Opinion piece
Swimming pools and asthma: A new risk or premature concern?
Laura Downing
University of Pennsylvania, Philadelphia PA, United States of America
PP: 225 - 226
Article Text
Swimming has been a popular sport among the young and old for years; a near rite of summer passage. However it has recently been called into question by reports linking the chlorine in pool water to adverse respiratory effects and an increased risk of asthma, sending off alarm bells among parents and asthmatics alike. Indeed swimming has long been recommended as a well-tolerated activity for asthmatics due to the warm, humid environment, decreased asthmagenecity, and its positive cardiovascular effects. To raise public concern at this point, without solid, reproducible evidence of harm is irresponsible and premature; it may even cause greater detriment in the opportunity lost of benefi cial swim programs.
As childhood asthma prevalence rates and asthma-related hospitalizations continue to set record highs (Akinbami, 2006), the issue of asthma pathogenesis is undeniably a pressing one. With regard to indoor swimming pools, the issue of concern behind the pool-chlorine hypothesis is not the chlorine itself, but rather the inhalation of so-called volatile chlorinated disinfection by-products (DBPs; Bernard et al., 2003). A seminal report by the World Health Organization (2000) established that many of these DBPs are known irritants and potential carcinogens. While large, singular exposure to DBPs is accepted as being toxic to the respiratory system, the effect of chronic exposure to far smaller amounts remains unclear.
In support of this pool-chlorine hypothesis lies ongoing research showing links between chlorinated swimming pool attendance, atopic status, and asthma risk among infants, children, and adolescents (Bernard, Carbonnelle, De Burbure, Michel, & Nickmilder, 2006; Bernard, Carbonnelle, Dumont, & Nickmilder, 2007; Bernard, Nickmilder, Voisin, & Sardella, 2009). These studies appropriately raise the question of whether the increasing incidence of childhood asthma in industrialized countries can be at least partially explained by pulmonary epithelial changes secondary to DBP exposure (Bernard et al., 2003), and provide data to back their claim. Nevertheless, these studies are easily picked apart, and have such major faults in study design or study quality to be of any real value. In fact, at present, there is zero prospective data available on the subject (Weisel et al., 2009). A definitive meta-analysis by Goodman and Hays (2008) concluded that there is no consistent link in the research between childhood swimming pool use and asthma prevalence.
Despite the growing clamor of some, we must also not forget the beneficial effects of swimming programs on young asthmatics. Such programs improve physical health and respiratory status, and have been shown to decrease hospitalizations, emergency department visits, and loss of school days, while increasing self-esteem and self-confidence in the child (Huang, Veiga, Sila, Reed, & Hines, 1989). Furthermore, they can have positive effects on quality of life for the entire family, resulting in better overall asthma management, decreased need for medication, and increased participation by the child in other athletic and non-athletic activities (Wardell, Huang, & Isbister, 2006). These benefits are not insignificant and should not be overlooked for as yet unfounded claims regarding DBP exposure.
As an exact cause of asthma remains elusive, it is imperative that we examine the etiology of the disease and its associated risk factors from all angles. It is too soon to start ringing alarm bells and generating concern among the public; one word of the mere potential of 'toxic' exposure and parents will be withdrawing their kids valuable swim programs. There has already been a call for more detailed and reproducible prospective research on the link between swimming pool exposure and asthma (Weisel et al., 2009). It is time for us to sit and wait until the facts are in front of us, and a truly evidence-based recommendation can be made.
References
Akinbami, L. J. (2006). The state of childhood asthma, United States, 1980-2005. Advance data from vital health and statistics (no. 381). Hyattsville, MD: National Center for Health Statistics. Retrieved on October 15, 2009, from http://www.cdc.gov/nchs/data/ad/ad381.pdf
Bernard, A., Carbonnelle, S., De Burbure, C., Michel, O., & Nickmilder, M. (2006). Chlorinated pool attendance, atopy, and the risk of asthma during childhood. Environmental Health Perspectives, 114(10), 1567-1573.
Bernard, A., Carbonnelle, S., Dumont, X., & Nickmilder, M. (2007). Infant swimming practice, pulmonary epithelium integrity, and the risk of allergic and respiratory diseases later in childhood. Pediatrics, 119(6), 1095-1103.
Bernard, A., Carbonnelle, S., Michel, O., Higuet, S., de Burbure, C., & Buchet, J. P., et al. (2003). Lung hyper-permeability and asthma prevalence in schoolchildren: Unexpected associations with the attendance at indoor chlorinated swimming pools. Occupational and Environmental Medicine, 60(6), 385-394.
Bernard, A., Nickmilder, M., Voisin, C., & Sardella, A. (2009). Impact of chlorinated swimming pool attendance on the respiratory health of adolescents. Pediatrics, 124(4), 1110-1118.
Goodman, M., & Hays, S. (2008). Asthma and swimming: A meta-analysis. Journal of Asthma, 45(8), 639-647.
Huang, S. W., Veiga, R., Sila, U., Reed, E., & Hines, S. (1989). The effect of swimming in asthmatic children: Participants in a swimming program in the city of Baltimore. Journal of Asthma, 26(2), 117-121.
Wardell, C., Huang, S. W., & Isbister, C. (2006). When children with asthma go swimming, the benefits can be many and long-lasting. Contemporary Pediatrics, 23(10), 89-96.
Weisel, C. P., Richardson, S. D., Nemery, B., Aggazzotti, G., Baraldi, E., Blatchley, E. R., et al. (2009). Childhood asthma and environmental exposures at swimming pools: State of the science and research recommendations. Environmental Health Perspectives, 117(4), 500-507.
World Health Organization. (2000). International programme on chemical safety, environmental health criteria 216: Disinfectants and disinfectant by-products. Geneva: World Health Organization. Retrieved on October 15, 2009, from http://whqlibdoc.who.int/ehc/WHO_EHC_216.pdf
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