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

321 Research article EMHJ – Vol. 27 No. 4 – 2021 Evaluation of smoking status: comparison of self-reports with exhaled carbon monoxide analysis in university students in the Islamic Republic of Iran Arash Nikkholgh,1 Matina Soleimani,2 Anahita Torkaman-Boutorabi1,3 and Behzad Valizadeh4 1Department of Neuroscience and Addiction Studies, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences-International Campus, Tehran, Islamic Republic of Iran (Correspondence to: Arash Nikkholgh: arash.nikkholgh@yahoo.com). 2Department of Psychology, Payame Noor University, Tehran, Islamic Republic of Iran. 3Research Center for Cognitive and Behavioral Studies, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran. 4National Tobacco Control Secretariat, Ministry of Health and Medical Education, Tehran, Islamic Republic of Iran. Abstract 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 deter- rent 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 smok- ers 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. Keywords: exhaled carbon monoxide, tobacco use, self-report, university students, Islamic Republic of Iran Citation: Nikkholgh A; Soleimani M; Torkaman-Boutorabi A; Valizadeh B. Evaluation of smoking status: comparison of self-reports with exhaled carbon monoxide analysis in university students in the Islamic Republic of Iran. East Mediterr Health J. 2021;27(4):321–326. https://doi.org/10.26719/emhj.20.121 Received: 06/03/19; accepted: 05/04/20 Copyright © World Health Organization (WHO) 2021. Open Access. Some rights reserved. This work is available under the CC BY-NC-SA 3.0 IGO license (https://creativecommons.org/licenses/by-nc-sa/3.0/igo) Introduction Smoking is the most prevalent, high-cost, and fatal form of drug dependence. Each year, > 8 million of the estimat- ed global 1.1 billion tobacco smokers die due to the use of nicotine-containing products (1). Mathers and Loncar (2) have reported that tobacco-related deaths will reach 8.3 million in 2030. Tobacco consumption accounts for 80– 90% of lung cancers (3) and leads to an increase in cancers of the larynx, mouth, oesophagus, pancreas, kidney, blad- der, and uterine cervix (4). In addition to cardiovascular and respiratory diseases, it can cause fetal abnormalities (1). Deaths caused by tobacco use are more than those linked to alcohol consumption, AIDS, vehicle accidents, substance abuse, crime and suicide combined (5). Tobac- co use has grown in low- and middle-income countries, and ~80% of smokers live in these regions (6). The tobac- co use epidemic has shifted to the developing world. Giv- en the young population density, the Islamic Republic of Iran demands special attention (7); in other words, the high number of adolescents in the country makes it into an ideal market for the tobacco trade. Determining smoking status is important in starting cessation interventions as well as monitoring progress (8). In epidemiological studies, validation and confirmation of cigarette smoking and nonsmoking are essential. The advent of electronic health records has facilitated obtaining updates on smoking status. However, this may not occur in reality due to the absence of approved terminology and granularity for data collection, changes in cultural attitudes toward tobacco use, and probable instability of smoking behavior (9,10). Tobacco exposure can be assessed by self-reports, which seem convenient, especially for extensive studies (11). Although self- reported smoking status is widely applied for assessing the prevalence of smoking, it underestimates the actual exposure (12), owing to the lack of social acceptance of smoking (13). As an alternative, many studies have used measure- ment of carbon monoxide (CO) in exhaled breath as a quick and noninvasive technique to verify smoking sta- tus (14). CO is a product of tobacco combustion (15), and exhaled CO is considered a specific biomarker of recent 322 Research article EMHJ – Vol. 27 No. 4 – 2021 smoking, with a half-life