Effect of indoor air quality on the natural history of asthma in an urban population in Poland.

Background: Indoor air pollution may have an impact on asthma. Objective: To evaluate the influence of indoor air pollution on the natural history of asthma. Methods: Data collection by using the European Community Respiratory Health Survey and International Study of Asthma and Allergies in Childhood standardized questionnaire (N = 18,617) and medical examinations (N = 4783) in selected Polish regions was used. Statistical analysis was performed by using the χ² test. A value of p < 0.05 was considered statistically significant. Results: Questionnaire results demonstrated that people who used the central heating system were less likely to declare the occurrence of asthma (odds ratio [OR] 0.84) and were corroborated with clinical findings of moderate asthma (OR 0.35). Symptomatic asthma occurred more frequently in people who used a solid-fuel heating device (OR 1.36) and electric heaters (OR 1.54). The use of cooking appliances with municipal natural gas (OR 1.77) and gas storage tanks (OR 2.03) was correlated with more frequent declarations of asthma. Symptomatic asthma was more common among people who smoked for at least 1 year (OR 2.26) and those who smoked over the course of the preceding month (OR 1.60). Passive exposure to tobacco smoke provided for a 1.5-fold increase in the incidence of symptomatic asthma (OR 1.53), regardless of the time of exposure. Conclusion: Both active and passive tobacco smoke exposure as well as the use of certain types of heating and cooking appliances have a significant impact on the incidence of asthma and the intensification of its symptoms in rooms with limited air exchange. Highlights of the study included the following: (1) central heating had an amelioratory effect on asthma, (2) heating technologies used at home had a significant impact on the incidence of asthma, and (3) devices used for cooking (municipal and cylinder gas stoves) played an important role in the intensification of asthma symptoms.