Swimming in pools and hay fever risk

Children who go to swimming pools on a regular basis may be at risk for developing hay fever in adulthood. Chlorination by-products at swimming pools may damage the lining of the lungs, allowing closer contact to allergens and increasing the risk of hay fever. Hay fever is a disease with numerous potential influencing aspects, including lifestyle changes, environmental factors, allergen exposure and immunology. Contact with chlorination by-products might not be the leading reason for higher frequencies of hay fever, especially in adults, but might make up an important contribution to this multifactorial disease. Researchers from the GSF-National Research Center for Environment and Health in Neuherberg, surveyed 2,606 adults between 35 and 74 years of age. Personal interviews and questionnaires were used to gather detailed information about medical history and swimming pool attendance. It was found that subjects who attended a chlorinated swimming pool 3 to 11 times each year at school age were 74 percent more likely to develop hay fever than those who never attended a pool at school age. Recent exposure to a chlorinated swimming pool also increased the risk of hay fever. Subjects who reported exposure to a pool more than once a week for the last 12 months were 32 percent more likely to have hay fever than non-exposed individuals. Lastly, subjects who reported any lifetime exposure to chlorinated swimming pools were 65 percent more likely to have hay fever than individuals with no exposure. The associations with both recent and school-age pool attendance appeared to be dose-related. The above findings are consistent with past research linking exposure to chlorinated swimming pools with lung hyperpermeability, as well as exercise-induced cough and higher asthma rates.