Objective: To ascertain the differences in smoking characteristics between a group of smokers with COPD and another group of healthy smokers, both of which were identified in a population-based epidemiologic study.
Design and participants: This is an epidemiologic, multicenter, population-based study conducted in seven areas of SPAIN: A total of 4,035 individuals, men and women aged 40 to 69 years, who were selected randomly from a target population of 236,412 subjects, participated in the study.
Interventions: Eligible subjects answered the European Commission for Steel and Coal questionnaire. Spirometry was performed followed by a bronchodilator test when bronchial obstruction was present. The Fagerström questionnaire was used for study of the degree of physical nicotine dependence, and the Prochazka model was followed for analysis of the smoking cessation phase.
Results: Of 1,023 active smokers, 153 (15%) met the criteria for COPD. Smokers with COPD were more frequently men (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.21 to 3.95), were > or = 46 years of age (OR, 1.97; 95% CI, 1.18 to 3.31), had a lower educational level (OR, 1.96; 95% CI, 1.23 to 3.14), and had smoked > 30 pack-years (OR, 3.70; 95% CI, 2.42 to 5.65). Smokers with COPD showed a higher dependence on nicotine than healthy smokers (mean [+/- SD] Fagerström test score, 4.77 +/- 2.45 vs 3.15 +/- 2.38, respectively; p < 0.001) and higher concentrations of CO in exhaled air (mean concentration, 19.7 +/- 16.3 vs 15.4 +/- 12.1 ppm, respectively; p < 0.0001). Thirty-four percent of smokers with COPD and 38.5% of smokers without COPD had never tried to stop smoking.
Conclusions: Smokers with COPD have higher tobacco consumption, higher dependence on nicotine, and higher concentrations of CO in exhaled air, suggesting a different pattern of cigarette smoking. Cases of COPD among smokers predominate in men and in individuals with lower educational levels. A significant proportion of smokers have never tried to stop smoking; thus, advice on cessation should be reinforced in both groups of smokers.