Sequential combination of self-report, breath carbon monoxide, and saliva cotinine to assess smoking status

Evaluating the impact of varying expired carbon monoxide thresholds on smoking relapse identification: insights from the E3 trial on e-cigarette efficacy for smoking cessation

OBJECTIVES

Expired carbon monoxide (ECO) is often used in smoking cessation trials to biochemically validate self-reported smoking status. The optimal ECO threshold to distinguish individuals who smoke from those who do not is debated.

DESIGN

The data from the 'Evaluating the Efficacy of E-Cigarette use for Smoking Cessation (E3) Trial' were used; the E3 trial was a randomised controlled trial that examined e-cigarettes efficacy for smoking cessation.

SETTINGS

Participants were recruited from 17 Canadian sites across 4 provinces.

PARTICIPANTS

This substudy included data from participants who returned for at least one of the clinical visits at week 4 (291), 12 (257) or 24 (218) and provided both self-reported smoking status and ECO measures. Analyses were based on 766 paired measures (ie, self-reported smoking status with corresponding ECO).

RESULTS

The ability of ECO measurements to discriminate between adults who reported smoking and those who reported abstinence varied with the threshold used. ECO thresholds of 6, 7, 8 and 9 parts per million (ppm) yielded the greatest area under the receiver operating characteristic curve (0.84). These thresholds produced sensitivities of 84%, 82%, 78% and 76% and specificities of 84%, 87%, 90% and 91%, respectively. However, at a threshold of 6 ppm, intersecting sensitivity (84%) and specificity (84%) were maximised with respect to each other. Biochemical validation had the highest agreement with self-report at an ECO threshold of 6 ppm (κ=0.57; 95% CI, 0.51 to 0.64).

CONCLUSION

The classification of participants' smoking status depends on the ECO threshold used for biochemical validation. We recommend that future smoking cessation trial investigators analyse and report the impact that varying ECO thresholds has on trial results.

TRIAL REGISTRATION NUMBER

NCT02417467.

Mobile health contingency management for smoking cessation among veterans experiencing homelessness: A comparative effectiveness trial

Tobacco cessation is reduced in U.S. military veterans experiencing homelessness. Mobile contingency management (mCM) is a promising treatment for tobacco use among populations experiencing homelessness, but past CM studies have largely been small, have relied on in-person follow-up, and/or lacked long-term biochemically verified abstinence measures. Veterans who smoked and were experiencing homelessness (N = 127) were randomly assigned to mCM treatment (4 weeks of mCM, 5 weeks of telehealth counseling, and the option of 12 weeks of pharmacotherapy) or VA standard care (3 biweekly group sessions and clinically appropriate pharmacotherapy), and all participants were randomly assigned to a $100 longer-term financial incentive for abstinence at 3-month follow-up. Participants were followed at 3-, 6-, and 12-months post-randomization, with the a priori main outcome designated as biochemically verified prolonged abstinence (with lapses) at 6-month follow-up. At 6-months, participants in the mCM group were significantly more likely to meet criteria for prolonged abstinence (OR = 3.1). Across time points, veterans in the mCM group had twice the odds of prolonged abstinence as those in the standard care group. However, by the 12-month follow-up, there was no statistically significant group difference in abstinence. Cost-effectiveness analysis indicated a modest increase in cost ($1,133) associated with an increase of one quality-adjusted life year saved for the intervention compared to standard care. mCM is a cost-effective approach to smoking cessation among veterans experiencing homelessness. Considering waning potency of this and other tobacco cessation interventions at 12-month follow-up, it is crucial to implement strategies to sustain abstinence for individuals experiencing homelessness.

