IMPORTANCE OF SMOKING FOR CHLAMYDIA-PNEUMONIAE SEROPOSITIVITY

Background. Population-based studies of the association between smokin g and Chlamydia pneumoniae seropositivity do not exist. The role of sm oking in the association between C. pneumoniae seropositivity and coro nary artery disease (CAD) suggested by several studies has been debate d. The aim of this study was to determine the relationship between smo king habits and G. pneumoniae IgG antibody titres in a middle-aged pop ulation. We also wanted to find out whether the difference in smoking habits between the sexes explains the higher C. pneumoniae antibody pr evalence among men compared with women. Results. After controlling for the effect of smoking, the risk of C. pneumoniae seropositivity remai ned 1.4 times higher in men than in women. In men, the estimated risk for G. pneumoniae seropositivity (titre greater than or equal to 1:16) was significant only for smokers (adjusted odds ratio [OR] = 1.4). Th e adjusted OR for high seropositivity (titre greater than or equal to 1:128) was 1.5 for smokers and 1.7 for ex-smokers. The risk for women was similar to that for men. Conclusions. The results provide evidence of an association between smoking and C. pneumoniae seropositivity in the general population. The higher prevalence of smoking in men does not explain the C. pneumoniae antibody prevalence in men compared with women.