asthma by gender and NRF2.

Results: Exposure to PM10 during pregnancy was associated with the development of asthma (aOR 1.03, 95% CI 1.001.06). Stratifying by gender and NRF2 genotype, exposure to PM10 during 26-28 weeks gestation increased the risk of childhood asthma, especially in boys with NRF2 GG genotype.

Conclusions: A critical window for PM10 exposure on the development of childhood asthma was during 26-28 weeks of gestation, and this was modified by gender and NRF2 genotype.