A Brief Smoking Cessation Advice by Youth Counselors for the Smokers in the Hong Kong Quit to Win Contest 2010: a Cluster Randomized Controlled Trial

Smoking cessation counseling by healthcare professionals is effective, but very few healthcare professionals can deliver these interventions in the busy clinical settings. This study aimed to evaluate the effectiveness of a brief smoking cessation advice delivered by briefly-trained youth counselors at the enrolment of an incentive-based smoking cessation campaign. The study design was a cluster 2-arm randomized controlled trial of 831 Chinese adult smokers who were recruited in public areas to participate in the Hong Kong Quit to Win Contest 2010. The intervention group (n = 441) received a 5-min quitting advice from the youth counselors, who were mainly undergraduate nursing students, and a 12-page self-help smoking cessation booklet at the enrolment, while the control group (n = 390) only received the same booklet. Biochemically confirmed quitters at 6-month follow-up could join a lucky draw that offered HK$10,000 (US$1282) cash prize to three winners and HK$4000 gift vouchers to the other 10 winners. Primary outcome was self-reported smoking abstinence at 6-month follow-up. By intention-to-treat, the intervention group had a non-significantly higher self-reported (18.4 versus 13.8%, OR = 1.40, 95% CI 0.96-2.04, p = 0.08) and validated quit rate (9.1 versus 6.7%, OR = 1.40, 95% CI 0.84-2.33, p = 0.20) than the control group at 6-month follow-up. The analysis with multiple imputation for missing data also found similar results. We concluded that the brief on-site advice by trained youth counselors had a modest effect on smoking cessation, but the effect was not significant. Future studies with larger sample size and results from higher participation of the biochemical validation to confirm the effectiveness are warranted.

Using contingency management procedures to reduce at-risk drinking in heavy drinkers

BACKGROUND

Treatments for alcohol use disorders typically have been abstinence based, but harm reduction approaches that encourage drinkers to alter their drinking behavior to reduce the probability of alcohol-related consequences, have gained in popularity. This study used a contingency management procedure to determine its effectiveness in reducing alcohol consumption among heavy drinkers.

METHODS

Eighty-two nontreatment-seeking heavy drinkers (ages 21 to 54, M = 30.20) who did not meet diagnostic criteria for alcohol dependence participated in the study. The study had 3 phases: (i) an Observation phase (4 weeks) where participants drank normally; (ii) a Contingency Management phase (12 weeks) where participants were paid $50 weekly for not exceeding low levels of alcohol consumption as measured by transdermal alcohol concentrations, <0.03 g/dl; and (iii) a Follow-up phase (12 weeks) where participants (n = 66) returned monthly for 3 months to self-report drinking after the contingencies were removed. Transdermal alcohol monitors were used to verify meeting contingency requirements; all other analyses were conducted on self-reported alcohol use.

RESULTS

On average 42.3% of participants met the contingency criteria and were paid an average of $222 during the Contingency Management phase, with an average $1,998 in total compensation throughout the study. Compared to the Observation phase, the percent of any self-reported drinking days significantly decreased from 59.9 to 40.0% in the Contingency Management and 32.0% in the Follow-up phases. The percent of self-reported heavy drinking days reported also significantly decreased from 42.4% in the Observation phase to 19.7% in the Contingency Management phase, which was accompanied by a significant increase in percent days of self-reported no (from 40.1 to 60.0%) and low-level drinking (from 9.9 to 15.4%). Self-reported reductions in drinking either persisted, or became more pronounced, during the Follow-up phase.

CONCLUSIONS

Contingency management was associated with a reduction in self-reported episodes of heavy drinking among nontreatment-seeking heavy drinkers. These effects persisted even after incentives were removed, indicating the potential utility of contingency management as a therapeutic intervention to reduce harmful patterns of drinking.

Evaluation of toxicant and carcinogen metabolites in the urine of e-cigarette users versus cigarette smokers

INTRODUCTION

Electronic cigarettes (e-cigarettes) are rapidly increasing in popularity but little information is available on their potential toxic or carcinogenic effects.

METHODS

Twenty-eight e-cigarette smokers who had not smoked tobacco cigarettes for at least 2 months provided urine samples which were analyzed by validated methods for a suite of toxicant and carcinogen metabolites including 1-hydroxypyrene (1-HOP), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides (total NNAL), 3-hydroxypropylmercapturic acid (3-HPMA), 2-hydroxypropylmercapturic acid (2-HPMA), 3-hydroxy-1-methylpropylmercapturic acid (HMPMA), S-phenylmercapturic acid (SPMA), nicotine, and cotinine. Levels of these compounds were compared to those found in cigarette smokers from three previous studies.

