Effect of obesity on bronchial hyperreactivity among Latino children

The association between obesity and bronchial hyperreactivity (BHR) in children has not been fully demonstrated in cross-sectional or longitudinal studies, and no study has specifically addressed Latino children.

A cross-sectional study of 450 children (10-18 years) from public schools was conducted in Mexico city. Among this group, 260 met the study criteria (no chronic respiratory illnesses, including asthma and rhinitis; no acute respiratory infections; and no tobacco-exposure or endocrine or body dysmorphic disorders), and 229 performed reproducible pulmonary function and methacholine challenge tests and were fully analyzed.

According to BMI percentiles, 40 were normal weight, 116 were obese, and 73 morbidly obese. Children in the morbidly obese group had significantly higher % FVC than those in the normal-weight group, and obese children had higher % PEF those in the morbidly obese and normal-weight groups. In the BHR methacholine challenge test, baseline FEV1 values among obese children were significantly lower than in the morbidly obese group. Using adjusted percentages for FEV1 , values were significantly lower among obese compared to morbidly obese children at metacholine concentrations of 0.25, 1, and 4 mg/ml. The proportion of positive BHR (PC20  ≤ 16 mg/ml) was higher in these two groups compared to normal-weight children (28.4%, 17.8%, and 12.5%, respectively), although differences were not significant.

Our findings show that obesity by itself is not a sufficient condition to alter airway responsiveness to methacholine in a group of adolescents.