of 2–6 hours (16). Accordingly, the present study compared the self-reported cigarette smoking status with the results of exhaled CO testing in university students. This is believed to be the first study in the Islamic Republic of Iran to investigate the corre- lation between exhaled CO and self-reports of smoking. Methods Study design and participants This was a cross-sectional study conducted within a uni- versity setting. In November 2016, we used a nonrandom convenience sampling technique to select 60 students who read the study communiqués issued by the Depart- ment of Public Relations in the School of Advanced Tech- nologies in Medicine in Tehran, Islamic Republic of Iran. The recruitment was performed in person by research team members based on the following inclusion criteria: age 18–30 years and higher education to at least diploma level. There was an equal sex ratio, with 30 women and 30 men, with an average age of 23.09 [standard deviation (SD) 15.64] years. The exclusion criteria included pul- monary diseases, cognitive disorders, nicotine replace- ment therapy, renal failure requiring dialysis, and facial deformities that would cause problems in the use of spirometry or determination of the exhaled CO level (17). Determination of self-reported smoking status A self-administered Farsi-language smoking question- naire, adapted from the International Union Against Tuberculosis and Lung Diseases (18,19), was utilized, as in previous reports from the Islamic Republic of Iran (20). The questionnaire contained information on demo- graphics (age, residency and marriage) and tobacco use (4 questions), smoking status (4 questions), and smoking frequency (4 questions). Two supplementary questions were added concerning the age at starting smoking tobac- co. Six of the questions dealt with the pattern of smoking behavior, including one “yes/no” question about present cigarette smoking; 2 short answer questions about week- ly frequency of cigarette smoking; 2 short answer ques- tions about the type of cigarettes smoked; and 1 “multi- ple-choice question” about the time to first cigarette in the morning (ranging from < 5 minutes to > 1 hour). Exhaled breath CO analyzer The piCO+ Smokerlyzer (Bedfont Scientific, Maidstone, UK) was used to measure exhaled CO levels with stand- ardized smoking thresholds recommended by the man- ufacturer for different age categories. The test was con- ducted in the school hall by a trained research assistant. There was a breath sampling D-piece and a cardboard mouthpiece attached to the device before each test. In- itially, the ambient levels of CO were detected, and the machine was calibrated against the room air. The study participants were instructed to inhale and hold their breath while a 15-second countdown was started. Also, they were asked to blow into the mouthpiece as slowly and thoroughly as possible in an attempt to empty the lungs when the device alarm started. Finally, the students were given access to their test results. The breath tests were conducted in duplicate to ensure consistency. The breath analysis was repeated if the difference between the results was higher than 2 ppm. The exhaled CO levels were presented in ppm, with > 6 ppm being indicative of smoking. Procedure All participants were referred during November 2016 to the Health Counseling Room in the School of Advanced Technologies in Medicine for eligibility assessment by a physician and psychologist. The initial sample included 84 men and women, 60 of whom met the inclusion crite- ria. The other remaining 24 participants were prevented from continuing the study. Afterwards, the students were asked to participate in both interview and breath analy- sis. All interviewers were trained to ensure consistency and avoid bias. Those who reported any form of tobacco use in the preceding 24 hours were put in the category of smokers. The remaining students were considered non- smokers, including those who did not smoke in the last week or who had never smoked. Ethical considerations