Allergic diseases and atopy in elite swimmers: a cross-sectional study

Environmental exposure to irritants may contribute to asthma pathogenesis through increased epithelial permeability. This study aimed to investigate the association between chlorinated swimming pool exposure and allergic diseases, as well as its relationship with objective markers of airway inflammation, epithelial permeability, bronchial hyperreactivity, and atopy in elite swimmers. This cross-sectional study was conducted among pediatric swimmers attending a professional swimming club in Istanbul. All eligible participants were invited to complete the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. A subset underwent objective assessments, including exercise-induced bronchoconstriction testing, measurement of fractional exhaled nitric oxide (FeNO), serum surfactant protein-D (SP-D), serum club cell protein (CC16), and total and aeroallergen-specific immunoglobulin E (IgE) measurements. Of the 172 invited children, 169 (98%) completed the questionnaire, and 84 (49%) underwent objective assessments (44% male; mean age 10.0 ± 2.1 years). The median duration of swimming and cumulative pool attendance were 36 months and 1430 h, respectively. The prevalence of atopy was 41.6%. Among the participating swimmers, the prevalence of asthma (ever, current, and physician-diagnosed) was 25%, 9.5%, and 15.5%, respectively. Corresponding prevalences for eczema were 16.7%, 4.8%, and 7.1%, and for allergic rhinitis were 19.0%, 19.0%, and 16.7%. Cumulative exposure to chlorinated swimming pools was not associated with allergic diseases, airway inflammation, epithelial permeability, or bronchial hyperreactivity. However, children who had been swimming for more than 72 months demonstrated higher rates of atopy and current allergic symptoms.

In this cohort of elite swimmers, cumulative exposure to chlorinated swimming pools was not associated with allergic diseases or objective markers of airway inflammation. However, given the cross-sectional design, these findings should be interpreted with caution. The observed association between longer swimming duration and atopy appears to be exploratory. Overall, chlorinated pool exposure alone may be unlikely to be a major determinant of allergic disease in this population.

• Chlorinated pool exposure has been proposed to contribute to asthma and allergic diseases through airway epithelial injury; however, findings in pediatric populations are inconsistent, and many studies rely primarily on questionnaire-based data without objective airway assessments.

• In this cohort of elite swimmers, cumulative pool exposure was not associated with allergic diseases or objective markers of airway inflammation and epithelial integrity. However, longer swimming duration was associated with increased atopy, and subgroup analyses suggested that early-life exposure in combination with tobacco smoke may influence airway inflammation.