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

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 FEV1 were positively correlated to weight. Multiple regression models showed that the weight beta coefficient for FEV1 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 FEV1. Both FEV1/FVC and FEF25-75%/FVC ratios were negatively correlated to weight, while FEF25-75% 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 FEV1 and FVC with weight produces airflow decrease and consequently apparent poorer lung function independently from respiratory disease status.

A cross-sectional study assessing the relationship between BMI, asthma, atopy, and eNO among schoolchildren.

BACKGROUND: Increased body weight may influence airway inflammatory mechanisms. OBJECTIVE: To assess whether overweight-obesity (OW-O), evaluated as increased body mass index, is associated either with exhaled nitric oxide (eNO), a marker of airway inflammation, or with allergic sensitization in a large sample of children and adolescents. METHODS: A cross-sectional, epidemiological study was performed on a population sample of schoolchildren evaluating 708 subjects (age 10-16 years; BMI 13-39 kg/m(2)) by respiratory health questionnaire, skin prick tests, spirometry, and eNO measure. RESULTS: Prevalence rates were: OW-O 16.4%, asthma ever (A) 11.9%, and rhinoconjunctivitis (RC) 14.8%. Asthma ever and allergic sensitization were significantly more frequent among OW-O (21.0 and 51.6%) than in non-OW-O (10.2 and 37.0%, respectively). The forced expiratory volume in 1 second (FEV(1))/forced vital capacity (FVC) ratio was not significantly different between OW-O and non-OW-O. Exhaled NO (median and interquartile range) was 15.3 (11.2-23.1) ppb in the overall sample, 20.3 (12.9-35.8) ppb among allergic subjects, and 13.9 (10.6-18.3) ppb among nonallergic subjects (P<.0001). No significant difference between OW-O and non OW-O subjects was found in eNO levels. Similarly, OW-O subjects with A or RC did not show significantly higher eNO levels than non-OW-O. In a logistic regression model, presence of allergic sensitization, A, and RC, and not OW-O, were significant predictors of increased eNO. CONCLUSIONS: In children, OW-O was not associated with increased eNO levels, but it was an independent risk factor for asthma and allergic sensitization.