Effect of exposure to fine particulate matter during pregnancy and infancy on paediatric allergic rhinitis.

BACKGROUND The effect of prenatal and postnatal exposure to fine particulate matter (PM2.5) on the development of allergic rhinitis (AR) is poorly understood. We further identified the vulnerable period for AR development to determine methods to decrease adverse effects. METHODS We used a large population-based birth cohort of 140 911 singleton live infants in Taichung, Taiwan with a highly temporal-resolution satellite-based hybrid model to evaluate the effects of prenatal and early postnatal exposure on the onset of AR. RESULTS Among 140 911 children, 47 276 (33.55%) were cases of incident AR. The mean age of the children with AR at initial diagnosis was 2.97±1.78 years. We identified a significant association of AR with an interquartile range (IQR 17.98 µg/m3) increase in PM2.5 from 30 gestational weeks to 52 weeks after birth. The exposure-response relationship revealed that AR had a significant positive association between PM2.5 of 26-76 µg/m3 (adjusted hazard ratios ranged from 1.00 to 1.05). CONCLUSION Our study provides evidence that both prenatal and postnatal exposures to PM2.5 are associated with later development of AR. The vulnerable time window may be within late gestation and the first year of life. Further study is required to confirm the vulnerable time period of PM2.5 on AR.