Abstract
Objectives: To compare the exhaled carbon monoxide (CO) levels in apparently healthy smokers according to the intensity of cigarette consumption and verify its relationship with smoking habits and nicotine dependence.
Methods: Forty-four healthy smokers (20 male, 48±12 years, BMI: 27±4 kg/m2, 32±24 pack/years), without lung function impairment (FEV1/FVC: 80±6; FEV1: 82±20%pred) were divided into 3 groups according to their consumption of cigarettes/day: light smokers (G1): 1-15; moderate smokers (G2): 16-25 and heavy smokers (G3): over 25. The CO was assessed using a CO monitor (MicroCO®) after 10±1.2 hours of cigarette abstinence. In addition, smokers answered a questionnaire of smoking habits and the Fagerström Tolerance Questionnaire (FTQ) for nicotine dependence.
Results: Median [interquartile range] levels of CO were 10 [6-11], 10 [6-17] and 20 [12-24] ppm for G1, G2 and G3, respectively. There was significant difference in CO levels between G1 and G3 (p=0.001), G2 and G3 (p=0.013) but not between G1 and G2 (p=0.138). When analyzing the relationship between CO levels of smokers as a whole with smoking habits and nicotine dependence, modest correlations were found with number of cigarettes smoked in the last 24h (r=0.54, p<0.001), cigarettes/day (r=0.53, p<0.001), FTQ (r=0.33, p=0.02), pack-years (r=0.32, p=0.03) and time since last cigarette smoked (r =-0.31, p=0.04). These relationships were not found when assessing each group separately.
Conclusions: Exhaled CO levels are higher in heavy smokers in comparison to moderate and light smokers, whereas no difference was found between moderate and light smokers. Moreover, CO levels are related with smoking habits and nicotine dependence.
- © 2011 ERS
