Impact of Chlorinated Swimming Pool Attendance on the Respiratory Health of Adolescents, 2009
Regulatory bodies and health authorities long have regarded the irritating effects of pool chlorine as a mere source of discomfort for swimmers, arguing that the dangers of chlorine, if any, must be weighed against the risks of inadequate disinfection and the health benefits of swimming. This way of reasoning, which has dominated swimming pool management for several decades, is being increasingly challenged by reports of health problems among swimmers. For several years, it has been known that elite swimmers have a higher prevalence of respiratory symptoms, asthma, and airway inflammation than do other athletes. Researchers increasingly acknowledge that these respiratory problems may be attributable, at least in part, to chlorine used to disinfect pool water. Public concern about the dangers of pool chlorine, however, was particularly aroused when it was found that indoor chlorinated pools may be detrimental to the airways of children, causing epithelial damage and increasing asthma risk.
Bernard et al. from the University of Louvain, Belgium, analyzed data on three groups of Belgian teenagers, two of which were exposed to chlorinated pools throughout life and throughout the test period. The third group was a reference group, as they had predominantly attended copper-silver pools and did so during the test period. Total and aeroallergen-specific immunoglobulin E (IgE) levels have been measured in serum and screened for exercise-induced broncho-constriction. Outcomes were respiratory symptoms: hay fever and allergic rhinitis. Also asthma that had been diagnosed at any time (ever asthma) or was being treated with medication and/or was associated with exercise-induced broncho-constriction (current asthma).
The study demonstrates that there is a pool chlorine-atopy interaction for asthma, and that this may extend to other common allergic diseases, such as hay fever and allergic rhinitis. In particular, the interaction between chlorine and atopy in the risk of hay fever was triggered by much lower CPA (chlorinated pool attendance) levels, compared with asthma and allergic rhinitis. The most important finding of this study is that attendance at chlorinated swimming pools, both indoor and outdoor, exerts a strong adjuvant effect that contributes significantly to the burden of asthma, hay fever, and allergic rhinitis during adolescence.
Studies by other investigators confirmed the respiratory effects of pool chlorine and provided additional evidence that chlorinated pools contribute to the development of allergic diseases. Initially, the respiratory problems of swimmers were attributed to the irritating effects of trichloramine, the gas that gives indoor pools their typical smell and can cause asthma in lifeguards.
However, the recent finding that asthma risk is increased similarly with attendance at outdoor pools demonstrates that trichloramine cannot be the only cause of respiratory effects in swimmers, because this highly volatile gas is quickly dispersed into the atmosphere when it is released outdoors. It evidences that chlorine in the water is as relevant in causing respiratory effects.
Source: published by the Official Journal of the American Academy of Pediatrics
Authors: by Alfred Bernard, PhD, Marc Nickmilder, PhD, Catherine Voisin, MSc, and Antonia Sardella, MD. (University of Louvain, Belgium)