RESULTS

Levels of 1-HOP, total NNAL, 3-HPMA, 2-HPMA, HMPMA, and SPMA were significantly lower in the urine of e-cigarette users compared to cigarette smokers. Levels of nicotine and cotinine were significantly lower in e-cigarette users compared to cigarette smokers in one study but not in another.

CONCLUSIONS

With respect to the compounds analyzed here, e-cigarettes have a more favorable toxicity profile than tobacco cigarettes.

Quantitative analysis of 3'-hydroxynorcotinine in human urine

INTRODUCTION

Based on previous metabolism studies carried out in patas monkeys, we hypothesized that urinary 3'-hydroxynorcotinine could be a specific biomarker for uptake and metabolism of the carcinogen N'-nitrosonornicotine in people who use tobacco products.

METHODS

We developed a method for quantitation of 3'-hydroxynorcotinine in human urine. [Pyrrolidinone-(13)C4]3'-hydroxynorcotinine was added to urine as an internal standard, the samples were treated with β-glucuronidase, partially purified by solid supported liquid extraction and quantified by liquid chromatography-electrospray ionization-tandem mass spectrometry.

RESULTS

The method was accurate (average accuracy = 102%) and precise (coefficient of variation = 5.6%) in the range of measurement. 3'-Hydroxynorcotinine was detected in 48 urine samples from smokers (mean 393±287 pmol/ml urine) and 12 samples from individuals who had stopped smoking and were using the nicotine patch (mean 658±491 pmol/ml urine), but not in any of 10 samples from nonsmokers.

CONCLUSIONS

Since the amounts of 3'-hydroxynorcotinine found in smokers' urine were approximately 50 times greater than the anticipated daily dose of N'-nitrosonornicotine, we concluded that it is a metabolite of nicotine or one of its metabolites, comprising perhaps 1% of nicotine intake in smokers. Therefore, it would not be suitable as a specific biomarker for uptake and metabolism of N'-nitrosonornicotine. Since 3'-hydroxynorcotinine has never been previously reported as a constituent of human urine, further studies are required to determine its source and mode of formation.

Quantitation of enantiomers of r-7,t-8,9,c-10-tetrahydroxy-7,8,9,10-tetrahydrobenzo[a]-pyrene in human urine: evidence supporting metabolic activation of benzo[a]pyrene via the bay region diol epoxide

Benzo[a]pyrene (BaP), a potent polycyclic aromatic hydrocarbon carcinogen, is widely distributed in the human environment. All humans are exposed to BaP through the diet and contact with the general environment; cigarette smokers have higher exposure. An important pathway of BaP metabolism proceeds through formation of diol epoxides including the 'bay region diol epoxide' 7R,8S-dihydroxy-9S,10R-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene [BaP-(7R,8S)-diol-(9S,10R)-epoxide] and the 'reverse diol epoxide' 9S,10R-dihydroxy-7R,8S-epoxy-7,8,9,10-tetrahydrobenzo [a]pyrene [BaP-(9S,10R)-diol-(7R,8S)-epoxide]. The bay region diol epoxide is considered a major ultimate carcinogen of BaP based on studies in cell culture and laboratory animals, but the available data in humans are less convincing. The bay region diol epoxide and the reverse diol epoxide react with H2O to produce enantiomeric BaP-tetraols that are excreted in the urine. We used chiral stationary-phase high-performance liquid chromatography and gas chromatography-negative ion chemical ionisation-tandem mass spectrometry to quantify these enantiomeric BaP-tetraols in the urine of 25 smokers and 25 non-smokers. The results demonstrated that the BaP-tetraol enantiomer representing the carcinogenic bay region diol epoxide pathway accounted for 68±6% (range 56-81%) of total BaP-tetraol in smokers and 64±6% (range 46-78%) in non-smokers. Levels of the major BaP-tetraol enantiomer decreased by 75% in smokers who quit smoking. These data provide convincing evidence in support of the bay region diol epoxide mechanism of BaP carcinogenesis in humans.

