| Abstract |
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[eng] Swimming pools are mainly disinfected by chlorination, which leads to the formation of unwanted harmful products. In a first sudy initially planned to evaluate the respiratory effects of air pollution in children living in Brussels, attendance at chlorinated pools appeared to be associated with lung hyperpermeability. A retrospective analysis of data on asthma prevalence in children brought to light an increased risk of asthma with cumulative attendance at the chlorinated school pool. To further investigate these findings, several studies were carried out. Chronic studies specifically designed to investigate the relationship between chlorinated pool attendance and the risk of asthma confirmed the association. Whilst the risk of lung inflammation assessed by the measurement of exhaled nitric oxide increased with cumulated chlorinated pool attendance in all children, the risk of developing asthma was only increased in atopic children (with a level of serum IgE >100 kIU·L-1). These effects were strongly linked to pool attendance before the age of 6-7 years. Infant swimming practice was identified as a high risk activity, leading to airway changes that seem to promote the onset of asthma and recurrent bronchitis later in childhood. Short-term studies in recreational and trained swimmers also revealed an increased permeability of the lung epithelium. This finding was confirmed in mice acutely exposed to a controlled concentration of nitrogen trichloride. Inflammatory effects were also studied in trained swimmers. The physiological lung inflammation normally observed during exercise and assessed by exhaled nitric oxide was inhibited in chlorinated atmosphere. No change was detected in lung function or in lung epithelium permeability in this study where levels of trichloramine were low (<300 ìg/m³). In conclusion, attendance at chlorinated pools clearly acts as an adjuvant in the development of asthma in atopic subjects. Infant swimming practice is also detrimental to respiratory health. Therefore, it is recommended not to take children too early to swimming pools and to be particularly cautious in case of atopic children. At least, children should only attend well-managed pools, to avoid jeopardizing their respiratory health. |