At the start of the study, written informed consent was obtained from all students. They were assured that the results would be confidential and reported anonymous- ly in an attempt to encourage accurate and thorough reporting of their smoking habits. The Research Ethics Committee of Tehran University of Medical Sciences ap- proved the study (code: IR.TUMS.REC.1394.18.96). Statistical analysis Data were collected and entered into SPSS version 22 software (SPSS Inc., Chicago, IL, USA) for further anal- yses. The data were described by descriptive statistics, including frequency, percentage, and mean (SD). The data distribution was investigated by performing the Kolmogorov–Smirnov test. Student’s independent t test was carried out for comparison of CO levels between the smoker and nonsmoker groups. The Pearson correlation coefficient was determined between them. The frequen- cy of smokers according to exhaled CO measurement was compared with that by self-reports using Pearson’s χ2 test. The effect of sex on the exhaled CO levels was evaluated by the Mann–Whitney U test. P < 0.05 was de- fined as statistically significant. Results The demographic characteristics of the university stu- dents are summarized in Table 1. They had a mean cig- arette consumption of 4.68 (1.79) each day, and a mean smoking initiation age of 19.43 (8.62) years. Among the 60 students, 319 (1.67%) had smoked tobacco within the last 24 hours and were assigned to the smoker group. A total of 41 participants (68.33%) self- reported no use of tobacco products in the last week or no 323 Research article EMHJ – Vol. 27 No. 4 – 2021 smoking at all, and they were placed in the nonsmoker group. In the smoker group, there were 14 (23.33%) men, aged 25.68 (11.21) years, and 11 (18.33%) were single. In the nonsmoker group, there were 16 (26.67%) men, aged 21.62 (19.04) years, and 34 (56.67%) were single. The smoker group tended to start smoking at a younger age compared with the nonsmokers [17.93 (6.22) vs 21.04 (13.51) years and reported smoking a higher number of cigarettes each day [5.79 (3.40) vs 4.11 (1.13) ]. The participants in the smoker group had an exhaled CO level of 13.57 (2.03) ppm, which was about 3 times higher than 4.44 (0.52) ppm in the nonsmoker group. The independent-samples t test showed that there was a significant difference in exhaled CO levels between the groups (t(58) = 19.84, P = 0.004). Moreover, the Pearson correlation coefficient between the exhaled CO levels of the 2 groups was 0.719 (P = 0.003). These results indicated that exhaled CO in current smokers could be distinguished from that in ex- or nonsmokers. The CO analyzer showed that 15 students had an average CO level > 6 ppm. The χ2 test revealed no marked association between the smoking status reported by the exhaled CO measurement and self-report (χ2 = 0.657, P = 0.418). In other words, the results of the exhaled CO measurement were in line with those of the self-report. The exhaled CO levels were 8.80 (1.0) ppm for men and 5.90 (0.60) ppm for women. Based on the Mann– Whitney U test, the male participants had a significantly higher concentration of exhaled CO (U = 47.000, P = 0.035) than the female participants. Discussion The prevalence of tobacco use was 31.67% among univer- sity students, which is consistent with other reports from the Islamic Republic of Iran (21–23). The mean number of cigarettes per day and smoking initiation age were 4.68 (1.79) and 19.43 (8.62) years, respectively. No study has investigated the average number of cigarettes per day for university students. However, a recent meta-analy- sis found a daily rate of 11.6 and 15.0 in Tehran Province (24). In the present study, men showed higher exhaled CO levels than the total participants (around 2-fold) and women (around 3-fold). These findings were consistent with the results reported by Moscato et al. (25); however, the CO values were not comparable between the studies. Typical exhaled CO values certainly differ across studies even if they used a piCO+ Smokerlyzer