Chlorinated pool raises asthma risk

Swimming in a chlorinated pool may boost the risk of developing asthma and allergies among children with allergic sensitivities.

To see whether allergic diseases among adolescents are associated with chlorinated pool exposure, researchers from Belgium compared the health of 847 adolescents, 13 to 18 years old, who swam in chlorinated outdoor and indoor pools for various amounts of time with that of 114 adolescents who swam mostly in pools sanitised with a concentration of copper and silver. The second group served as the “control” group.

The researchers measured total and aeroallergen-specific immunoglobulin E (IgE) levels in blood and screened all participants for exercise-induced narrowing of the airways. They were also asked regarding any respiratory symptoms, hay fever, allergic rhinitis, and asthma that had been diagnosed at any time or was being treated with medication.

It was found that in children with allergic sensitivities, swimming in chlorinated pools significantly increased the likelihood of asthma and respiratory allergies. Among sensitive adolescents, the risk for hay fever was between 3.3- and 6.6-fold higher in those who swam in chlorinated pools for greater than 100 hours. The risk of allergic rhinitis was increased 2.2- to 3.5-fold among those who logged more than 1000 hours of chlorinated pool time.

The risk of asthma and allergy was not influenced by swimming in copper-silver sanitised pools and children without allergic tendencies were not at increased risk of developing allergies.

The findings indicate that exposure of  adolescents having an allergic tendency to chlorinated pool contributes significantly to the burden of asthma and respiratory allergies among them. This could be attributed to the fact that by irritating the airways of swimmers, chlorination products in water and air of swimming pools exert a strong additive effect on the development of asthma and respiratory allergies such as hay fever and allergic rhinitis.