Potential determinants of T helper 2 markers and their distribution in school-aged children

Background: There is growing data on T helper 2 (Th2) biomarker determinants in adult populations. However, the determinants and typical range of these biomarkers have not been well studied in general populations of children. Therefore, we assessed the determinants and typical range of three Th2 bio-markers, including blood eosinophils, FeNO, and serum total IgE in 9-11-year-old children in a pro-spective birth cohort.Methods: We examined the pre-and postnatal factors associated with Th2 biomarkers using multivar-iable logistic regression analysis (n = 428) and extended the results to the original cohort (n = 17,009) using inverse probability weighting. We also measured typical Th2 biomarker distribution in all exam-ined children and healthy participants without allergic diseases (n = 180).Results: At age 9-11, wheeze (odds ratio (OR) 7.63), rhinitis (OR 3.14), and eczema (OR 2.46) were significantly associated with increased blood eosinophils. All three allergic conditions were associated with FeNO and total serum IgE, but the ORs were smaller than those for blood eosinophils. Secondhand smoking was inversely associated with the blood eosinophils (OR, 0.38). Similar results were found in the original cohort. Male sex and prenatal factors (maternal smoking and parental history of allergies) were not independent predictors of high Th2 levels.Conclusions: In addition to wheezing and rhinitis, eczema and secondhand smoke exposure are inde-pendent factors for Th2 biomarker interpretation in children. Furthermore, the typical values and cutoff values of blood eosinophils in adults may not be applicable to children.(c) 2022 Japanese Society of Allergology. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).