LAUSR

OBJECTIVE Previous studies on the relationship of bisphenol-A (BPA) with fractional exhaled nitric oxide (FeNO) had conflicting results, suggesting that other factors may modulate this relationship. Thus, we investigated the modulating effect of vitamin D on the relationship of BPA with FeNO in children. PATIENTS AND METHODS This study recruited 432 children (10 to 12 years old) from the general pediatric population of Korea between June and July 2017. We conducted measurements of urinary BPA, serum vitamin D, specific serum IgE, FeNO, and data from impulse oscillometry (reactance area [AX], airway resistance at 5 Hz [Rrs5] and 20 Hz [Rrs10], and the difference of Rrs5 and Rrs20 [Rrs5-20]). RESULTS Serum vitamin D (adjusted β =- 0.014, p=0.002) and urinary BPA (β = 0.006, p<0.001) level was significantly associated with FeNO. Urinary BPA level was significantly associated with FeNO in children with low vitamin D levels (≤23 ng/mL; αβ = 0.006, p < 0.001), but not in children with high vitamin D levels (>23 ng/mL). The interaction of vitamin D and BPA had a significant effect on FeNO (pint = 0.005). There was no relationship with the airway lung function (Rrs5, AX, and Rrs5-20) to serum vitamin D and urinary BPA level. Vitamin D ameliorated the BPA-mediated increase of FeNO in children. CONCLUSIONS These results suggest that children with low vitamin D levels may be more susceptible to airway inflammation due to BPA.