The risk of developing atopic dermatitis due to these combined effects is especially prevalent in infant boys with high maternal anxiety.
A new investigation from Korea into the prenatal effects of exposure to prenatal particulate matter with an aerodynamic diameter of less than 2.5 μm (PM2.5) found that exposure during gestational weeks 5-8 was linked to an increased probability of atopic dermatitis in infancy. This was especially true in boys with higher maternal anxiety.
The investigation, led by Soo-Jong Hong,MD, PhD, Department of Pediatrics, University of Ulsan College of Medicine, Korea, addressed the increasing prevalence of atopic dermatitis worldwide.
Previous studies suggested that PM2.5, which ranged from fossil fuel combustion, power plants, tobacco smoke, burning candles, and more were considered especially harmful to human health, and these exposures combined with maternal anxiety have been suggested as potential causes of the atopic disease.
Several studies had detailed the interactive effect of particulate matter exposure and prenatal stress on asthma in children, yet the critical exposure periods for the interactive effect of prenatal PM2.5 exposure and maternal stress had not been examined in relation to infant atopic dermatitis.
Hong and colleagues investigated these combined effects during pregnancy on the risk of atopic dermatitis in infancy, which included the different effects according to infant gender.
The investigators initiated the study by enrolling 802 children from the Cohort for Childhood Origin of Asthma and allergic diseases (COCOA), a prospective birth cohort that identified various environmental factors for childhood allergic diseases.
Parental reports of a physician diagnosis of atopic dermatitis at the 6 and 12 months follow-up visits were used to determine atopic disease in individual children.
Exposure to outdoor PM2.5 was determined using land-use regression (LUR) models, and ambient concentrations of PM2.5 were measured by the Korean Ministry of Environment at 37 fixed monitoring stations in Seoul.
Hong and investigators measured maternal anxiety through self-reported questionnaites at 36 weeks of pregnancy based on the State-Trait Anxiety Inventory-Trait subscale (STAI-T).
Finally, associations between matter exposure during each trimester of pregnancy and atopic dermatitis at 1 year of age were evaluated with a logican regression model, with prenatal periods being by first (weeks 1-13), second (14-27), and third (weeks 28-40) trimesters.
A total of 107 (13.%) infants were diagnosed with atopic dermatitis at year 1, with significantly more diagnosis being recorded in boys. Additionally, family history of allergic diseases was higher in infants with atopic dermatitis than those without.
Investigators noted that the association between PM2.5 during the first trimester was significant, and that second and third trimesters of pregnancy were not associated with atopic dermatitis in infants.
As speculated, higher prenatal maternal anxiety and male gender were associated with the atopic disease in the first year. Among boys exposure to higher maternal anxiety during pregnancy, investigators reported that festational weeks 5-8 were the critical perioid of PM2.5 exposure.
Though some misclassifications of PM2.5 exposure were possible with the system, and adjustments were not made for other ambient air pollution, Hong and colleagues were confident in their findings and suggested that infantile atopic dermatitis could possibly be avoided.
“Avoidance of exposure to PM2.5 and maternal anxiety during the prenatal period, especially in the first trimester, may prevent the development of infantile AD,” the team wrote.
The study, “Prenatal PM2.5 affects atopic dermatitis depending on maternal anxiety and gender: COCOA study,” was published online in Clinical and Transitional Allergy.