Bupropion for smoking cessation in African American light smokers: a randomized controlled trial

Enhancing translation: A need to leverage complex preclinical models of addictive drugs to accelerate substance use treatment options

Preclinical models of addictive drugs have been developed for decades to model aspects of the clinical experience in substance use disorders (SUDs). These include passive exposure as well as volitional intake models across addictive drugs and have been utilized to also measure withdrawal symptomatology and potential neurobehavioral mechanisms underlying relapse to drug seeking or taking. There are a number of Food and Drug Administration (FDA)-approved medications for SUDs, however, many demonstrate low clinical efficacy as well as potential sex differences, and we also note gaps in the continuum of care for certain aspects of clinical experiences in individuals who use drugs. In this review, we provide a comprehensive update on both frequently utilized and novel behavioral models of addiction with a focus on translational value to the clinical experience and highlight the need for preclinical research to follow epidemiological trends in drug use patterns to stay abreast of clinical treatment needs. We then note areas in which models could be improved to enhance the medications development pipeline through efforts to enhance translation of preclinical models. Next, we describe neuroscience efforts that can be leveraged to identify novel biological mechanisms to enhance medications development efforts for SUDs, focusing specifically on advances in brain transcriptomics approaches that can provide comprehensive screening and identification of novel targets. Together, the confluence of this review demonstrates the need for careful selection of behavioral models and methodological parameters that better approximate the clinical experience combined with cutting edge neuroscience techniques to advance the medications development pipeline for SUDs.

Fine-mapping the CYP2A6 regional association with nicotine metabolism among African American smokers

The nicotine metabolite ratio (NMR; 3'hydroxycotinine/cotinine) is a stable biomarker for CYP2A6 enzyme activity and nicotine clearance, with demonstrated clinical utility in personalizing smoking cessation treatment. Common genetic variation in the CYP2A6 region is strongly associated with NMR in smokers. Here, we investigated this regional association in more detail. We evaluated the association of CYP2A6 single-nucleotide polymorphisms (SNPs) and * alleles with NMR among African American smokers (N = 953) from two clinical trials of smoking cessation. Stepwise conditional analysis and Bayesian fine-mapping were undertaken. Putative causal variants were incorporated into an existing African ancestry-specific genetic risk score (GRS) for NMR, and the performance of the updated GRS was evaluated in both African American (n = 953) and European ancestry smokers (n = 933) from these clinical trials. Five independent associations with NMR in the CYP2A6 region were identified using stepwise conditional analysis, including the deletion variant CYP2A6*4 (beta = -0.90, p = 1.55 × 10-11). Six putative causal variants were identified using Bayesian fine-mapping (posterior probability, PP = 0.67), with the top causal configuration including CYP2A6*4, rs116670633, CYP2A6*9, rs28399451, rs8192720, and rs10853742 (PP = 0.09). Incorporating these putative causal variants into an existing ancestry-specific GRS resulted in comparable prediction of NMR within African American smokers, and improved trans-ancestry portability of the GRS to European smokers. Our findings suggest that both * alleles and SNPs underlie the association of the CYP2A6 region with NMR among African American smokers, identify a shortlist of variants that may causally influence nicotine clearance, and suggest that portability of GRSs across populations can be improved through inclusion of putative causal variants.

The efficacy and acceptability of pharmacological monotherapies and e-cigarette on smoking cessation: a systemic review and network meta-analysis

Background and aims

Several pharmacological interventions, such as nicotine replacement therapy (NRT), varenicline, and bupropion, have been approved for clinical use of smoking cessation. E-cigarettes (EC) are increasingly explored by many RCTs for their potentiality in smoking cessation. In addition, some RCTs are attempting to explore new drugs for smoking cessation, such as cytisine. This network meta-analysis (NMA) aims to investigate how these drugs and e-cigarettes compare regarding their efficacy and acceptability.

Materials and methods

This systematic review and NMA searched all clinical studies on smoking cessation using pharmacological monotherapies or e-cigarettes published from January 2011 to May 2022 using MEDLINE, COCHRANE Library, and PsychINFO databases. NRTs were divided into transdermal (TDN) and oronasal nicotine (ONN) by administrative routes, thus 7 network nodes were set up for direct and indirect comparison. Two different indicators measured the efficacy: prevalent and continuous smoking abstinence. The drop-out rates measured the acceptability.

Results

The final 40 clinical studies included in this study comprised 77 study cohorts and 25,889 participants. Varenicline is more effective intervention to assist in smoking cessation during 16-32 weeks follow-up, and is very likely to prompt dropout. Cytisine shows more effectiveness in continuous smoking cessation but may also lead to dropout. E-cigarettes and oronasal nicotine are more effective than no treatment in encouraging prevalent abstinence, but least likely to prompt dropout. Finally, transdermal nicotine delivery is more effective than no treatment in continuous abstinence, with neither significant effect on prevalent abstinence nor dropout rate.

Conclusion

This review suggested and agreed that Varenicline, Cytisine and transdermal nicotine delivery, as smoking cessation intervention, have advantages and disadvantages. However, we had to have reservations about e-cigarettes as a way to quit smoking in adolescents.

Cognitive behavioral therapy versus general health education for smoking cessation: A randomized controlled trial among diverse treatment seekers

OBJECTIVE

Racial and ethnic disparities in smoking cessation persist. This randomized controlled trial compared the efficacy of group cognitive behavioral therapy (CBT) for cessation among African American/Black, Latino/Hispanic, and White adults.

METHOD

African American/Black (39%), Latino/Hispanic (29%), and White (32%) adults (N = 347) were randomly assigned to eight group sessions of CBT or general health education (GHE), both including nicotine patch therapy. Biochemically confirmed 7-day point prevalence abstinence (7-day ppa) was measured at the end-of-therapy, and at 3-, 6-, and 12-month follow-ups. Generalized linear mixed models and logistic regressions tested abstinence rates by condition, stratified by race and ethnicity, and interaction effects.

RESULTS

CBT led to greater abstinence than GHE across 12-months of follow-up (AOR = 1.84, 95% CI [1.59, 2.13]) overall [12-month follow-up: CBT = 54% vs. GHE = 38%] and within racial and ethnic groups [12-months: African American/Black (CBT = 52%, GHE = 29%), Latino/Hispanic (CBT = 57%, GHE = 47%), and White (CBT = 54%, GHE = 41%)]. African American participants were less likely than White participants to quit irrespective of condition, as were persons with lower education and income. Socioeconomic status indicators positively predicted abstinence among racial and ethnic minority participants, but not White participants.

CONCLUSIONS

Group CBT was efficacious compared with GHE. However, cessation patterns suggested that intensive group interventions were less beneficial over the longer term among lower socioeconomic African American and Latino individuals, compared with White participants. Tobacco interventions should target racial and ethnic and socioeconomic differences, via culturally specific approaches and other means. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Varenicline Combined With Oral Nicotine Replacement Therapy and Smartphone-Based Medication Reminders for Smoking Cessation: Feasibility Randomized Controlled Trial

BACKGROUND

Varenicline and oral nicotine replacement therapy (NRT) have each been shown to increase the likelihood of smoking cessation, but their combination has not been studied. In addition, smoking cessation medication adherence is often poor, thus, challenging the ability to evaluate medication efficacy.

OBJECTIVE

This study examined the effects of combined varenicline and oral NRT and smartphone medication reminders on pharmacotherapy adherence and smoking abstinence among adults enrolled in smoking cessation treatment.

METHODS

A 2×2 factorial design was used. Participants (N=34) were randomized to (1) varenicline + oral NRT (VAR+NRT) or varenicline alone (VAR) and (2) smartphone medication reminder messages (REM) or no reminder messages (NREM) over 13 weeks. Participants assigned to VAR+REM received varenicline reminder prompts, and those assigned to VAR+NRT+REM also received reminders to use oral NRT. The other 2 groups (VAR+NREM and VAR+NRT+NREM) did not receive medication reminders. Participants were not blinded to intervention groups. All participants received tobacco cessation counseling. Smartphone assessments of smoking as well as varenicline and NRT use (if applicable) were prompted daily through the first 12 weeks after a scheduled quit date. Descriptive statistics were generated to characterize the relations between medication and reminder group assignments with daily smoking, daily varenicline adherence, and daily quantity of oral NRT used. Participants completed follow-up assessments for 26 weeks after the quit date.

RESULTS

Participants were predominantly White (71%), and half were female (50%). On average, participants were 54.2 (SD 9.4) years of age, they smoked an average of 19.0 (SD 9.0) cigarettes per day and had smoked for 34.6 (SD 12.7) years. Descriptively, participants assigned to VAR+NRT reported more days of smoking abstinence compared to VAR (29.3 vs 26.3 days). Participants assigned to REM reported more days of smoking abstinence than those assigned to NREM (40.5 vs 21.8 days). Participants assigned to REM were adherent to varenicline on more days compared to those assigned to NREM (58.6 vs 40.5 days), and participants assigned to VAR were adherent to varenicline on more days than those assigned to VAR + NRT (50.7 vs 43.3 days). In the subsample of participants assigned to VAR+NRT, participants assigned to REM reported more days where ≥5 pieces of NRT were used than NREM (14.0 vs 7.4 days). Average overall medication adherence (assessed via the Medication Adherence Questionnaire) showed the same pattern as the daily smartphone-based adherence assessments.

CONCLUSIONS

Preliminary findings indicated that smoking cessation interventions may benefit from incorporating medication reminders and combining varenicline with oral NRT, though combining medications may be associated with poorer adherence. Further study is warranted.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03722966; https://classic.clinicaltrials.gov/ct2/show/NCT03722966.