Accuracy of self-reported tobacco use status among hematopoietic SCT patients

Tobacco use is a risk factor for adverse outcomes among Hematopoietic Stem Cell Transplant (HSCT) patients. Accurate identification of tobacco use offers a vital opportunity to treat this risk factor. The current study compared self-reported tobacco use status to serum cotinine levels among HSCT patients at time of pre-transplant evaluation. A total of 444 participants completed both assessments; 44 participants (9.9%) were classified as tobacco users with serum cotinine concentrations > 2ng/Ml versus 29 with self-report. Sensitivity and specificity of self-report were 65.9% and 100%. Positive predictive and negative predictive values were 100% and 96.4%. Comparing tobacco use documented in the medical record with cotinine, sensitivity and specificity were 51.2% and 99.2%. Factors associated with tobacco use were male gender, single relationship status, less education, and younger age. In summary, utilization of serum cotinine assays increased detection of tobacco use cases more than 50% over self-report. Results are discussed in context of translation to care, including clinical and ethical implications, and current tobacco use treatment guidelines. When cotinine assays are not available, self-report of any tobacco use in the year prior to HSCT should trigger brief advice and cessation or relapse prevention counseling.

Provision of smoking cessation support for pregnant women in England: results from an online survey of NHS Stop Smoking Services for Pregnant Women

BACKGROUND

Smoking during pregnancy is a major public health concern and an NHS priority. In 2010, 26% of UK women smoked immediately before or during their pregnancy and 12% smoked continuously. Smoking cessation support is provided through free at the point of use Stop Smoking Services for Pregnant women (SSSP). However, to date, little is known of how these services provide support across England. The aim of this study was to describe the key elements of support provided through English SSSP.

METHODS

SSSP managers were invited to participate in this survey by email. Data were then collected via an online questionnaire; one survey was completed for each SSSP. Up to four reminder emails were sent over a two month period.

RESULTS

86% (121 of 141) of services completed the survey. Responding services were, on average, larger than non-responding services in terms of the number of pregnant women setting quit dates and successfully quitting (p < 0.01). In line with the 2010 NICE guidelines, Stop Smoking in Pregnancy and following Childbirth, one in five SSSP identified pregnant smokers using carbon monoxide (CO) testing and refer via an opt-out pathway. All services offered nicotine replacement therapy (NRT) to pregnant women and 87% of services also offered dual therapy NRT, i.e. combination of a patch and short acting NRT product.. The 2010 NICE guidelines note that services should be flexible and client-centred. Consistent with this, SSSP offer pregnant women a range of support types (median 4) including couple/family, group (open or closed) or one-to-one. These are available in a number of locations (median 5), including in community venues, clinics and women's homes.

CONCLUSIONS

English Stop Smoking Services offer behavioural support and pharmacotherapy to pregnant women motivated to quit smoking. Interventions provided are generally evidence-based and delivered in a variety of both social and health care settings.

Changes in DNA methylation at the aryl hydrocarbon receptor repressor may be a new biomarker for smoking

Background

Smoking is the largest preventable cause of morbidity and mortality in the United States. In previous work, we demonstrated that altered DNA methylation at the aryl hydrocarbon receptor repressor (AHRR) is correlated with self-reported smoking in 19-year-old African Americans with relatively low levels of smoking. However, one limitation of the prior work is that it was based on self-reported data only. Therefore, the relationship of AHRR methylation to smoking in older subjects and to indicators such as serum cotinine levels remains unknown. To address this question, we examined the relationship between genome- wide DNA methylation and smoking status as indicated by serum cotinine levels in a cohort of 22-year-old African American men.

