An elevated body mass index increases lung volume but reduces airflow in Italian schoolchildren

Abstract

Background: Asthma and obesity are important and growing health issues worldwide. Obesity is considered a risk factor for asthma, due to the induction of changes in airway mechanics and altered airway inflammation. Methods: We cross-sectionally investigated the effect of increased weight on pulmonary function in a large population sample of healthy children, aged 10-17 yrs living in Palermo, Italy. Explanatory effect of weight on lung function variables were evaluated by multiple linear regression models, taking into account height, gender, and age-class. Results: Among the 2,393 subjects, FVC and FEV 1 were positively correlated to weight. Multiple regression models showed that the weight beta coefficient for FEV 1 was significantly lower with respect to that for FVC (0.005 and 0.009 l/kg, respectively), indicating a different magnitude in explanatory effect of weight on FVC and FEV 1. Both FEV 1 /FVC and FEF 25-75% /FVC ratios were negatively correlated to weight, while FEF 25-75% was not significantly correlated. Similar results were obtained also when 807 symptomatic subjects were introduced in the model through a sensitivity analysis. Conclusion: In healthy children, the disproportionate increase of FEV 1 and FVC with weight produces airflow decrease and consequently apparent poorer lung function independently from respiratory disease status.