Genomic medicine to reduce tobacco and related disorders: Translation to precision prevention and treatment

Genomic medicine can enhance prevention and treatment. First, we propose that advances in genomics have the potential to enhance assessment of disease risk, improve prognostic predictions, and guide treatment development and application. Clinical implementation of polygenic risk scores (PRSs) has emerged as an area of active research. The pathway from genomic discovery to implementation is an iterative process. Second, we provide examples on how genomic medicine has the potential to solve problems in prevention and treatment using two examples: Lung cancer screening and evidence-based tobacco treatment are both under-utilized and great opportunities for genomic interventions. Third, we discuss the translational process for developing genomic interventions from evidence to implementation by presenting a model to evaluate genomic evidence for clinical implementation, mechanisms of genomic interventions, and patient desire for genomic interventions. Fourth, we present potential challenges in genomic interventions including a great need for evidence in all diverse populations, little evidence on treatment algorithms, challenges in accommodating a dynamic evidence base, and implementation challenges in real world clinical settings. Finally, we conclude that research to identify genomic markers that are associated with smoking cessation success and the efficacy of smoking cessation treatments is needed to empower people of all diverse ancestry. Importantly, genomic data can be used to help identify patients with elevated risk for nicotine addiction, difficulty quitting smoking, favorable response to specific pharmacotherapy, and tobacco-related health problems.

A scoping review of smoking cessation pharmacogenetic studies to advance future research across racial, ethnic, and ancestral populations

Abstinence rates among smokers attempting to quit remain low despite the wide availability and accessibility of pharmacological smoking cessation treatments. In addition, the prevalence of cessation attempts and abstinence differs by individual-level social factors such as race and ethnicity. Clinical treatment of nicotine dependence also continues to be challenged by individual-level variability in effectiveness to promote abstinence. The use of tailored smoking cessation strategies that incorporate information on individual-level social and genetic factors hold promise, although additional pharmacogenomic knowledge is still needed. In particular, genetic variants associated with pharmacological responses to smoking cessation treatment have generally been conducted in populations with participants that self-identify as White race or who are determined to be of European genetic ancestry. These results may not adequately capture the variability across all smokers as a result of understudied differences in allele frequencies across genetic ancestry populations. This suggests that much of the current pharmacogenetic study results for smoking cessation may not apply to all populations. Therefore, clinical application of pharmacogenetic results may exacerbate health inequities by racial and ethnic groups. This scoping review examines the extent to which racial, ethnic, and ancestral groups that experience differences in smoking rates and smoking cessation are represented in the existing body of published pharmacogenetic studies of smoking cessation. We will summarize results by race, ethnicity, and ancestry across pharmacological treatments and study designs. We will also explore current opportunities and challenges in conducting pharmacogenomic research on smoking cessation that encourages greater participant diversity, including practical barriers to clinical utilization of pharmacological smoking cessation treatment and clinical implementation of pharmacogenetic knowledge.

Antidepressants for smoking cessation

BACKGROUND

The pharmacological profiles and mechanisms of antidepressants are varied. However, there are common reasons why they might help people to stop smoking tobacco: nicotine withdrawal can produce short-term low mood that antidepressants may relieve; and some antidepressants may have a specific effect on neural pathways or receptors that underlie nicotine addiction.

OBJECTIVES

To assess the evidence for the efficacy, harms, and tolerability of medications with antidepressant properties in assisting long-term tobacco smoking cessation in people who smoke cigarettes.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group Specialised Register, most recently on 29 April 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in people who smoked, comparing antidepressant medications with placebo or no pharmacological treatment, an alternative pharmacotherapy, or the same medication used differently. We excluded trials with fewer than six months of follow-up from efficacy analyses. We included trials with any follow-up length for our analyses of harms.

DATA COLLECTION AND ANALYSIS

We extracted data and assessed risk of bias using standard Cochrane methods. Our primary outcome measure was smoking cessation after at least six months' follow-up. We used the most rigorous definition of abstinence available in each trial, and biochemically validated rates if available. Our secondary outcomes were harms and tolerance outcomes, including adverse events (AEs), serious adverse events (SAEs), psychiatric AEs, seizures, overdoses, suicide attempts, death by suicide, all-cause mortality, and trial dropouts due to treatment. We carried out meta-analyses where appropriate.

MAIN RESULTS

We included a total of 124 studies (48,832 participants) in this review, with 10 new studies added to this update version. Most studies recruited adults from the community or from smoking cessation clinics; four studies focused on adolescents (with participants between 12 and 21 years old). We judged 34 studies to be at high risk of bias; however, restricting analyses only to studies at low or unclear risk of bias did not change clinical interpretation of the results.  There was high-certainty evidence that bupropion increased smoking cessation rates when compared to placebo or no pharmacological treatment (RR 1.60, 95% CI 1.49 to 1.72; I2 = 16%; 50 studies, 18,577 participants). There was moderate-certainty evidence that a combination of bupropion and varenicline may have resulted in superior quit rates to varenicline alone (RR 1.21, 95% CI 0.95 to 1.55; I2 = 15%; 3 studies, 1057 participants). However, there was insufficient evidence to establish whether a combination of bupropion and nicotine replacement therapy (NRT) resulted in superior quit rates to NRT alone (RR 1.17, 95% CI 0.95 to 1.44; I2 = 43%; 15 studies, 4117 participants; low-certainty evidence). There was moderate-certainty evidence that participants taking bupropion were more likely to report SAEs than those taking placebo or no pharmacological treatment. However, results were imprecise and the CI also encompassed no difference (RR 1.16, 95% CI 0.90 to 1.48; I2 = 0%; 23 studies, 10,958 participants). Results were also imprecise when comparing SAEs between people randomised to a combination of bupropion and NRT versus NRT alone (RR 1.52, 95% CI 0.26 to 8.89; I2 = 0%; 4 studies, 657 participants) and randomised to bupropion plus varenicline versus varenicline alone (RR 1.23, 95% CI 0.63 to 2.42; I2 = 0%; 5 studies, 1268 participants). In both cases, we judged evidence to be of low certainty. There was high-certainty evidence that bupropion resulted in more trial dropouts due to AEs than placebo or no pharmacological treatment (RR 1.44, 95% CI 1.27 to 1.65; I2 = 2%; 25 studies, 12,346 participants). However, there was insufficient evidence that bupropion combined with NRT versus NRT alone (RR 1.67, 95% CI 0.95 to 2.92; I2 = 0%; 3 studies, 737 participants) or bupropion combined with varenicline versus varenicline alone (RR 0.80, 95% CI 0.45 to 1.45; I2 = 0%; 4 studies, 1230 participants) had an impact on the number of dropouts due to treatment. In both cases, imprecision was substantial (we judged the evidence to be of low certainty for both comparisons). Bupropion resulted in inferior smoking cessation rates to varenicline (RR 0.73, 95% CI 0.67 to 0.80; I2 = 0%; 9 studies, 7564 participants), and to combination NRT (RR 0.74, 95% CI 0.55 to 0.98; I2 = 0%; 2 studies; 720 participants). However, there was no clear evidence of a difference in efficacy between bupropion and single-form NRT (RR 1.03, 95% CI 0.93 to 1.13; I2 = 0%; 10 studies, 7613 participants). We also found evidence that nortriptyline aided smoking cessation when compared with placebo (RR 2.03, 95% CI 1.48 to 2.78; I2 = 16%; 6 studies, 975 participants), and some evidence that bupropion resulted in superior quit rates to nortriptyline (RR 1.30, 95% CI 0.93 to 1.82; I2 = 0%; 3 studies, 417 participants), although this result was subject to imprecision. Findings were sparse and inconsistent as to whether antidepressants, primarily bupropion and nortriptyline, had a particular benefit for people with current or previous depression.

AUTHORS' CONCLUSIONS

There is high-certainty evidence that bupropion can aid long-term smoking cessation. However, bupropion may increase SAEs (moderate-certainty evidence when compared to placebo/no pharmacological treatment). There is high-certainty evidence that people taking bupropion are more likely to discontinue treatment compared with people receiving placebo or no pharmacological treatment. Nortriptyline also appears to have a beneficial effect on smoking quit rates relative to placebo, although bupropion may be more effective. Evidence also suggests that bupropion may be as successful as single-form NRT in helping people to quit smoking, but less effective than combination NRT and varenicline. In most cases, a paucity of data made it difficult to draw conclusions regarding harms and tolerability. Further studies investigating the efficacy of bupropion versus placebo are unlikely to change our interpretation of the effect, providing no clear justification for pursuing bupropion for smoking cessation over other licensed smoking cessation treatments; namely, NRT and varenicline. However, it is important that future studies of antidepressants for smoking cessation measure and report on harms and tolerability.

Genotyping, characterization, and imputation of known and novel CYP2A6 structural variants using SNP array data

CYP2A6 metabolically inactivates nicotine. Faster CYP2A6 activity is associated with heavier smoking and higher lung cancer risk. The CYP2A6 gene is polymorphic, including functional structural variants (SV) such as gene deletions (CYP2A6*4), duplications (CYP2A6*1 × 2), and hybrids with the CYP2A7 pseudogene (CYP2A6*12, CYP2A6*34). SVs are challenging to genotype due to their complex genetic architecture. Our aims were to develop a reliable protocol for SV genotyping, functionally phenotype known and novel SVs, and investigate the feasibility of CYP2A6 SV imputation from SNP array data in two ancestry populations. European- (EUR; n = 935) and African- (AFR; n = 964) ancestry individuals from smoking cessation trials were genotyped for SNPs using an Illumina array and for CYP2A6 SVs using Taqman copy number (CN) assays. SV-specific PCR amplification and Sanger sequencing was used to characterize a novel SV. Individuals with SVs were phenotyped using the nicotine metabolite ratio, a biomarker of CYP2A6 activity. SV diplotype and SNP array data were integrated and phased to generate ancestry-specific SV reference panels. Leave-one-out cross-validation was used to investigate the feasibility of CYP2A6 SV imputation. A minimal protocol requiring three Taqman CN assays for CYP2A6 SV genotyping was developed and known SV associations with activity were replicated. The first domain swap CYP2A6-CYP2A7 hybrid SV, CYP2A6*53, was identified, sequenced, and associated with lower CYP2A6 activity. In both EURs and AFRs, most SV alleles were identified using imputation (>70% and >60%, respectively); importantly, false positive rates were <1%. These results confirm that CYP2A6 SV imputation can identify most SV alleles, including a novel SV.

Effect of Varenicline Added to Counseling on Smoking Cessation Among African American Daily Smokers: The Kick It at Swope IV Randomized Clinical Trial

IMPORTANCE

African American smokers have among the highest rates of tobacco-attributable morbidity and mortality in the US, and effective treatment is needed for all smoking levels.

