Abnormal iron status is independently associated with reduced oscillometric lung function in schoolchildren

Background Associations between anemia and allergic diseases have been reported, but the relationship of iron deficiency with airway dysfunction in children remains unclear. We aimed to investigate the relationship between abnormal iron parameters and lung function in schoolchildren. Methods Four hundred and forty-five children (10-12 years-old) from 11 elementary schools in were enrolled. The relationships of different iron parameters (hemoglobin, serum iron, transferrin saturation, and serum ferritin) with lung function evaluated by impulse oscillometry (airways resistance at 5 Hz [Rrs5], 10 Hz [Rrs10], and the difference of Rrs5 and Rrs20 Hz [Rrs5-20]), and with exhaled nitric oxide (FeNO) were evaluated after adjustment for confounders including height, sex, and body mass index z-score, and for additional covariates that could affect airway function. Results Total airway dysfunction represented by Rrs5 was reduced in participants with low serum iron level (a beta: -0.13, 95% CI: -0.23 to -0.03, p = 0.040) after adjustment for key confounders, but did not correlate with other iron profiles. Reduced oscillometric lung function recorded as Rrs5-20 was related with low serum iron and high serum ferritin, but the results were inconsistent after multiple comparisons. Associations were not observed with serum hemoglobin. Conclusions Decreased serum iron level was related with airway dysfunction represented as oscillomteric Rrs5. Our results suggest a relationship of reduced lung function with abnormal iron status in children.