PT - JOURNAL ARTICLE AU - Aretusa Cardoso AU - Renato Paceli AU - Gustavo Prado AU - Stella Martins AU - Mario Terra Filho AU - Ubiratan Santos TI - Biomarkers of smoking on post-ban era DP - 2014 Sep 01 TA - European Respiratory Journal PG - P4181 VI - 44 IP - Suppl 58 4099 - http://erj.ersjournals.com/content/44/Suppl_58/P4181.short 4100 - http://erj.ersjournals.com/content/44/Suppl_58/P4181.full SO - Eur Respir J2014 Sep 01; 44 AB - The ban on smoking indoors is significantly changing the profile of cigarette consumption; people are smoking less during the day and shifting their consumption to nighttime. Exhaled carbon monoxide (exCO) is a widely used, easy performed and instantaneously acquired biomarker of tobacco exposure, but its concentration may suffer the effects of a considerably large number of variables.The purposes of this study were to compare the exCO between self-reported smokers and nonsmokers, to reassess the most accurate cutoff value, and to calculate the effects of usual cigarette consumption (UC), punctual (day of consultation) consumption (PC) and time from last cigarette (TLC) in exCO.This cross-sectional study recruited volunteers to respond a brief questionnaire and to be submitted to exCO measurement with the MicroCo device.There were 181 males and 282 females. Mean age was 52 years. There were 165 smokers, 108 nonsmokers and 190 ex-smokers. Median exCO (ppm) was 13 among smokers vs. 3 among nonsmokers (p<0.001). There were not significant differences in exCO attributable to second hand smoke. A positive correlation was found between exCO and both UC (r2=0.431, p<0.001, βregression=0.133) and PC (r2=0.568, p<0.001, βregression=1.14) and a negative correlation was observed between exCO and TLC (r2=-0.489, p<0.001, βregression=-0.015. The most accurate cutoff for detecting nonsmokers was 6 ppm.Conclusion: exCO is influenced by UC, PC and TLC. Besides the accuracy of the 6ppm-cutoff, these independent variables must be considered when we face to unexpected exCO values in daily practice, especially with the recent changes in the pattern of cigarette consumption observed after the ban on smoking indoors.