OBJECTIVES

To evaluate the efficacy of varenicline vs placebo among African American adults who are light, moderate, and heavy daily smokers.

DESIGN, SETTING, AND PARTICIPANTS

The Kick It at Swope IV (KIS-IV) trial was a randomized, double-blind, placebo-controlled clinical trial conducted at a federally qualified health center in Kansas City. A total of 500 African American adults who were daily smokers of all smoking levels were enrolled from June 2015 to December 2017; final follow-up was completed in June 2018.

INTERVENTIONS

Participants were provided 6 sessions of culturally relevant individualized counseling and were randomized (in a 3:2 ratio) to receive varenicline (1 mg twice daily; n = 300) or placebo (n = 200) for 12 weeks. Randomization was stratified by sex and smoking level (1-10 cigarettes/d [light smokers] or >10 cigarettes/d [moderate to heavy smokers]).

MAIN OUTCOMES AND MEASURES

The primary outcome was salivary cotinine-verified 7-day point prevalence smoking abstinence at week 26. The secondary outcome was 7-day point prevalence smoking abstinence at week 12, with subgroup analyses for light smokers (1-10 cigarettes/d) and moderate to heavy smokers (>10 cigarettes/d).

RESULTS

Among 500 participants who were randomized and completed the baseline visit (mean age, 52 years; 262 [52%] women; 260 [52%] light smokers; 429 [86%] menthol users), 441 (88%) completed the trial. Treating those lost to follow-up as smokers, participants receiving varenicline were significantly more likely than those receiving placebo to be abstinent at week 26 (15.7% vs 6.5%; difference, 9.2% [95% CI, 3.8%-14.5%]; odds ratio [OR], 2.7 [95% CI, 1.4-5.1]; P = .002). The varenicline group also demonstrated greater abstinence than the placebo group at the end of treatment week 12 (18.7% vs 7.0%; difference, 11.7% [95% CI, 6.0%-17.7%]; OR, 3.0 [95% CI, 1.7-5.6]; P < .001). Smoking abstinence at week 12 was significantly greater for individuals receiving varenicline compared with placebo among light smokers (22.1% vs 8.5%; difference, 13.6% [95% CI, 5.2%-22.0%]; OR, 3.0 [95% CI, 1.4-6.7]; P = .004) and among moderate to heavy smokers (15.1% vs 5.3%; difference, 9.8% [95% CI, 2.4%-17.2%]; OR, 3.1 [95% CI, 1.1-8.6]; P = .02), with no significant smoking level × treatment interaction (P = .96). Medication adverse events were generally comparable between treatment groups, with nausea reported more frequently in the varenicline group (163 of 293 [55.6%]) than the placebo group (90 of 196 [45.9%]).

CONCLUSIONS AND RELEVANCE

Among African American adults who are daily smokers, varenicline added to counseling resulted in a statistically significant improvement in the rates of 7-day point prevalence smoking abstinence at week 26 compared with counseling and placebo. The findings support the use of varenicline in addition to counseling for tobacco use treatment among African American adults who are daily smokers.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02360631.

Does sex alter the relationship between CYP2B6 variation, hydroxybupropion concentration and bupropion-aided smoking cessation in African Americans? A moderated mediation analysis

BACKGROUND AND AIMS

CYP2B6, a genetically variable enzyme, converts bupropion to its active metabolite hydroxybupropion. CYP2B6 activity and bupropion-aided cessation differ between women and men. The aim of this study was to determine whether genetically normal (versus reduced) CYP2B6 activity increases bupropion-aided cessation in African American smokers via higher hydroxybupropion concentration, and whether this differs by sex.

DESIGN AND SETTING

Secondary analysis of a smoking cessation clinical trial (NCT00666978).

PARTICIPANTS/CASES

African American light smokers (≤ 10 cigarettes/day).

INTERVENTIONS

Participants were treated with bupropion for 7 weeks.

MEASUREMENTS

Participants with detectable bupropion and/or hydroxybupropion concentrations were divided into normal (n = 64) and reduced (n = 109) CYP2B6 activity groups based on the presence of decreased-function CYP2B6*6 and CYP2B6*18 alleles. Biochemically verified smoking cessation was assessed at week 3, end of treatment (7 weeks) and follow-up (26 weeks).

FINDINGS

Normal (versus reduced) CYP2B6 activity was associated with increased cessation at week 7, which was mediated by higher hydroxybupropion concentration [odds ratio (OR) = 1.25, 95% confidence interval (CI) = 1.03, 1.78]; this mediation effect persisted at week 26 (OR = 1.23, 95% CI = 1.02, 1.70). The mediation effect was similar in women (n = 116; OR = 1.33, 95% CI = 1.01, 2.30) and men (n = 57; OR = 1.33, 95% CI = 0.92, 3.87). Moreover, sex did not appear to moderate the mediation effect, although this should be tested in a larger sample.

CONCLUSIONS

In African American light smokers with verified early bupropion use, genetically normal CYP2B6 activity appears to be indirectly associated with greater smoking cessation success in a relationship mediated by higher hydroxybupropion concentration. The mediating effect of higher hydroxybupropion concentration on smoking cessation persists beyond the active treatment phase and does not appear to differ by sex.

Use of Contrave, Naltrexone with Bupropion, Bupropion, or Naltrexone and Major Adverse Cardiovascular Events: A Systematic Literature Review

Naltrexone/Bupropion extended release (ER; Contrave) is an extended-release, fixed-dose combination medication of naltrexone (8 mg) and bupropion (90 mg) for patients with obesity or overweight with at least one weight-related comorbidity. Obese and overweight patients with or without comorbidities are at increased cardiovascular (CV) risk. Due to the increased CV risk profile in this patient population, this systematic literature review was conducted to assess human studies reporting major adverse CV events (MACE) and other CV events. A priori eligibility criteria included clinical studies (randomized and observational) published from January 1, 2012, to September 30, 2021, with data comparing users of naltrexone/bupropion ER, naltrexone with bupropion, bupropion without naltrexone, or naltrexone without bupropion versus comparator groups (placebo or other treatments), and with sufficient information to determine the frequency of MACE or other CV adverse events by treatment group. Among 2539 English-language articles identified, 70 articles met the eligibility criteria: seven studies of naltrexone/bupropion ER or naltrexone with bupropion, 32 studies of bupropion, and 31 studies of naltrexone. No studies reported an increased risk of MACE among users of naltrexone/bupropion ER, naltrexone with bupropion, or bupropion or naltrexone individually compared with nonusers. One-half of the available studies (n = 35) reported no (zero) CV events and the other half (n = 35) reported that a non-zero frequency of CV events occurred. Four studies reported data on MACE, including three studies of bupropion and one study of naltrexone/bupropion ER. For composite MACE and its components, the difference in proportions between naltrexone/bupropion ER-, bupropion-, or naltrexone-treated patients compared with active comparators or placebo-treated patients did not exceed 2.5%. In conclusion, the available human evidence does not indicate an increased risk of CV events or MACE following use of naltrexone/bupropion ER, naltrexone with bupropion, or the individual components.

Smoking cessation medicines and e-cigarettes: a systematic review, network meta-analysis and cost-effectiveness analysis

BACKGROUND

Cigarette smoking is one of the leading causes of early death. Varenicline [Champix (UK), Pfizer Europe MA EEIG, Brussels, Belgium; or Chantix (USA), Pfizer Inc., Mission, KS, USA], bupropion (Zyban; GlaxoSmithKline, Brentford, UK) and nicotine replacement therapy are licensed aids for quitting smoking in the UK. Although not licensed, e-cigarettes may also be used in English smoking cessation services. Concerns have been raised about the safety of these medicines and e-cigarettes.

OBJECTIVES

To determine the clinical effectiveness, safety and cost-effectiveness of smoking cessation medicines and e-cigarettes.

DESIGN

Systematic reviews, network meta-analyses and cost-effectiveness analysis informed by the network meta-analysis results.

SETTING

Primary care practices, hospitals, clinics, universities, workplaces, nursing or residential homes.

PARTICIPANTS

Smokers aged ≥ 18 years of all ethnicities using UK-licensed smoking cessation therapies and/or e-cigarettes.

INTERVENTIONS

Varenicline, bupropion and nicotine replacement therapy as monotherapies and in combination treatments at standard, low or high dose, combination nicotine replacement therapy and e-cigarette monotherapies.

MAIN OUTCOME MEASURES

Effectiveness - continuous or sustained abstinence. Safety - serious adverse events, major adverse cardiovascular events and major adverse neuropsychiatric events.

DATA SOURCES

Ten databases, reference lists of relevant research articles and previous reviews. Searches were performed from inception until 16 March 2017 and updated on 19 February 2019.

REVIEW METHODS

Three reviewers screened the search results. Data were extracted and risk of bias was assessed by one reviewer and checked by the other reviewers. Network meta-analyses were conducted for effectiveness and safety outcomes. Cost-effectiveness was evaluated using an amended version of the Benefits of Smoking Cessation on Outcomes model.

RESULTS

Most monotherapies and combination treatments were more effective than placebo at achieving sustained abstinence. Varenicline standard plus nicotine replacement therapy standard (odds ratio 5.75, 95% credible interval 2.27 to 14.90) was ranked first for sustained abstinence, followed by e-cigarette low (odds ratio 3.22, 95% credible interval 0.97 to 12.60), although these estimates have high uncertainty. We found effect modification for counselling and dependence, with a higher proportion of smokers who received counselling achieving sustained abstinence than those who did not receive counselling, and higher odds of sustained abstinence among participants with higher average dependence scores. We found that bupropion standard increased odds of serious adverse events compared with placebo (odds ratio 1.27, 95% credible interval 1.04 to 1.58). There were no differences between interventions in terms of major adverse cardiovascular events. There was evidence of increased odds of major adverse neuropsychiatric events for smokers randomised to varenicline standard compared with those randomised to bupropion standard (odds ratio 1.43, 95% credible interval 1.02 to 2.09). There was a high level of uncertainty about the most cost-effective intervention, although all were cost-effective compared with nicotine replacement therapy low at the £20,000 per quality-adjusted life-year threshold. E-cigarette low appeared to be most cost-effective in the base case, followed by varenicline standard plus nicotine replacement therapy standard. When the impact of major adverse neuropsychiatric events was excluded, varenicline standard plus nicotine replacement therapy standard was most cost-effective, followed by varenicline low plus nicotine replacement therapy standard. When limited to licensed interventions in the UK, nicotine replacement therapy standard was most cost-effective, followed by varenicline standard.

