Objective: Studies investigating the lung function of school-age obese asthmatics are rare. The purpose of this study was to compare lung functions in school-age obese asthmatics with non-obese asthmatics.

Methods: Ninety-two children were assigned to obese asthmatics (OA group, n=43) and non-obese asthmatics (A group, n=49) groups. A baseline impulse oscillometry test was performed to measure lung functions.

Results: Baseline percent predicted value of R20 (p=0.025), R5-20 (p=0.040), and Fres (p=0.018) were significantly increased in obese asthmatics than non-obese asthmatics. AX was also higher in obese asthmatics compared to non-obese asthmatics, however, the difference was insignificant (p=0.787). Percent predicted value of R5 (p=0.007) and R10 (p=0.017) were higher in atopic than non-atopic obese asthmatics. Percent predicted value of R5 was higher in exercise-intolerant than exercise-tolerant non-obese asthmatics (p=0.045). Additionally, R10 was higher in non-obese asthmatics with household mold exposure than that without household mold exposure (p=0.045). The z scores of BMI or weight were correlated with none of the IOS parameters (p>0.05).

Conclusion: Main bronchial and peripheral airway resistance were higher in school-age obese asthmatics compared to non-obese asthmatics. Peripheral airway resistance was higher in atopic obese asthmatics as well as in exercise intolerant asthmatic children and those with household mold exposure.

Keywords: asthma, impulse oscillometry, lung function, obesity, children