Swimming pool attendance and exhaled nitric oxide in children

Bernard et al2 recently showed that, in children who regularly attend swimming pools, serum surfactant proteins, biomarkers of lung epithelial damage, are increased, and their concentrations correlate with serum IgE levels. [...]these authors found a significant association between asthma prevalence and swimming pool attendance, suggesting that repeated exposure to chlorine derivatives can predispose to asthma development.2,4 Exhaled nitric oxide (NO) levels are significantly increased in asthmatic patients, and they are considered an accurate biomarker of eosinophilic airway inflammation.5,6 The maneuver required to measure exhaled NO is quick and can easily be performed by children starting from the age of 4 years.7 Moving from the above-reported findings, we hypothesized that if chlorine exposure is associated with asthma development, then increased concentrations of exhaled NO, as a marker of eosinophilic airway inflammation, should be detectable in children regularly attending swimming pools.