LIMITATIONS

Comparisons between active interventions were informed almost exclusively by indirect evidence. Findings were imprecise because of the small numbers of adverse events identified.

CONCLUSIONS

Combined therapies of medicines are among the most clinically effective, safe and cost-effective treatment options for smokers. Although the combined therapy of nicotine replacement therapy and varenicline at standard doses was the most effective treatment, this is currently unlicensed for use in the UK.

FUTURE WORK

Researchers should examine the use of these treatments alongside counselling and continue investigating the long-term effectiveness and safety of e-cigarettes for smoking cessation compared with active interventions such as nicotine replacement therapy.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016041302.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 59. See the NIHR Journals Library website for further project information.

Interventions for preventing weight gain after smoking cessation

BACKGROUND

Most people who stop smoking gain weight. This can discourage some people from making a quit attempt and risks offsetting some, but not all, of the health advantages of quitting. Interventions to prevent weight gain could improve health outcomes, but there is a concern that they may undermine quitting.

OBJECTIVES

To systematically review the effects of: (1) interventions targeting post-cessation weight gain on weight change and smoking cessation (referred to as 'Part 1') and (2) interventions designed to aid smoking cessation that plausibly affect post-cessation weight gain (referred to as 'Part 2').

SEARCH METHODS

Part 1 - We searched the Cochrane Tobacco Addiction Group's Specialized Register and CENTRAL; latest search 16 October 2020. Part 2 - We searched included studies in the following 'parent' Cochrane reviews: nicotine replacement therapy (NRT), antidepressants, nicotine receptor partial agonists, e-cigarettes, and exercise interventions for smoking cessation published in Issue 10, 2020 of the Cochrane Library. We updated register searches for the review of nicotine receptor partial agonists.

SELECTION CRITERIA

Part 1 - trials of interventions that targeted post-cessation weight gain and had measured weight at any follow-up point or smoking cessation, or both, six or more months after quit day. Part 2 - trials included in the selected parent Cochrane reviews reporting weight change at any time point.

DATA COLLECTION AND ANALYSIS

Screening and data extraction followed standard Cochrane methods. Change in weight was expressed as difference in weight change from baseline to follow-up between trial arms and was reported only in people abstinent from smoking. Abstinence from smoking was expressed as a risk ratio (RR). Where appropriate, we performed meta-analysis using the inverse variance method for weight, and Mantel-Haenszel method for smoking.

MAIN RESULTS

Part 1: We include 37 completed studies; 21 are new to this update. We judged five studies to be at low risk of bias, 17 to be at unclear risk and the remainder at high risk.  An intermittent very low calorie diet (VLCD) comprising full meal replacement provided free of charge and accompanied by intensive dietitian support significantly reduced weight gain at end of treatment compared with education on how to avoid weight gain (mean difference (MD) -3.70 kg, 95% confidence interval (CI) -4.82 to -2.58; 1 study, 121 participants), but there was no evidence of benefit at 12 months (MD -1.30 kg, 95% CI -3.49 to 0.89; 1 study, 62 participants). The VLCD increased the chances of abstinence at 12 months (RR 1.73, 95% CI 1.10 to 2.73; 1 study, 287 participants). However, a second study  found that no-one completed the VLCD intervention or achieved abstinence. Interventions aimed at increasing acceptance of weight gain reported mixed effects at end of treatment, 6 months and 12 months with confidence intervals including both increases and decreases in weight gain compared with no advice or health education. Due to high heterogeneity, we did not combine the data. These interventions increased quit rates at 6 months (RR 1.42, 95% CI 1.03 to 1.96; 4 studies, 619 participants; I² = 21%), but there was no evidence at 12 months (RR 1.25, 95% CI 0.76 to 2.06; 2 studies, 496 participants; I² = 26%). Some pharmacological interventions tested for limiting post-cessation weight gain (PCWG) reduced weight gain at the end of treatment (dexfenfluramine, phenylpropanolamine, naltrexone). The effects of ephedrine and caffeine combined, lorcaserin, and chromium were too imprecise to give useful estimates of treatment effects. There was very low-certainty evidence that personalized weight management support reduced weight gain at end of treatment (MD -1.11 kg, 95% CI -1.93 to -0.29; 3 studies, 121 participants; I² = 0%), but no evidence in the longer-term 12 months (MD -0.44 kg, 95% CI -2.34 to 1.46; 4 studies, 530 participants; I² = 41%). There was low to very low-certainty evidence that detailed weight management education without personalized assessment, planning and feedback did not reduce weight gain and may have reduced smoking cessation rates (12 months: MD -0.21 kg, 95% CI -2.28 to 1.86; 2 studies, 61 participants; I² = 0%; RR for smoking cessation 0.66, 95% CI 0.48 to 0.90; 2 studies, 522 participants; I² = 0%). Part 2: We include 83 completed studies, 27 of which are new to this update. There was low certainty that exercise interventions led to minimal or no weight reduction compared with standard care at end of treatment (MD -0.25 kg, 95% CI -0.78 to 0.29; 4 studies, 404 participants; I² = 0%). However, weight was reduced at 12 months (MD -2.07 kg, 95% CI -3.78 to -0.36; 3 studies, 182 participants; I² = 0%). Both bupropion and fluoxetine limited weight gain at end of treatment (bupropion MD -1.01 kg, 95% CI -1.35 to -0.67; 10 studies, 1098 participants; I² = 3%); (fluoxetine MD -1.01 kg, 95% CI -1.49 to -0.53; 2 studies, 144 participants; I² = 38%; low- and very low-certainty evidence, respectively). There was no evidence of benefit at 12 months for bupropion, but estimates were imprecise (bupropion MD -0.26 kg, 95% CI -1.31 to 0.78; 7 studies, 471 participants; I² = 0%). No studies of fluoxetine provided data at 12 months. There was moderate-certainty that NRT reduced weight at end of treatment (MD -0.52 kg, 95% CI -0.99 to -0.05; 21 studies, 2784 participants; I² = 81%) and moderate-certainty that the effect may be similar at 12 months (MD -0.37 kg, 95% CI -0.86 to 0.11; 17 studies, 1463 participants; I² = 0%), although the estimates are too imprecise to assess long-term benefit. There was mixed evidence of the effect of varenicline on weight, with high-certainty evidence that weight change was very modestly lower at the end of treatment (MD -0.23 kg, 95% CI -0.53 to 0.06; 14 studies, 2566 participants; I² = 32%); a low-certainty estimate gave an imprecise estimate of higher weight at 12 months (MD 1.05 kg, 95% CI -0.58 to 2.69; 3 studies, 237 participants; I² = 0%).

AUTHORS' CONCLUSIONS

Overall, there is no intervention for which there is moderate certainty of a clinically useful effect on long-term weight gain. There is also no moderate- or high-certainty evidence that interventions designed to limit weight gain reduce the chances of people achieving abstinence from smoking.

Analyses of nicotine metabolism biomarker genetics stratified by sex in African and European Americans

Nicotine is inactivated by the polymorphic CYP2A6 enzyme to cotinine and then to 3′hydroxycotinine. The Nicotine Metabolite Ratio (NMR; 3′hydroxycotinine/cotinine) is a heritable nicotine metabolism biomarker, varies with sex and ancestry, and influences smoking cessation and disease risk. We conducted sex-stratified genome-wide association studies of the NMR in European American (EA) and African American (AA) smokers (NCT01314001, NCT00666978). In EA females (n = 389) and males (n = 541), one significant (P < 5e−8) chromosome 19 locus was found (top variant: rs56113850, CYP2A6 (intronic), for C vs. T: females: beta = 0.67, P = 7.5e−22, 21.8% variation explained; males: beta = 0.75, P = 1.2e−37, 26.1% variation explained). In AA females (n = 503) and males (n = 352), the top variant was found on chromosome 19 but differed by sex (females: rs11878604, CYP2A6 (~ 16 kb 3′), for C vs. T: beta = − 0.71, P = 6.6e−26, 16.2% variation explained; males: rs3865454, CYP2A6 (~ 7 kb 3′), for G vs. T: beta = 0.64, P = 1.9e−19, 18.9% variation explained). In AA females, a significant region was found on chromosome 12 (top variant: rs12425845: P = 5.0e−9, TMEM132C (~ 1 Mb 5′), 6.1% variation explained) which was not significant in AA males. In AA males, significant regions were found on chromosomes 6 (top variant: rs9379805: P = 4.8e−9, SLC17A2 (~ 8 kb 5′), 8.0% variation explained) and 16 (top variant: rs77368288: P = 3.5e−8, ZNF469 (~ 92 kb 5′), 7.1% variation explained) which were not significant in AA females. Further investigation of these associations outside of chromosome 19 is required, as they did not replicate. Understanding how sex and ancestry influence nicotine metabolism genetics may improve personalized approaches for smoking cessation and risk prediction for tobacco-related diseases.

Nicotine metabolite ratio: Comparison of the three urinary versions to the plasma version and nicotine clearance in three clinical studies

BACKGROUND

Variation in CYP2A6 activity influences tobacco smoking behaviors and smoking-related health outcomes. Plasma Nicotine Metabolite Ratio (NMR) is a robust phenotypic biomarker of CYP2A6 activity and nicotine clearance. In urine, the NMR has been calculated as a ratio of free trans-3'-hydroxycotinine to free cotinine (NMR_F/F), total trans-3'-hydroxycotinine to free cotinine (NMR_T/F), or total trans-3'-hydroxycotinine to total cotinine (NMR_T/T). We evaluated these three urinary NMR versions relative to plasma NMR and nicotine clearance and elucidated mechanisms of discrepancies among them.

