The prevalence of childhood asthma and wheeze rises around 2% to 3% for every indoor swimming pool per 100,000 of the population across Europe, indicates research published ahead of print in Occupational and Environmental Medicine.
The researchers analyzed the rates of wheezing, asthma, hay fever, allergic rhinitis, and atopic eczema, reported in the International Study of Asthma and Allergies in Childhood (ISAAC), by video or written questionnaire.
After taking account of potential influential factors, such as the gross domestic product (GDP) of a country, climate, and altitude, the prevalence of asthma and wheeze was strongly associated with the number of indoor pools per 100,000 of the population.
The findings showed a clear European East-West divide in indoor pool availability and rates of asthma. The rate of wheezing rose by 3.39% for every additional indoor chlorinated swimming pool. Similarly, the rate of asthma rose by 2.73%.
The authors conclude that the rise of asthma in Western Europe could at least partly be attributed to the increasing exposure of children to the by-products of chlorine in the air and water of indoor swimming pools.
They suggest that the long term effects of chlorine by-products on children’s respiratory health should be thoroughly evaluated, and that pools should be properly ventilated and levels of chlorine by-products regulated.