Swimming was associated with rhinitis and pollinosis in a duration-dependent manner.

Background: Previous studies have reported conflicting results regarding the effects of childhood swimming on respiratory allergic symptoms. We investigated the relationship between swimming and respiratory allergic symptoms in schoolchildren.

Methods: A questionnaire regarding participation in sports club activities and respiratory allergic symptoms in schoolchildren was distributed to the parents of all 6853 public school students (aged 6-14 years) in Omihachiman City, Shiga, Japan. The relationships between participation in sports club activities and the prevalence of respiratory allergic symptoms were analyzed by multivariable logistic regression analyses.

Results: Questionnaires were returned for 4991 schoolchildren (response rate: 72.8%). Logistic regression analysis revealed significant positive associations between swimming and rhinitis (42.9% vs. 38.9%; adjusted odds ratio, 1.26; 95% confidence interval, 1.10-1.44), and swimming and pollinosis (32.1% vs. 28.1%; adjusted odds ratio, 1.28; 95% confidence interval, 1.11-1.47). The duration of participation in swimming activities was also significantly positively associated with the prevalence of rhinitis and pollinosis. Those who had participated in swimming activities for 6 years or more showed significantly higher prevalences of rhinitis and pollinosis (46.3% and 36.4%, respectively) than those without swimming activities (38.9% and 28.1%, respectively) and those who had participated in swimming activities for 5 years or less (40.1% and 28.5%, respectively).

Conclusions: Swimming was associated with the prevalence of rhinitis and pollinosis in schoolchildren, especially among those who had participated in swimming activities for 6 years or more. Preventive measures and early interventions for rhinitis and pollinosis should be recommended to these children.