METHODS

Baseline plasma and urine biomarker data were available from two smoking cessation clinical trials and one nicotine pharmacokinetic study (total N = 768). NMRs were compared using Pearson correlations, linear regressions and ANOVA analyses. UGT2B10 and UGT2B17 were genotyped.

RESULTS

Urinary NMR_T/F was the most highly related to plasma NMR (R² = 0.70, P <2.2e-16) followed by NMR_F/F (R² = 0.68, P <2.2e-16), while NMR_T/T was less strongly related (R² = 0.60, P <2.2e-16); consistent across study, ethnicity, sex, heaviness of smoking, and analyte analysis. Controlling for cotinine glucuronidation, as a phenotype or UGT2B10 genotype, corrected the NMR_T/T discordance with plasma NMR (P_anova<0.001). Similar findings were obtained for relationships of nicotine clearance with plasma NMR > urinary NMR_T/F > NMR_F/F > NMR_T/T (R² = 0.41 > 0.37 > 0.35 > 0.25 respectively).

CONCLUSION

Urinary NMR_T/F followed by NMR_F/F are the best urinary alternatives to plasma NMR or nicotine clearance. NMR_T/T has the least utility as it is influenced substantially by variation in cotinine glucuronidation.

IMPACT

This work highlighted the variation in urinary NMRs, and identified mechanisms for disparities among them, which facilitates their use in predicting smoking-related outcomes.

Cue-based treatment for light smokers: A proof of concept pilot

INTRODUCTION

Light smoking (smoking ≤ 10 cigarettes per day or on some days) has become increasingly prevalent in the US and increases morbidity and mortality. Many light smokers do not experience significant nicotine withdrawal but instead smoke in response to cues. Minimal evidence exists supporting interventions to help light smokers quit smoking.

METHODS

We present results from a proof-of-concept pilot study designed to evaluate the feasibility and acceptability of a cue-based smoking cessation intervention targeted to light daily and intermittent smokers. Participants were randomized to one of two arms: Arm 1) standard smoking cessation treatment or Arm 2) standard smoking cessation treatment + enhanced cue-based treatment that included interactive texting to extend cue exposure treatment to real-world settings and cue management counseling.Outcomes included feasibility (number of participants who were recruited and who completed the intervention), acceptability (intervention ratings), and preliminary efficacy (7-day point prevalence abstinence).

RESULTS

We randomized 24 English and Spanish-speaking light smokers, 13 to the treatment arm and 11 to the control arm. Across both arms, 77% attended all counseling sessions, 90% rated these sessions as very useful and 100% said that they would recommend the intervention to a friend. 15% in the treatment arm had biochemically-validated smoking abstinence compared to 0% in the standard counseling arm.

CONCLUSIONS

Results from this proof-of-concept study demonstrated that a cue-based intervention is feasible and acceptable among light smokers and suggests the need for a fully powered study to assess this approach.

TRIAL REGISTRATION

This study is registered at www.clinicaltrials.gov NCT03416621.

Comparative efficacy and safety of pharmacological interventions for smoking cessation in healthy adults: A network meta-analysis

Smoking is the leading cause of morbidity and mortality in different non-communicable diseases, and cessation leads to immense health benefits. The present network meta-analysis has been conducted to evaluate and compare the effects of available pharmacological interventions for smoking cessation in adults. A standard meta-analysis protocol was developed and after performing a comprehensive literature search on MEDLINE/PubMed, Cochrane databases, and International Clinical Trials Registry Platform, reviewers extracted data from 97 randomized controlled trials. PRISMA guidelines were followed in data extraction, analysis and reporting of findings. Random effects Bayesian network meta-analysis was done to pool the effects across the interventions. Network graph was built, and for closed triangles in the network graph, node splitting analysis was performed. The primary outcome measure was self-reported biochemically verified smoking abstinence at six months. The number of participants achieving continuous abstinence was reported. Data for the number of participants reporting at least one adverse event was also extracted, if available. Combination of nicotine receptor agonist and nicotine replacement therapy had a significant odd of 4.4 (95%CrI:2.2-8.7), bupropion and nicotine receptor agonist 4.0 (95%CrI:2.1-7.7), bupropion and nicotine replacement therapy 3.8 (95%CrI:2.3-6.2), combination nicotine replacement therapy has an odd of 2.6 (95%CrI:1.8-3.8), and nicotine receptor agonist had a significant odd of 2.7 (95%CrI:2.3-3.2) when compared to placebo (moderate quality of evidence) for continuous abstinence at 6 months. When compared with behavioural therapy, the odds ratio of interventions was not statistically significant. Combination of nicotine receptor agonist and nicotine replacement therapy has the highest probability of being the best treatment for abstinence from smoking.

Placebo-controlled trial of bupropion for smoking cessation in pregnant women

BACKGROUND

Although a relatively small proportion of women who become pregnant continue to smoke cigarettes, no smoking cessation medication has been shown to be effective for this subgroup of smokers. Bupropion, a nonnicotine-based medication, is approved for the promotion of smoking cessation in nonpregnant individuals. We chose to study it in pregnant smokers because, although pregnancy increases nicotine metabolism, it does not affect the metabolism of bupropion.

OBJECTIVE

We evaluated the efficacy and safety of sustained-release bupropion for smoking cessation among pregnant women.

STUDY DESIGN

We conducted a multiple site, placebo-controlled, randomized clinical trial of bupropion for tobacco use among pregnant women (N=129) (clinical trial number NCT02188459). We enrolled women during the second trimester and randomly assigned them to receive 10 weeks of treatment with either bupropion or placebo, accompanied by a total of 6 smoking cessation counseling sessions (4 during treatment and 2 postpartum). The primary outcome was 7-day point prevalence smoking abstinence, confirmed with breath carbon monoxide measurements, at the end of treatment (week 10) and at week 24. Group differences were assessed as a binary abstinence outcome using a repeated measure generalized estimating equations model with a logit link. Prolonged abstinence and smoking rates were secondary outcomes. Safety measures included maternal treatment-related adverse events, gestational age, the rate of overall and spontaneous preterm births and infant birthweight and size for gestational age, head circumference, and 5-minute Apgar scores.

RESULTS

There were no significant differences in the safety measures across the treatment arms and bupropion was not efficacious in promoting smoking cessation at the end of treatment (7-day point prevalence quit rates: bupropion, 11.0%; placebo, 18.5%) or week 24 (7-day point prevalence quit rates: bupropion, 9.4%; placebo, 21.5%) (P>.05). African American women and women with a lower severity of nicotine dependence had significantly higher quit rates overall and women with an opioid use disorder who were being treated with opioid agonist therapy had significantly lower quit rates overall, irrespective of the treatment group (all P values <.05).

CONCLUSION

Although bupropion use was not associated with an elevated risk for pregnancy complications when initiated in the second trimester, it did not increase the likelihood of smoking cessation in this cohort of pregnant women. Because smoking is the major preventable source of poor pregnancy outcomes and psychosocial interventions have only modest beneficial effects, additional studies are needed to identify safe and efficacious smoking cessation medications for pregnant women who continue to smoke.

Assessment of Racial Differences in Pharmacotherapy Efficacy for Smoking Cessation: Secondary Analysis of the EAGLES Randomized Clinical Trial

Importance

Understanding Black vs White differences in pharmacotherapy efficacy and the underlying reasons is critically important to reducing tobacco-related health disparities.

Objective

To compare pharmacotherapy efficacy and examine variables to explain Black vs White differences in smoking abstinence.

Design, Setting, and Participants

This study is a secondary analysis of the Evaluating Adverse Events in a Global Smoking Cessation Study (EAGLES) double-blind, placebo-controlled, randomized clinical trial, which took place at clinical trial centers, academic centers, and outpatient clinics in 29 states in the US. US Black and White smokers who smoked 10 or more cigarettes per day with and without psychiatric comorbidity were enrolled between November 2011 and January 2015. Data analysis was performed from July 2019 to January 2020.

Interventions

Participants were randomized (1:1:1:1) in a double-blind, triple-dummy, placebo- and active-controlled (nicotine patch) trial of varenicline and bupropion for 12 weeks with follow-up through week 24.

Main Outcomes and Measures

Biochemically verified continuous cigarette abstinence rate (CAR) from weeks 9 to 24. Baseline, postbaseline treatment, and safety characteristics were examined as variables to explain race differences in abstinence.

Results

Of the 1065 Black smokers enrolled, 255 were randomized to receive varenicline, 259 received bupropion, 286 received nicotine replacement therapy (NRT [ie, nicotine patch]), and 265 received placebo. Among the 3044 White smokers enrolled, 778 were randomized to receive varenicline, 769 received bupropion, 738 received NRT, and 759 received placebo. Participants were predominantly female (614 Black [57.7%] and 1786 White [58.7%] women) and heavy smokers (mean [SD] cigarettes per day, 18.2 [7.9] for Black and 20.0 [7.5] for White smokers), with a mean (SD) age of 47.2 (11.2) years for Black and 46.5 (12.7) years for White participants. Treatment and race were associated with CAR for weeks 9 to 24. The CAR was 4.9% lower for Black vs White participants (odds ratio [OR], 0.53; 95% CI, 0.41-0.69; P < .001); differences were found across all treatments. Pooling psychiatric and nonpsychiatric cohorts, varenicline (OR, 2.63; 95% CI, 1.90-3.63; P < .001), bupropion (OR, 1.75; 95% CI, 1.25-2.46; P = .001), and NRT (OR, 1.52; 95% CI, 1.07-2.16; P = .02) had greater efficacy than placebo for White participants. Only varenicline (OR, 2.63; 95% CI, 1.26-5.48; P = .01) had greater efficacy than placebo for Black participants. Baseline, postbaseline, and safety characteristics differed by race, but these variables did not eliminate the association of race with CAR. Black participants had 49% reduced odds of CAR for weeks 9 to 24 compared with White participants in the adjusted model (OR, 0.51; 95% CI, 0.39-0.66; P < .001).

Conclusions and Relevance

Black and White smokers achieved the highest rate of abstinence while taking varenicline, suggesting that it is the best first-line therapy for these groups. However, Black smokers were less responsive to all therapies, including placebo. Understanding variables (eg, socioeconomic or biological) beyond those may lead to improved treatment outcomes for Black smokers.

