Children with allergic sensitivities (atopy) who have spent more time in chlorinated pools have a higher risk of asthma and nasal allergies, such as allergic rhinitis and hay fever, researchers from Belgium report in the Sept. 14 issue of Pediatrics.
The researchers, led by Alfred Bernard, PhD, of Catholic University of Louvain in Brussels, Belgium, examined 847 students aged 13 to 18 who went swimming in outdoor and indoor chlorinated pools.
Among kids with atopy, the odds for asthma increased with the lifetime number of hours spent in chlorinated pools, reaching sevenfold to 14-fold when chlorinated pool attendance exceeded 1,000 hours compared to adolescents who had less than 100 hours of chlorinated pool exposure.
Adolescents with atopy and greater chlorinated pool exposure also had increased risk of nasal allergies.
The researchers note that chlorine and its by-products can irritate the skin, eyes, and upper respiratory tract. "The chlorine-based oxidants in water or air floating at the pool surface cause some airway changes and promote the development of allergic diseases," they write in the study.
The researchers urge for additional studies and enforcement of regulations regarding chemicals in pools.