Objective: In this study, we aimed to compare the prevalances of asthma, allergic rhinitis and chronic bronchitis in 13-15 years old school children living in the rural and urban areas of Tokat city from the Black Sea region, and to evaluate the impact of household and children characteristics on prevalences of allergic diseases in order to question the hygiene hypothesis.

Materials and Methods: The study was conducted in the urban and rural parts of Tokat in 13-15 years old school children. The questionnaire included the ISAAC (International Study of Asthma and Allergy in Childhood) phase I questions. The items asking for chronic bronchitis and household characteristics were also included.

Results: Eight hundred eighty (81%) children from the urban and 210 (19%) children from the rural Tokat were included in the study. In the study population, the prevalences of wheeze, ever and current (last 12 months), were 17% and 10.4%, respectively and both symptoms were significantly more common in the urban. The rate of physiciandiagnosed asthma was 17.8% and there was no significant difference with respect to gender and place of residence. Chronic bronchitis was present in 25.6% of cases and were significantly more common in the urban and among the girls. Physiciandiagnosed allergic rhinitis was 10.4% in the total population and significantly more common in the rural (16%). Factors like gender, having an older sibling, sharing bedroom by siblings, and having a pet, were not found to be risk factors for wheezing, asthma and allergic rhinitis. The parental atopy was a risk factor for allergic rhinitis, and smoking at home for current wheeze was a risk factor in the urban. The presence of carpets on the floor was found to be a significant risk for wheezing and physiciandiagnosed asthma in the urban.

Conclusion: The prevalences of wheezing, asthma and allergic rhinitis in 13-15 years old school children in Tokat were in accordance with the studies carried out in costal cities of Black Sea region. Allergic rhinitis was significantly higher in the rural areas and having older sibling and sharing the bedrooms were found to be nonprotective for allergic diseases, all of which were contradictory to hygiene hypothesis. These results suggest that there might be some other unknown factors influencing the interactions between the genetics and the environment, that cause allergic diseases.