Trial Registration

ClinicalTrials.gov Identifier: NCT01456936.

Smoking Cessation Treatment for Parents Who Are Light or Very Light Smokers in the Pediatric Setting

BACKGROUND

The percentage of US smokers who smoke <10 cigarettes per day has increased, yet it is not known how often light parental smokers are offered and accept cessation assistance in pediatric offices.

METHODS

A secondary analysis of parent interview data collected April to October 2017 at 10 pediatric practices participating in a cluster-randomized controlled trial of the Clinical Effort Against Secondhand Smoke Exposure (CEASE) intervention.

RESULTS

Forty percent of 725 usual care control (UCC) group smokers smoked lightly (<10 cigarettes per day); of these 58% smoked very lightly (<5 per day). Compared to heavier smokers in UCC practices, light and very light smokers in UCC practices were more likely to have made a recent quit attempt (P < .001), yet less likely to have used cessation medication (P = .001). In intervention practices, compared to heavier smokers, light (P = .04) and very light (P < .01) smokers were less likely to be asked if they smoke and very light smokers were less likely to be advised to quit (P = .02) and to receive a nicotine replacement therapy (NRT) prescription (P < .01). However, light smokers (P < .001), very light smokers (P < .001), and light smokers who use e-cigarettes (P = .01) were more likely to receive assistance (NRT or quitline enrollment) in intervention versus UCC practices.

CONCLUSIONS

The CEASE intervention increased assistance to light and very light smokers, yet heavier smokers received more assistance than light smokers. Improving cessation interventions for light and very light smokers is warranted.

Transferability of Ancestry-Specific and Cross-Ancestry CYP2A6 Activity Genetic Risk Scores in African and European Populations

The Nicotine Metabolite Ratio (NMR; 3-hydroxycotinine/cotinine), a highly heritable index of nicotine metabolic inactivation by the CYP2A6 enzyme, is associated with numerous smoking behaviors and diseases, as well as unique cessation outcomes. However, the NMR cannot be measured in nonsmokers, former smokers, or intermittent smokers, for example, in evaluating tobacco-related disease risk. Traditional pharmacogenetic groupings based on CYP2A6 * alleles capture a modest portion of NMR variation. We previously created a CYP2A6 weighted genetic risk score (wGRS) for European (EUR)-ancestry populations by incorporating independent signals from genome-wide association studies to capture a larger proportion of NMR variation. However, CYP2A6 genetic architecture is unique to ancestral populations. In this study, we developed and replicated an African-ancestry (AFR) wGRS, which captured 30-35% of the variation in NMR. We demonstrated model robustness against known environmental sources of NMR variation. Furthermore, despite the vast diversity within AFR populations, we showed that the AFR wGRS was consistent between different US geographical regions and unaltered by fine AFR population substructure. The AFR and EUR wGRSs can distinguish slow from normal metabolizers in their respective populations, and were able to reflect unique smoking cessation pharmacotherapy outcomes previously observed for the NMR. Additionally, we evaluated the utility of a cross-ancestry wGRS, and the capacity of EUR, AFR, and cross-ancestry wGRSs to predict the NMR within stratified or admixed AFR-EUR populations. Overall, our findings establish the clinical benefit of applying ancestry-specific wGRSs, demonstrating superiority of the AFR wGRS in AFRs.

Counseling alone or in combination with nicotine replacement therapy for treatment of black non-daily smokers: a randomized trial

BACKGROUND AND AIMS

One-third of US tobacco users are non-daily smokers (NDS). Black NDS have strikingly high levels of nicotine and carcinogen exposure. No smoking cessation studies have been conducted with this high-risk group. This study compared the effectiveness in black NDS of smoking cessation counseling alone or in combination with the participant's choice of nicotine replacement therapy.

DESIGN

Two-arm parallel-group individually randomized clinical trial (allocation ratio of 2 : 1 intervention to control) SETTING: Academic medical and federally qualified health centers in three US cities.

PARTICIPANTS

Non-Hispanic black adult NDS receiving counseling with nicotine replacement therapy (C + NRT, n = 185) or counseling alone (C, n = 93).

INTERVENTIONS

Twelve weeks of in-person and telephone smoking cessation counseling in combination with nicotine replacement therapy (NRT; C + NRT) or counseling alone (C). All participants received five sessions of counseling; those randomized to C + NRT received their choice of nicotine gum, patch and/or lozenge after a 9-day product trial period. The target quit day was set at 2 weeks post-baseline for both groups.

MEASUREMENTS

Primary outcome was biochemically verified 30-day abstinence at week 12. Secondary outcomes were change in nicotine and carcinogen exposure [4-(methynitrosamino)-1-(3) pyridyle-1-butanol; NNAL] and tobacco consumption patterns.

FINDINGS

Abstinence was 11.4% in C + NRT and 8.6% in C [odds ratio (OR) = 1.4, 95% confidence interval (CI) = 0.6, 3.2, P = 0.48]. Both groups experienced significant reduction in NNAL (C + NRT: 53% reduction, C: 50% reduction, within-group P < 0.0001) but non-significant changes in cotinine (P = 0.69). C + NRT reported more days abstinent (P < 0.001) and fewer total cigarettes (P = 0.002) compared with C. There was no evidence of compensation with other tobacco products.

CONCLUSIONS

Among black non-daily smokers in the United States, there was no difference in abstinence between nicotine replacement therapy (NRT) and counseling alone. NRT led to greater increase in days abstinent and reduction in cigarettes, with no evidence of compensation from other sources of nicotine.

Factors That Explain Differences in Abstinence Between Black and White Smokers: A Prospective Intervention Study

BACKGROUND

Black-white differences in smoking abstinence are not well understood. This trial sought to confirm previously reported differences in quitting between blacks and whites and to identify factors underlying this difference.

METHODS

During enrollment, 224 black and 225 white low-income smokers were stratified on race and within race on age and sex to ensure balance on these factors known to impact abstinence. The intervention included varenicline for 12 weeks and six guideline-based smoking cessation counseling sessions. The primary endpoint was cotinine-verified 7-day point prevalence smoking abstinence at week 26. A priori socioeconomic, smoking, treatment process (eg, treatment utilization, side effects, withdrawal relief), psychosocial, and biological factors were assessed to investigate race differences in abstinence. Unadjusted odds ratios (OR) were used to compare abstinence between blacks and whites. Adjusted odds ratios from logistic regression models were used to examine predictors of abstinence. All statistical tests were two-sided.

RESULTS

Blacks were less likely to achieve abstinence at week 26 (14.3% vs 24.4%, OR = 0.51, 95% confidence interval [CI] = 0.32 to 0.83, P = .007). Utilizing best subsets logistic regression, five factors associated with race jointly predicted abstinence: home ownership (yes/no, OR = 3.03, 95% CI = 1.72 to 5.35, P < .001), study visits completed (range = 0-6, OR = 2.81, 95% CI = 1.88 to 4.20, P < .001), income (household member/$1000, OR = 1.03, 95% CI = 1.01 to 1.06, P = .02), plasma cotinine (per 1 ng/mL, OR = 0.997, 95% CI = 0.994 to 0.999, P = .002), and neighborhood problems (range = 10-30, OR = 0.88, 95% CI = 0.81 to 0.96, P = .003).

CONCLUSIONS

The race difference in abstinence was fully explained by lack of home ownership, lower income, greater neighborhood problems, higher baseline cotinine, and higher visit completion, which were disproportionately represented among blacks. Findings illuminate factors that make it harder for blacks in the United States to quit smoking relative to whites and provide important areas for future studies to reduce tobacco-related health disparities.

Enhancing nicotine replacement therapy usage and adherence through a mobile intervention: Secondary data analysis of a single-arm feasibility study in Mexico

INSTRODUCTION

Nicotine Replacement Therapy (NRT) is an effective treatment for smoking cessation. However, medication usage and adherence remain a challenge that contributes to low smoking cessation rates. In Mexico, 8 in 10 smokers are interested in quitting. However, only 6% of Mexican smokers use medication for smoking cessation. The objective of this study is to assess the feasibility and acceptability of a mobile health (mHealth) intervention to increase usage and adherence of NRT in Mexico.

METHODS

The study involves a secondary data analysis. Forty smokers were recruited to participate in a single-arm pilot study. Participants received an mHealth intervention that uses tablet-based decision support software to drive a 12-week text messaging smoking cessation program and pharmacotherapy support. The intervention allows two-way interactivity text messaging between participants and a tobacco treatment specialist. NRT was offered to participants in accordance with practice guidelines in Mexico. Outcome measures included utilization of NRT, text messaging interactivity with the program, and biochemically verified abstinence at 12 weeks.

RESULTS

Thirty smokers met the criteria for use of NRT. Average age of participants was 38.1 years (SD=10.7), and they were primarily male (56.7%) with at least an undergraduate degree (60%). All participants requested NRT at baseline, and 60% requested a refill at week 4. During the 12-week intervention period, participants sent 620 messages to the program (mean=20.6, SD=18.34) of which 79 messages (12.7%) were related to NRT. Three themes were identified in the messages related to NRT: enthusiasm, instructions, and side effects. At 12 weeks, 40% of participants reported using NRT <75% of the days. Finally, 30% of participants (9/30) were biochemically verified abstinent using intention-to-treat analysis at 12 weeks.

CONCLUSIONS

An mHealth intervention appears to offer a promising strategy to increase usage and adherence of NRT in Mexico. Additional testing as a formal randomized clinical trial appears warranted.

Antidepressants for smoking cessation

BACKGROUND

Whilst the pharmacological profiles and mechanisms of antidepressants are varied, there are common reasons why they might help people to stop smoking tobacco. Firstly, nicotine withdrawal may produce depressive symptoms and antidepressants may relieve these. Additionally, some antidepressants may have a specific effect on neural pathways or receptors that underlie nicotine addiction.

