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.