Epidemiologic studies on allergic diseases among rural and urban school children in Poland

451 rural children (group I) and 2000 urban children (group II) aged 10-16 years from Toruń province were inquired by a questionnaire to their parents or guardians. 9.09% of children in the country and 13.45% of those living in the city of Toruń suffered from hypersensitivity disorders; bronchial asthma was reported in 2.22% and 3.05% of cases, allergic rhinitis--in 3.77% and 7.15%, allergic conjunctivitis--in 1.33% and 2.75%, allergic edema--in 0.44% and 0.60%, urticaria--in 1.55% and 3.50%, and infantile eczema--in 0.44% and 2.10% of cases, respectively. The pollinosis prevalence rate was 2.00% in group I and 1.85% in group II. At least 2 various forms of hypersensitivity coexisted in 30.48% of allergic urban children (64.86% of patients with pollinosis among them); infantile eczema preceded allergic rhinitis and bronchial asthma symptoms in 6.29% and 11.47% of cases, respectively, while allergic rhinitis occurred before the onset of bronchial asthma in 24.59% of asthmatic children. 37.10% of individuals with positive family history of allergic conditions also fell ill with some diseases of this nature, while in those with negative family history allergy occurred only in 10.22% of cases. From environmental factors mother's diseases during pregnancy, bottle feeding and a regular diet during the first year of life, frequent respiratory infections in the early childhood and poor living conditions increased the risk of allergic diseases or aggravated their course in the population examined.