OBJECTIVES

To assess the evidence for the efficacy, safety and tolerability of medications with antidepressant properties in assisting long-term tobacco smoking cessation in people who smoke cigarettes.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Specialized Register, which includes reports of trials indexed in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO, clinicaltrials.gov, the ICTRP, and other reviews and meeting abstracts, in May 2019.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that recruited smokers, and compared antidepressant medications with placebo or no treatment, an alternative pharmacotherapy, or the same medication used in a different way. We excluded trials with less than six months follow-up from efficacy analyses. We included trials with any follow-up length in safety analyses.

DATA COLLECTION AND ANALYSIS

We extracted data and assessed risk of bias using standard Cochrane methods. We also used GRADE to assess the certainty of the evidence. The primary outcome measure was smoking cessation after at least six months follow-up, expressed as a risk ratio (RR) and 95% confidence intervals (CIs). We used the most rigorous definition of abstinence available in each trial, and biochemically validated rates if available. Where appropriate, we performed meta-analysis using a fixed-effect model. Similarly, we presented incidence of safety and tolerance outcomes, including adverse events (AEs), serious adverse events (SAEs), psychiatric AEs, seizures, overdoses, suicide attempts, death by suicide, all-cause mortality, and trial dropout due to drug, as RRs (95% CIs).

MAIN RESULTS

We included 115 studies (33 new to this update) in this review; most recruited adult participants from the community or from smoking cessation clinics. We judged 28 of the studies to be at high risk of bias; however, restricting analyses only to studies at low or unclear risk did not change clinical interpretation of the results. There was high-certainty evidence that bupropion increased long-term smoking cessation rates (RR 1.64, 95% CI 1.52 to 1.77; I2 = 15%; 45 studies, 17,866 participants). There was insufficient evidence to establish whether participants taking bupropion were more likely to report SAEs compared to those taking placebo. Results were imprecise and CIs encompassed no difference (RR 1.16, 95% CI 0.90 to 1.48; I2 = 0%; 21 studies, 10,625 participants; moderate-certainty evidence, downgraded one level due to imprecision). We found high-certainty evidence that use of bupropion resulted in more trial dropouts due to adverse events of the drug than placebo (RR 1.37, 95% CI 1.21 to 1.56; I2 = 19%; 25 studies, 12,340 participants). Participants randomized to bupropion were also more likely to report psychiatric AEs compared with those randomized to placebo (RR 1.25, 95% CI 1.15 to 1.37; I2 = 15%; 6 studies, 4439 participants). We also looked at the safety and efficacy of bupropion when combined with other non-antidepressant smoking cessation therapies. There was insufficient evidence to establish whether combination bupropion and nicotine replacement therapy (NRT) resulted in superior quit rates to NRT alone (RR 1.19, 95% CI 0.94 to 1.51; I2 = 52%; 12 studies, 3487 participants), or whether combination bupropion and varenicline resulted in superior quit rates to varenicline alone (RR 1.21, 95% CI 0.95 to 1.55; I2 = 15%; 3 studies, 1057 participants). We judged the certainty of evidence to be low and moderate, respectively; in both cases due to imprecision, and also due to inconsistency in the former. Safety data were sparse for these comparisons, making it difficult to draw clear conclusions. A meta-analysis of six studies provided evidence that bupropion resulted in inferior smoking cessation rates to varenicline (RR 0.71, 95% CI 0.64 to 0.79; I2 = 0%; 6 studies, 6286 participants), whilst there was no evidence of a difference in efficacy between bupropion and NRT (RR 0.99, 95% CI 0.91 to 1.09; I2 = 18%; 10 studies, 8230 participants). We also found some evidence that nortriptyline aided smoking cessation when compared with placebo (RR 2.03, 95% CI 1.48 to 2.78; I2 = 16%; 6 studies, 975 participants), whilst there was insufficient evidence to determine whether bupropion or nortriptyline were more effective when compared with one another (RR 1.30 (favouring bupropion), 95% CI 0.93 to 1.82; I2 = 0%; 3 studies, 417 participants). There was no evidence that any of the other antidepressants tested (including St John's Wort, selective serotonin reuptake inhibitors (SSRIs), monoamine oxidase inhibitors (MAOIs)) had a beneficial effect on smoking cessation. Findings were sparse and inconsistent as to whether antidepressants, primarily bupropion and nortriptyline, had a particular benefit for people with current or previous depression.

AUTHORS' CONCLUSIONS

There is high-certainty evidence that bupropion can aid long-term smoking cessation. However, bupropion also increases the number of adverse events, including psychiatric AEs, and there is high-certainty evidence that people taking bupropion are more likely to discontinue treatment compared with placebo. However, there is no clear evidence to suggest whether people taking bupropion experience more or fewer SAEs than those taking placebo (moderate certainty). Nortriptyline also appears to have a beneficial effect on smoking quit rates relative to placebo. Evidence suggests that bupropion may be as successful as NRT and nortriptyline in helping people to quit smoking, but that it is less effective than varenicline. There is insufficient evidence to determine whether the other antidepressants tested, such as SSRIs, aid smoking cessation, and when looking at safety and tolerance outcomes, in most cases, paucity of data made it difficult to draw conclusions. Due to the high-certainty evidence, further studies investigating the efficacy of bupropion versus placebo are unlikely to change our interpretation of the effect, providing no clear justification for pursuing bupropion for smoking cessation over front-line smoking cessation aids already available. However, it is important that where studies of antidepressants for smoking cessation are carried out they measure and report safety and tolerability clearly.

Helen G, Nardone N, Cox LS, Jacob P. Urine Metabolites for Estimating Daily Intake of Nicotine From Cigarette Smoking

INTRODUCTION

Accurate measurement of nicotine exposure from cigarette smoke is important in studying disease risk and level of dependence. Urine total nicotine equivalents, the molar sum of nicotine and six metabolites (NE7), accounts for more than 90% of a nicotine dose and is independent of individual metabolic differences. However, measuring NE7 is technically difficult and costly. We compared NE7, the gold standard of nicotine intake, with different combinations of fewer urinary nicotine metabolites. We also examined the impact of individual differences in nicotine metabolic rate, sex, and race on strength of association with NE7.

METHODS

Urine samples from 796 daily smokers, who participated across five clinical studies, were assayed for nicotine and/or metabolites. Associations with NE7 were assessed by regression and Bland-Altman analyses.

RESULTS

Overall, the molar sum of urine [cotinine + 3'-hydroxycotinine (3HC)] (NE2) and [nicotine + 
cotinine + 3HC] (NE3) were strongly correlated with NE7 (r = .97 and .99, respectively). However, in slow metabolizers NE2 was less predictive of NE7, whereas NE3 was equally robust. Urine total cotinine was also strongly correlated with NE7 (r = .87).

CONCLUSIONS

Urine NE3 is a robust biomarker of daily nicotine intake, independently of individual metabolic differences, whereas NE2 is less accurate in slow metabolizers. Our findings inform the selection of more rigorous and cost-effective measures to assess nicotine exposure in tobacco research studies.

IMPLICATIONS

The molar sum of urine total nicotine, cotinine and 3HC (NE3) is a robust biomarker of daily nicotine intake, independently of individual metabolic differences, and performs as well as measuring seven nicotine metabolites (NE7). The sum of cotinine and 3HC (NE2) is less accurate in slow metabolizers. Our findings inform the selection of more rigorous and cost-effective measures to assess nicotine exposure in tobacco research studies.

A qualitative study exploring cues and other motivators among a racially diverse sample of light and intermittent smokers

Introduction

Light and intermittent smokers (LITS) represent almost 50% of all current smokers. Research is needed to understand smoking motives among adult light smokers.

Aims

To explore smoking cues and motivators among a racially diverse sample of adult LITS (≤10 CPD). In addition, we explored differences between native (always smoked ≤10), and converted (former heavier) LITS.

Methods

We used purposive sampling to recruit participants who were native and converted LITS and to include equal numbers of African Americans, Whites and Latinos. We coded and analyzed transcripts using a stage approach to identify themes.

Results

Four main themes emerged that may be unique to light smokers and suggests potential strategies for intervention: (1) smoking in response to cues and control, (2) identifying as a smoker, (3) concern about health consequences, and (4) other priorities influencing smoking. There were some differences among smoking cues and motivators by race and ethnicity, and differences between native and converted LITS.

Conclusions

Overall, LITS reported drivers of smoking that were unrelated to symptoms of nicotine withdrawal. Even when experiencing salient cues, our LITS cohort expressed the ability to assert control over smoking by abstaining when situational contexts made smoking inconvenient.

Intent to quit, quit attempts, and perceived health risk reduction among African American, Latino, and White nondaily and daily smokers in the United States

Objective: Ethnic and racial differences in smoking patterns and behaviors have been well documented and most African American and Latino smokers are nondaily or light smokers. However, differences within smoking levels are understudied. Our primary aim was to determine whether there are racial and ethnic differences among African American, Latino, and White nondaily, light daily, and moderate to heavy daily smokers on (1) perceived health risk reduction, (2) intentions to quit, and (3) past year quit attempts. Design: Smokers were recruited through an online research panel for a cross-sectional survey (n = 2376). Sampling quotas were used to obtain equal numbers of African American, Latino, and White nondaily and daily smokers. Results: African American (59.6%) and Latino (54%) nondaily smokers were more likely than White nondaily smokers (45%) to currently limit their cigarettes per day (cpd) as a perceived health risk reduction strategy (p < 0.05). African American nondaily smokers were more likely than Latino and White nondaily smokers (p < 0.05) to limit their smoking in the past year as a perceived health risk reduction strategy (range: 0 'never' to 5 'always'; Means = 3.2, 2.9, 3.0, standard deviations [SD] = 1.1, 1.1, 1.2, respectively). African American nondaily smokers (15%) were more likely than either Latinos (7.8%) or Whites (8.5%) to intend to quit in the next 30 days (p < 0.01). African American (61.6%) and Latino (60.3%) nondaily smokers were more likely than Whites (49%) to have made a quit attempt in the past year (p < 0.01). Fewer racial and ethnic differences were found among daily smokers. Conclusions: Racial and ethnic group differences were more pronounced among nondaily smokers compared to light daily smoker and moderate to heavy daily smokers. Smoking level is an important consideration in understanding racial and ethnic variation in perceived health risk reduction and cessation-related behaviors.