Results

Consistent with prior findings, smoking was associated with significant DNA demethylation at two distinct loci within AHRR (cg05575921 and cg21161138) with the degree of demethylation being greater than that observed in the prior cohort of 19-year-old smoking subjects. Additionally, methylation status at the AHRR residue interrogated by cg05575921 was highly correlated with serum cotinine levels (adjusted R² = 0.42, P < 0.0001).

Conclusions

We conclude that AHRR DNA methylation status is a sensitive marker of smoking history and could serve as a biomarker of smoking that could supplement self-report or existing biomarker measures in clinical or epidemiological analyses of the effects of smoking. In addition, if properly configured as a clinical assay, the determination of AHRR methylation could also be used as a screening tool in efforts to target antismoking interventions to nascent smokers in the early phases of smoking.

Exhaled carbon monoxide and its associations with smoking, indoor household air pollution and chronic respiratory diseases among 512,000 Chinese adults

BACKGROUND

Exhaled carbon monoxide (COex) level is positively associated with tobacco smoking and exposure to smoke from biomass/coal burning. Relatively little is known about its determinants in China despite the population having a high prevalence of smoking and use of biomass/coal.

METHODS

The China Kadoorie Biobank includes 512,000 participants aged 30-79 years recruited from 10 diverse regions. We used linear regression and logistic regression methods to assess the associations of COex level with smoking, exposures to indoor household air pollution and prevalent chronic respiratory conditions among never smokers, both overall and by seasons, regions and smoking status.

RESULTS

The overall COex level (ppm) was much higher in current smokers than in never smokers (men: 11.5 vs 3.7; women: 9.3 vs 3.2). Among current smokers, it was higher among those who smoked more and inhaled more deeply. Among never smokers, mean COex was positively associated with levels of exposures to passive smoking and to biomass/coal burning, especially in rural areas and during winter. The odds ratios (OR) and 95% confidence interval (CI) of air flow obstruction (FEV1/FVC ratio<0.7) for never smokers with COex at 7-14 and ≥14 ppm, compared with those having COex<7, were 1.38 (1.31-1.45) and 1.65 (1.52-1.80), respectively (Ptrend<0.001). Prevalence of other self-reported chronic respiratory conditions was also higher among people with elevated COex (P<0.05).

CONCLUSION

In adult Chinese, COex can be used as a biomarker for assessing current smoking and overall exposure to indoor household air pollution in combination with questionnaires.

Nicotine dependence and biochemical exposure measures in the second trimester of pregnancy

Introduction:

The Heaviness of Smoking Index (HSI) is validated to measure nicotine dependence in nonpregnant smokers, and in these smokers, mean salivary and serum cotinine levels are related by a ratio of 1.25. However, as nicotine metabolism increases during gestation, these findings may differ in pregnancy. We investigated the validity of HSI in pregnancy by comparing this with 3 biochemical measures; in a search for a less-invasive cotinine measure in pregnancy, we also explored the relationship between mean blood and salivary cotinine levels.

Methods:

Cross-sectional analyses using baseline data from the Smoking, Nicotine, and Pregnancy Trial. Participants were 16–46 years old, 12–24 weeks gestation, smoked more than 5 cigarettes per day, and had exhaled carbon monoxide (CO) readings of at least 8 ppm. Linear regression was used to examine correlations between HSI and blood cotinine and salivary cotinine and exhaled CO. Correlation between blood and salivary cotinine was investigated using linear regression through the origin.

Results:

HSI scores were associated with blood cotinine (R² = 0.20, n = 662, p < .001), salivary cotinine (R² = 0.11, n = 967, p < .001), and exhaled CO (R² = 0.13, n = 1,050, p < .001). Salivary and blood cotinine levels, taken simultaneously, were highly correlated (R² = 0.91, n = 628, p < .001) and the saliva:blood level ratio was 1.01 (95% CI 0.99–1.04).

Conclusions:

Correlations between HSI and biochemical measures in pregnancy were comparable with those obtained outside pregnancy, suggesting that HSI has similar validity in pregnant smokers. Salivary and blood cotinine levels are roughly equivalent in pregnant smokers.