because mean lev- els in nonsmokers vary from < 1.5 ppm (26) to 3 ppm (27). These differences arise from factors such as disparity in environmental CO levels, anthropometric features (e.g., lung capacity), and measurement techniques (28). Raiff et al. showed that measures obtained from prolonged expiration led to higher values than those from shorter expiration (29). In this regard, the trend of the exhaled CO concentration during expiration may also play a role. Schober et al. suggested 3 phases for CO level (30). It is 0 in the primary part of the expiration (phase 1), followed by progressive increases (phase 2), and finally decreases after a plateau (phase 3). Moreover, considerable environ- mental CO levels could have explained the exhaled CO levels since our study was conducted in a large city, and the participants were exposed to air pollution caused by traffic jams, especially when traveling to the university. Individual subject variability [e.g., lung volume (28) and physical activity (31)] may influence CO measures but was not considered in our study. The present study showed that the breath analysis device could be used for accurate determination of tobacco use in adolescents with light smoking (around 5 cigarettes/day). Additionally, this device provided a reasonable alternative to self-reporting. Measurement of exhaled CO using this device at a cutoff point of 6 ppm sounds like a viable measure for distinction between current smokers and ex- or nonsmokers, as opposed to the self-reporting method. These findings were corroborated by previous investigations (32,33). This study had some limitations. The study dealt with a hidden problem in society, especially in universities; therefore, self-reported data faced challenges due to taboos Table 1 Participants’ demographics and smoking characteristics Characteristics Self-reported status of tobacco use Total n = 60Smoker n = 19 (31.67) Nonsmoker n = 41 (68.33) Age, years, mean (SD) 25.68 ± 11.21 21.62 ± 19.04 23.09 ± 15.64 Male, n (%) 14 (23.33) 16 (26.67) 30 (50) Residency, n (%) Individual home Parent’s home Dormitory 8 (13.33) 5 (8.33) 6 (10.00) 25 (41.67) 8 (13.33) 8 (13.33) 33 (55.00) 13 (21.67) 14 (23.33) Marriage, n (%) Divorced/widowed Married Single 1 (1.67) 2 (3.33) 11 (18.33) 1 (1.67) 5 (8.33) 34 (56.67) 2 (3.33) 7 (11.67) 45 (75.00) Smoking initiation age, years, mean (SD) 17.93 ± 6.22 21.04 ± 13.51 19.43 ± 8.62 Cigarettes per day, mean (SD) 5.79 ± 3.40 4.11 ± 1.13 4.68 ± 1.79 Results presented as number (%) SD = standard deviation. 324 Research article EMHJ – Vol. 27 No. 4 – 2021 surrounding women’s smoking. As a result, a combination questionnaire together with secret codes instead of names was used to reduce bias. Besides these, restrictions were undertaken to ensure data confidentiality. However, it is likely some of the participants might have avoided giving a socially undesirable response. Moreover, the cross-sectional study design made causal conclusions difficult. Small sample size was another limitation that should be resolved for future investigations. The use of biological measures like exhaled CO is associated with the limitation of measurement among different individuals and receiving false-positive reports. Other factors may have affected our results, such as a lack of financial resources, biological and social variations between the sexes, and poor collaboration from organizations. Additionally, a high number of questions took more time to respond than expected, which could have affected the 1 MPOWER = 1) Monitoring tobacco consumption and the effectiveness of preventive measures; 2) Protect people from tobacco smoke; 3) Offer help to quit tobacco use; 4) Warn about the dangers of tobacco; 5) Enforce bans on tobacco advertising, promotion and sponsorship; and 6) Raise taxes on tobacco. students’ response precision. Also, the results of this study can only be generalized to the university students selected here. In conclusion, the present study proposed that the exhaled CO levels measured by breath