Swimming pool attendance and risk of asthma and allergic symptoms in children.

Increased asthma risk has been associated with pool attendance in children but evidence is inconsistent and inconclusive. A survey was conducted of 3,223 9-12-yr-old children in Sabadell (Spain) to evaluate association between swimming pool attendance and prevalence of asthma and allergic conditions and symptoms. Parents completed a questionnaire on lifetime frequency of pool attendance and symptoms in the last 12 months (wheezing, asthma medication, rhinitis and allergic rhinitis), ever having asthma and eczema, and potential confounders. Indicators of indoor and outdoor swimming pool attendance early in life, cumulatively and currently were calculated. Swimming pool attendance before the age of 2 yrs was associated with slightly lower prevalence of current asthma (OR 0.79, 95% CI 0.43-1.46), rhinitis (OR 0.86, 95% CI 0.68-1.08) and allergic rhinitis symptoms (OR 0.72, 95% CI 0.54-0.96) compared to those who started attending swimming pools after 4 yrs of age. An increased prevalence of eczema was associated with duration of lifetime pool attendance (OR 1.71, 95%CI 1.38-2.12 for >5 yrs versus 0 yrs). Swimming pool attendance in Spanish children was associated with slightly less upper and lower respiratory tract symptoms and with more eczema. Longitudinal studies are required to confirm these findings and avoid potential reverse causation.