Proportion of community-acquired pneumonia cases attributable to tobacco smoking

Study objectives: To assess the population-attributable risk (PAR) of smoking and the effect of tobacco smoking on the development of community-acquired pneumonia (CAP) in adults, Design: A population-based case-control study, Information on history of smoking and other risk factors was obtained by a questionnaire administered by interview. Setting: Mixed residential-industrial area having 74,610 adult inhabitants in Barcelona, Spain. Participants: Two hundred five male and female patients (age, 15 to 74 years old) with CAP diagnosed between 1993 and 1995, They were matched to 475; control subjects randomly selected from the municipal census. Results: Smoking any type of tobacco had an odds ratio (OR) of CAP of 2.0 for ever smokers (95% confidence interval [CI], 1.24 to 3.24); 1.88 for current smokers (95% CI, 1.11 to 3.19); and 2.14 for ex-smokers (95% CI, 1.26 to 3.65). A positive trend for increased risk of CAP was observed for an increase in the duration of the habit, the average number of cigarettes smoked daily, and cumulative cigarette consumption. Former smokers had a 50% reduction in the OR 5 years after the cessation of smoking. The risk of CAP attributable to the consumption of any type of tobacco in this population was 32.4% of cases (95% CI, 14.8 to 50.1%). In subjects without a history of COPD, the PAR of tobacco was 23.0% (95% CI, 3.3 to 42.7%). Conclusion: This study gives better quantitative and qualitative evidence about the effects of tobacco smoking on the occurrence of pneumonia in the adult community.