Background and Aims
Obesity has been linked with asthma symptoms, need for asthma treatment and reduced lung function but not with increased bronchial reactivity in children. The aim of this study was to evaluate the association between previous or current weight status and current lung function and bronchial reactivity to exercise at early school age.
Methods
Ninety‐nine children hospitalized for bronchiolitis at the age of less than 6 months were studied with impulse oscillometry (IOS) at the mean age of 6.3 years. Data on birth weight and weight gain in infancy before hospitalization were collected during hospitalization. Current weight and height data were transformed into age‐ and sex‐specific height‐related body mass index z scores (zBMI) using the Finnish national population‐based weight and height data as reference.
Results
Some significant though only low or modest correlations were found between current zBMI and baseline, post‐exercise and post‐bronchodilator IOS values in adjusted linear regression analysis. Seven obese children by zBMI had higher post‐bronchodilator airway impedance (Zrs) and resistance (Rrs) at 5 Hz and lower post‐bronchodilator frequency dependency of resistance (dRrs/df) than normal weight children. There were no significant differences in responses to exercise or to bronchodilators between currently obese or overweight children and normal weight children. Birth weight less than 3,000 g was associated with larger exercise‐induced changes in Zrs and Rrs at 5 Hz, and in reactance (Xrs) at 5 Hz, than those with birth weight more than 3,000 g.
Conclusions
Preliminary evidence was found that obesity may be associated with airway obstruction, but not with bronchial hyper‐reactivity. Pediatr Pulmonol. 2015; 50:908–914. © 2014 Wiley Periodicals, Inc.