analysis could successfully discriminate current smokers from nosmokers, which is the same as self-reporting. Moreover, the use of exhaled CO allows healthcare providers and policy-makers to implement MPOWER1 measures, enhance the country-level achievements in interventions targeting the demand for tobacco products, and examine the effectiveness of tobacco use cessation and prevention programmes. Funding: None. Competing interests: None declared. Évaluation du statut tabagique : comparaison des informations auto-déclarées avec la mesure du monoxyde de carbone expiré chez les étudiants universitaires en République islamique d’Iran Résumé Contexte : Le tabagisme est considéré comme le principal facteur de risque de nombreuses maladies chroniques et de décès dans le monde. Il est donc important de déterminer le nombre de fumeurs avant de mettre en œuvre des initiatives de lutte antitabac. En raison de la stigmatisation et des mesures dissuasives, il est impossible d'accéder aux informations concernant le nombre de fumeurs par le biais d'un questionnaire d'auto-déclaration. Objectifs : Comparer les taux de monoxyde de carbone (CO) expiré avec les informations auto-déclarées par les étudiants universitaires en République islamique d'Iran. Méthodes : La présente étude transversale a inclus un échantillon de commodité de 60 étudiants universitairesrecrutés en 2016 à Téhéran. Il était composé de 30 femmes et de 30 hommes dont l'âge moyen était de 23,1 ans (±15,6). Les entretiens avec les participants se sont déroulés en utilisant une version adaptée du questionnaire de l’Union internationale contre la tuberculose et les maladies respiratoires ; une évaluation ultérieure a été réalisée au moyen d’une analyse de l’haleine. Le statut tabagique a été comparé et ensuite corrélé avec les taux de CO résultants à un seuilde 6 ppm. Résultats : La consommation moyenne de cigarettes était de 4,7 par jour (±1,8) et le statut tabagique était indiqué pour 19 fumeurs (31,7 %) et 41 non fumeurs (68,3 %) au moment de l’étude. 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J Pharmacol Pharmacother. 2011 Jul;2(3):174–8. http://dx.doi.org/10.4103/0976-500X.83282 PMID:21897711 ةيروهجم في ينيعماج بلاط ينب قشنتسُلما نوبركلا ديسكأ لوأ ليلحتب ةيتاذلا ريراقتلا ةنراقم :ينخدتلا ةلاح مييقت ةيملاسلإا ناريإ هدازايلاف دازبه ،بياروتوب-ناماكروت اتيهانأ ،نيمايلس انيتام ،جلوخكن شرآ :ةصلالخا يننخدُلما ددع ديدتح مهلما نم ، َّمَث نمو .لماعلا ءاحنأ عيجم في تايفولاو ةنمزلما ضارملأا نم يرثكل ةيسيئرلا رطلخا لماوع دحأ ينخدتلا برتعُي :ةيفللخا ةيتاذ تانايبتسلاا للاخ نم يننخدُلما لىإ لوصولا ليحتسلما نم حبصأ ،ةعدارلا يربادتلاو مصولا ببسبو .غبتلا ةحفاكمب ةينعلما تاردابلما ذيفنت لبق .غلابلإا .ةيملاسلإا ناريإ ةيروهجم في ينيعمالجا بلاطلل ةيتاذلا ريراقتلاب قشنتسُلما نوبركلا ديسكُأ لوأ تايوتسم ةنراقم لىإ ةساردلا هذه تفده :فادهلأا ،بلاطلا ءلاؤه ينب نمو .نارهط في 2016 ماع في مبه ينعُتسا ًايعماج ًابلاط 60 تمض ةمئلام ةنيع ةيعطقلما ةساردلا هذه تلمش :ثحبلا قرط داتحلااب" صالخا نايبتسلاا مادختساب مهعم تلاباقم تيرجُأو .ًاماع )±15.6( 23.1 مهرمع طسوتم ناكو ًلاجر 30و ةأرما 30 دجوي ناك تطبُر مث ،ينخدتلا ةلاح تنروق دقو .سفنلا ليلتح قيرط نع ىرخأ ةرم مييقتلل اوعضخ مث ،هتمءاوم دعب "ةئرلا ضارمأو لسلا ةحفاكلم ليودلا .نويللما في ءزج 6 دح دنع نوبركلا ديسكأ لوأ تايوتسمب في ،ًايلاح يننخدُلما نم )%31.7( ًاصخش 19 نأ رابتعاب ينخدتلا ةلاح نع غلبُأو ،موي لك )±1.8( 4.7 رئاجسلا كلاهتسا طسوتم غلب :جئاتنلا قشنتسُلما نوبركلا ديسكُأ لوأ تايوتسم ينب ةمهلما تاقلاعلا لىإ لصوتلا مت دقو .)%68.3( ًاصخش 41 تغلب غبتلا اوطاعتي لم نم ةبسن نأ ينح ناك يننخدُلما رتاوت لدعم نإف ،ينخدتلا ةلاحب ةصالخا يربادتلا نع رظنلا ضغبو .)0.05 < ةيلماتحلاا ةميقلا( يننخدُلما يرغو يننخدُلما تاعومجلم .)0.756 = ةيلماتحلاا ةميقلا( يننخدلما يرغ رتاوت لدعم عم ةنراقملل ًلاباق ةياعرلا يمدقلم كلذ حيتيو .يننخدُلما يرغ نع يننخدُلما زييتم في قشنتسلما نوبركلا ديسكُأ لوأ سايق حجن ،ةيتاذلا ريراقتلا رارغ لىعو :تاجاتنتسلاا .هنم ةياقولاو غبتلا يطاعت نع علاقلإاب ةينعلما جمابرلا ةيلاعف ةسارد تاسايسلا يمسارو ةيحصلا 326 Research article EMHJ – Vol. 27 No. 4 – 2021 13. 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