Background: The prevalence of asthma depends on both hereditary and environmental factors. Knowledge of the effects of environmental and congenital factors on the frequency of occurrence of asthma may provide important clues to its pathogenesis and prevention.

Objectives: The Polish Multicentre Study of Epidemiology of Allergic Diseases was designed to obtain estimates representative of the entire Polish population to assess asthma prevalence and risk factors.

Methods: Thirty-three areas were selected in 11 regions of Poland. Epidemiologic diagnoses of asthma were verifi ed by a single recognized expert in each region on the basis of collected data as well as available medical documentation, in accordance with the1997 guidelines of the Global Initiative for Asthma. Ambient air concentrations of sulfur dioxide and suspended particulates (black smoke) were measured directly or estimated by statistical modelling.

Results: Results were obtained for asthma in 16 238 subjects, including 3268 children (aged 3 to 16 years) and 12 970 adults (17 to 80 years). The overall prevalence of asthma was 8.6% (95% confi dence interval [CI], 7.7% – 9.6%) among children and 5.4%
(95% CI, 5.0% – 5.8%) among adults. Several risk factors for asthma were identified: family history of asthma, black smoke, residential exposure to traffi c-related air pollution in both children and adults, and damp or overcrowded housing in adults. No statistically significant association was observed for passive smoking in the home, use of gas stoves, pet ownership, or exposure to ambient air pollution with sulfur dioxide.

Conclusion: Our results show that the prevalence of asthma is associated with several host and environmental factors in the Polish population.

Key words: Asthma. Prevalence. Risk factors. Poland.