Characteristics of study subjects
We recruited 487 fifth- and sixth-grade students for this study (Table 1). The average age was 11.01 years (95% CI: 10.9 to 11.1) and the average BMI z- score was −0.02 (95% CI: −0.11 to 0.07). Fifty-six children (11.7%) had wheezing at some time, 28 (5.8%) had asthma, and 25 (10.9%) were born premature and/or had low birth weight. A total of 61.4% of the children had atopic sensitization. The median level of serum periostin was 35.7 (ng/mL) and the median level of YKL-40 was 21.47 (ng/mL). Table 1 shows the IOS parameters.