Evaluation of smoking status: comparison of self-reports with exhaled carbon monoxide analysis in university students in the Islamic Republic of Iran.

BACKGROUND: Smoking is considered the leading risk factor for many chronic diseases and deaths worldwide. Thus, it is important to determine the number of smokers before implementing tobacco control initiatives. Due to stigma and deterrent measures, it is impossible to access smokers through a self-report questionnaire. AIMS: To compare exhaled carbon monoxide levels with self-reports among university students in the Islamic Republic of Iran. METHODS: This cross-sectional study included a convenience sample of 60 university students recruited in 2016 in Tehran. There were 30 women and 30 men with an average age of 23.1 (±15.6) years. They were interviewed using an adaptation of the International Union Against Tuberculosis and Lung Diseases questionnaire and further assessed by breath analysis. Smoking status was compared and then correlated with the resultant carbon monoxide levels at a cutoff of 6 ppm. RESULTS: Mean cigarette consumption was 4.7 (±1.8) each day and smoking status was reported as 19 (31.7%) current smokers and 41 (68.3%) nonsmokers of tobacco. Significant correlations were obtained between the exhaled carbon monoxide levels of the smoker and nonsmoker groups (P < 0.05). Irrespective of the measures of smoking status, the frequency of detecting smokers was comparable to that of detecting nonsmokers (P = 0.756). CONCLUSIONS: Similar to self-reports, the exhaled carbon monoxide measurement successfully distinguished smokers from nonsmokers. This allows healthcare providers and policy-makers to examine the effectiveness of tobacco cessation and prevention programmes.

New Biomarkers Based on Smoking-Related Phenotypes for Smoking Cessation Outcomes of Nicotine Replacement Therapy: A Prospective Study.

INTRODUCTION: Identifying a potent biomarker for smoking cessation can play a key role in predicting prognosis and improving treatment outcomes. This study aimed to evaluate the contribution of new biomarkers based on the levels of Cotinine (Cot) and carbon monoxide (CO) to the short- and long-term quit rates of nicotine replacement therapies (Nicotine Patch [NP] and Nicotine Lozenge [NL]). METHODS: In this prospective interventional study, 124 smokers under treatment with the 5A's method were selected from an outpatient smoking cessation center in district 18 of Tehran City, Iran. The study was conducted from April 2016 to December 2018. They were divided into NP (n=56) and NL (n=61) intervention groups. The levels of Cot and CO were measured using ELISA and breath analysis at the beginning of the study. Three markers were calculated: Cot/CO, Cot to cigarette per day ratio (Cot/CPD), and CO/CPD. Binary logistic regression models and generalized estimating equations models were analyzed by SPSS software, version 21 to determine the chances of quitting smoking. RESULTS: Of the NP participants, 30.4% and 19.6% were abstinent after 2 and 6 months, respectively, while NL was found less effective with 19.7% for 2-month follow-up and 13.1% for 6-month follow-up. The 6-month success of quitting attempts was significantly different for the NP participants at the second half of Cot/CO (P=0.029). Of the NL participants, CO/CPD would be a superior predictor for smoking cessation success (P>0.05). CONCLUSION: The findings of this study suggested two markers of Cot/CO and CO/CPD in this order for the optimum treatment outcomes of NP and NL.