SMOKING AND BRONCHIAL RESPONSIVENESS IN NONATOPIC AND ATOPIC YOUNG-ADULTS

Background - Smoking may influence the response of the lungs to other inhaled substances. A study was undertaken to assess the effect of the interaction between smoking and the immunoresponse to common aeroalle rgens (atopy) on bronchial responsiveness. Methods - A random sample w as selected from the general population census of five areas of Spain (Albacete, Barcelona, Galdakao, Huelva, and Oviedo). A total of 1169 ( 35%) subjects completed a face-to-face respiratory questionnaire, a me thacholine bronchial responsiveness challenge, and underwent measureme nts of total and specific serum IgE levels to mites, pets and moulds. A survival model (Weibull) was used to examine the methacholine dose-r esponse relation, adjusting for bronchial obstruction. Results - Smoke rs showed greater bronchial responsiveness than never smokers (p <0.05 ) at any dose of methacholine, but only among non-atopic individuals. Atopy had a large effect on responsiveness at low levels of methacholi ne, but smoking did not increase responsiveness in atopic subjects. Th ere were no differences in intensity or cessation of smoking between a topic and non-atopic subjects, suggesting that smoking self-selection does not fully explain these results. Conclusions - The association be tween smoking and bronchial responsiveness varies with atopy, which ma y be explained by different immunological and/or inflammatory effects of smoking on atopy.