Prenatal, Postnatal Exposure to Fine Particulate Matter Linked to Allergic Rhinitis

Development of allergic rhinitis in children is significantly associated with prenatal and postnatal exposure to fine particulate matter (PM_2.5), according to study results published in Thorax. In addition, the results suggest that there may be a vulnerable time window later in gestation to the first year of life.

While several epidemiologic studies have confirmed the link between PM_2.5 and allergic respiratory diseases, few studies have analyzed PM_2.5 in association with lung development. Furthermore, there has been recent debate about the effects of PM_2.5 on induced allergic rhinitis.

To address these disparities, a team of investigators in Taiwan conducted a large population-based birth cohort study using a temporal-resolution satellite-based hybrid model to determine the effects of prenatal and postnatal exposure to PM_2.5, and any associated vulnerable periods, for the development and onset of allergic rhinitis.

Of the 140,911 children surveyed, there were 47,276 incident cases of allergic rhinitis. The mean age at initial diagnosis among patients was 2.97±1.78 years, and the mean weekly concentrations of PM_2.5 during pregnancy and the first year after birth were 34.26±13.01 and 33.56±4.67mg/m³, respectively.

Diagnosis was more likely in patients who were boys (hazard ratio [HR], 1.29), those who had maternal atopy (HR, 1.73), had a preterm birth status (HR, 1.10), had a higher socioeconomic status (HR, 1.21), maternal heart disease (HR, 1.62), maternal hypertension (HR, 1.32), and maternal preeclampsia (HR, 1.18).

Study results also suggested that an increased interquartile range in the concentration of PM_2.5 (17.98 mg/m³) from 30 gestational weeks to 52 weeks after birth was significantly associated with allergic rhinitis. The highest HR was recorded at 46 weeks after birth, and there was a significant positive exposure-response relationship between allergic rhinitis and PM_2.5 ranging from 26 to 76 mg/m³ (HR ranged from 1.00-1.05 per 1 mg/m³ increase).

“Although many epidemiological and animal studies have suggested that PM_2.5 is a risk factor in the development of [allergic rhinitis], this is the first birth cohort study to identify the vulnerable window from gestation to early childhood,” the authors wrote.

Some limitations to the study included the potential for exposure misclassification among participants who might have changed residential location and the inability to evaluate allergic rhinitis sensitization status.

“Further studies are required to confirm the association between prenatal and postnatal exposures to [PM_2.5] and [allergic rhinitis] incidence and to verify the vulnerable time window,” concluded the investigators.

Reference

Lin Y-T, Shin H, Jung C-R, et al. Effect of exposure to fine particulate matter during pregnancy and infancy on paediatric allergic rhinitis. Thorax. Published online March 11, 2021. doi:10.1136/thoraxjnl-2020-215025