Confronting the effects of smoking and air quality on the development of chronic respiratory diseases.

The main purpose of the paper was to compare the effects of outdoor and indoor air quality on the development of chronic respiratory diseases measured in the prospective study of chronic chest diseases among the inhabitants of Cracow, Poland. The 5-year follow-up study covered a probability sample of 4355 adult inhabitants. Data on respiratory symptoms and lung function in addition to variables related to environmental and socioeconomic factors were included. To assess the separate and joint effects of the chosen environmental factors on chronic chest problems, the multiple logistic regression analysis has been carried out. As expected, smoking habit was the strongest single of the factors related to the persistence of the respiratory symptoms. The effect of smoking was more marked in men than in women and this can be attributed to longer duration of smoking and more cigarettes smoked daily by men. Out of all considered adverse occupational factors only chemicals increased the risk of chronic bronchitis in men while dust increased the risk of exacerbations in women. The data showed a significant decrease in risk of exacerbations among the women who used a gas stove for cooking. The study also confirmed the harmful effect of smoking on lung function. Against this particular background the importance of variable temperature combined with ambient air pollution appeared to have rather strong detrimental biologic impact.