• adult study;
  • atopic diseases;
  • chlorination by-products;
  • hay fever;
  • swimming pool attendance

Background:  Exposure to chlorination by-products through swimming pool attendance showed adverse health effects on children. The aim of our study was to assess whether pool attendance in childhood would be related to higher rates of allergic diseases in adulthood, with special regard to hay fever.

Methods:  2606 adults aged 35–74 years provided retrospectively collected information on swimming pool attendance and medical history, including data on atopic diseases. Information was assessed by a combination of a personal interview and a self-administered questionnaire. Logistic regression models were applied to study associations between hay fever and swimming pool attendance, adjusted for potentially relevant confounders, such as age, gender, region, education and smoking.

Results:  Higher rates of hay fever could be seen when frequently exposed at school age (aOR: 1.74, 95% CI: 1.09–2.77), frequently exposed during the past 12 months (aOR: 1.32, 95% CI: 0.92–1.89) and ever exposed (aOR: 1.65, 95% CI: 0.98–2.78). Strongest associations were found for the youngest subjects and were dose-related to the extent of current and school-age pool attendance.

Conclusions:  Impaired integrity of the lung epithelial by exposure to chlorination by-products might facilitate a closer contact to allergens and therefore could result in higher rates of hay fever.