Tobacco Patterns and Risk of Chronic Obstructive Pulmonary Disease: Results From a Cross-Sectional Study

There is still uncertainty about which aspects of cigarette smoking influence the risk of Chronic Obstructive Pulmonary Disease (COPD). The aim of this study was to estimate the COPD risk as related to duration of use, intensity of use, lifetime tobacco consumption, age of smoking initiation and years of abstinence.

We conducted an analytical cross-sectional study based on data from the EPISCAN-II study (n=9092). All participants underwent a face-to-face interview and post-bronchodilator spirometry was performed. COPD was defined as post-bronchodilator FEV1/FVC<70%. Parametric and nonparametric logistic regression models with generalized additive models were used.

8819 persons were included; 858 with COPD and 7961 without COPD. The COPD risk increased with smoking duration up to ≥50 years [OR 3.5 (95% CI: 2.3-5.4)], with smoking intensity up to ≥39cig/day [OR 10.1 (95% CI: 5.3-18.4)] and with lifetime tobacco consumption up to >29 pack-years [OR 3.8 (95% CI: 3.1-4.8)]. The COPD risk for those who started smoking at 22 or later was 0.9 (95% CI: 0.6-1.4). The risk of COPD decreased with increasing years of cessation. In comparison with both never smokers and current smokers, the lowest risk of COPD was found after 15-25 years of abstinence.

COPD risk increases with duration, intensity, and lifetime tobacco consumption and decreases importantly with years of abstinence. Age at smoking initiation shows no effect. After 15-25 years of cessation, COPD risk could be equal to that of a never smoker. This work suggests that the time it takes to develop COPD in a smoker is about 30 years.