Black Light Smokers: How Nicotine Intake and Carcinogen Exposure Differ Across Various Biobehavioral Factors

OBJECTIVE

The study objective was to identify biobehavioral variables associated with greater intake of nicotine and a tobacco carcinogen among Black light smokers who smoke 1 to 10 cigarettes per day (CPD).

METHODS

We analyzed baseline data collected from 426 Black light smokers enrolled in Kick It at Swope III (KIS III), a smoking cessation trial for Black smokers. We examined differences in concentrations of tobacco biomarkers, including urinary total nicotine equivalents (TNE) and total 4-(methylnitrosamino)-1-(3)pyridyl-1-butanonol (NNAL; a human carcinogen), across gender, age, plasma nicotine metabolite ratio (NMR), CPD, and measures of tobacco dependence, including time to first cigarette (TFC), using ANOVA.

RESULTS

Tobacco biomarker levels were significantly higher among those who smoked more CPD (6-10 vs 1-5 CPD) and those with greater reported physical dependence on tobacco. Concurrently, those who smoked 1-5 CPD smoked each cigarette more intensely than those who smoked 6-10 CPD. While we found no gender differences overall, among those who smoked 1-5 CPD, women had higher NNAL levels compared to men. The rate of nicotine metabolism, measured by the nicotine metabolite ratio, was not significantly related to TNE or NNAL levels.

CONCLUSION

Among Black Light smokers, higher cigarette consumption and greater physical dependence-but not rate of nicotine metabolism, menthol use, or socioeconomic status-were associated with greater toxicant exposure and thus a likely increased risk of tobacco-related diseases. The lack of data on light smokers, and specifically on Blacks, make this observation important given the disproportionate burden of lung cancer in this population.

A scoping review and meta-analysis of psychosocial and pharmacological treatments for cannabis and tobacco use among African Americans

The rates of co-occurring cannabis and tobacco use are higher among African Americans relative to other racial/ethnic groups. One plausible approach to treating co-use among African Americans is to examine the effectiveness of treatments for the sole use of cannabis and tobacco to identify effective approaches that might be combined to treat the dual use of these substances. The current meta-analysis sought to include studies that reported cannabis and/or tobacco use outcomes from randomized clinical trials (RCTs) with 100% African American samples. A total of 843 articles were considered for inclusion, 29 were reviewed by independent qualitative coders, and 22 were included in the review. There were no articles on cannabis use treatment with a 100% African American sample, resulting in a need to lower the threshold (60%) and conduct a scoping review of cannabis studies. Preliminary evidence from a small number of studies (k = 7) supports the use of Motivational Interviewing and Cognitive-Behavioral Therapy to treat cannabis use among African Americans, but not Contingency Management. Results from a meta-analysis of 15 tobacco studies found higher rates of smoking abstinence in the treatment condition relative to control conditions overall and across short and long-term follow-up periods. Significant differences in smoking abstinence were also found when examining the effects of pharmacological treatments relative to their control conditions. The clinical and research implications of these findings for future psychosocial and pharmacological trials for cannabis and tobacco use and co-use among African Americans are described. (PsycINFO Database Record

A randomized clinical trial of counseling and nicotine replacement therapy for treatment of African American non-daily smokers: Design, accrual, and baseline characteristics

BACKGROUND

Non-daily smokers (NDS) who smoke on some but not all days are a growing subset of United States (US) tobacco users. Racial/ethnic minorities are more likely to be NDS. African American NDS have strikingly high levels of nicotine and carcinogen exposure, making treatment of this high risk group a priority.

METHODS

The current study is one of three ongoing federally-funded clinical trials of NDS and, to our knowledge the only RCT focused on racial/ethnic minority NDS. The design has been guided by input from Patient and Stakeholder Advisory Panels who helped develop the research questions, design the intervention, and select the outcomes. The objective is to compare the effectiveness of smoking cessation counseling alone (C) or smoking cessation counseling plus participant's choice of nicotine replacement therapy (NRT; C + NRT) for African American NDS. Two-hundred seventy-eight African American NDS will be randomized in a 2:1 fashion to C + NRT or C. All participants receive five sessions of smoking cessation counseling; those randomized to C + NRT receive their choice of nicotine gum, patch, and/or lozenge. Treatment in both groups lasts for 12 weeks. We hypothesize that C + NRT will be more effective than C on the primary outcome of biochemically-confirmed abstinence from smoking at week 12. Secondary aims will compare C + NRT and C on patient- and provider-desired outcomes including abstinence from smoking at week 26, change in biochemically-verified nicotine and carcinogen exposure, days abstinent, and treatment process measures (e.g., NRT use and side effects). Predictors of abstinence will also be explored.

DISCUSSION

Findings will illuminate effective treatment options for African American NDS and contribute to development of evidence-based guidelines for treating the 8.9 million US adult NDS for whom no guidelines currently exist.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov: NCT02244918.

Relationships Between Smoking Behaviors and Cotinine Levels Among Two American Indian Populations With Distinct Smoking Patterns

Introduction

Smoking prevalence, cigarettes per day (CPD), and lung cancer incidence differ between Northern Plains (NP) and Southwest (SW) American Indian populations. We used cotinine as a biomarker of tobacco smoke exposure to biochemically characterize NP and SW smokers and nonsmokers and to investigate factors associated with variation in tobacco exposure.

Methods

American Indians (N = 636) were recruited from two different tribal populations (NP and SW) as part of a study conducted as part of the Collaborative to Improve Native Cancer Outcomes P50 project. For each participant, a questionnaire assessed smoking status, CPD, second-hand smoke exposure, and traditional ceremonial tobacco use; plasma and/or salivary cotinine was measured.

Results

Cotinine levels were (mean ± 95% confidence interval [CI]) 81.6 ± 14.1 and 21.3 ± 7.3 ng/ml among NP smokers and non-mokers, respectively, and 44.8 ± 14.4 and 9.8 ± 5.8 ng/ml among SW smokers and nonsmokers, respectively. Cotinine levels correlated with CPD in both populations (p < .0001). Cotinine ≥15 ng/ml was measured in 73.4% of NP smokers and 47.8% of SW smokers and in 19.0% of NP nonsmokers and 10.9% of SW nonsmokers. Ceremonial traditional tobacco use was associated with higher cotinine among NP smokers only (p = 0.004). Second-hand smoke exposure was associated with higher cotinine among NP non-smokers (P < 0.02). More secondhand smoke exposure was associated with smoking more CPD in both populations (p = 0.03-0.29). Linear regression modeling mirrored these findings.

Conclusions

High prevalence of smoking in the Northern Plains and high cotinine levels among nonsmokers in both regions highlights the tribal populations' risk for tobacco-related disease.

Implications

There is a high prevalence of smoking in Northern Plains American Indians. Among Northern Plains and Southwest nonsmokers, relatively high cotinine levels, representative of high tobacco exposure, suggest considerable exposure to second-hand smoke. It is critical to highlight the extent of second-hand smoke exposure among the Northern Plains and Southwest American Indians and to enhance efforts to initiate smoke-free policies in tribal communities, which are not subject to state-level polices.

Genome-wide association study of a nicotine metabolism biomarker in African American smokers: impact of chromosome 19 genetic influences

BACKGROUND AND AIMS

The activity of CYP2A6, the major nicotine-inactivating enzyme, is measurable in smokers using the nicotine metabolite ratio (NMR; 3'hydroxycotinine/cotinine). Due to its role in nicotine clearance, the NMR is associated with smoking behaviours and response to pharmacotherapies. The NMR is highly heritable (~80%), and on average lower in African Americans (AA) versus whites. We previously identified several reduce and loss-of-function CYP2A6 variants common in individuals of African descent. Our current aim was to identify novel genetic influences on the NMR in AA smokers using genome-wide approaches.

DESIGN

Genome-wide association study (GWAS).

SETTING

Multiple sites within Canada and the United States.

PARTICIPANTS

AA smokers from two clinical trials: Pharmacogenetics of Nicotine Addiction Treatment (PNAT)-2 (NCT01314001; n = 504) and Kick-it-at-Swope (KIS)-3 (NCT00666978; n = 450).

MEASUREMENTS

Genome-wide SNP genotyping, the NMR (phenotype) and population substructure and NMR covariates.

FINDINGS

Meta-analysis revealed three independent chromosome 19 signals (rs12459249, rs111645190 and rs185430475) associated with the NMR. The top overall hit, rs12459249 (P = 1.47e-39; beta = 0.59 per C (versus T) allele, SE = 0.045), located ~9.5 kb 3' of CYP2A6, remained genome-wide significant after controlling for the common (~10% in AA) non-functional CYP2A6*17 allele. In contrast, rs111645190 and rs185430475 were not genome-wide significant when controlling for CYP2A6*17. In total, 96 signals associated with the NMR were identified; many were not found in prior NMR GWASs in individuals of European descent. The top hits were also associated with the NMR in a third cohort of AA (KIS2; n = 480). None of the hits were in UGT or OCT2 genes.

CONCLUSIONS

Three independent chromosome 19 signals account for ~20% of the variability in the nicotine metabolite ratio in African American smokers. The hits identified may contribute to inter-ethnic variability in nicotine metabolism, smoking behaviours and tobacco-related disease risk.

Novel CYP2A6 diplotypes identified through next-generation sequencing are associated with in-vitro and in-vivo nicotine metabolism

OBJECTIVES

Smoking patterns and cessation rates vary widely across smokers and can be influenced by variation in rates of nicotine metabolism [i.e. cytochrome P450 2A6 (CYP2A6), enzyme activity]. There is high heritability of CYP2A6-mediated nicotine metabolism (60-80%) owing to known and unidentified genetic variation in the CYP2A6 gene. We aimed to identify and characterize additional genetic variants at the CYP2A6 gene locus.

METHODS

A new CYP2A6-specific sequencing method was used to investigate genetic variation in CYP2A6. Novel variants were characterized in a White human liver bank that has been extensively phenotyped for CYP2A6. Linkage and haplotype structure for the novel single nucleotide polymorphisms (SNPs) were assessed. The association between novel five-SNP diplotypes and nicotine metabolism rate was investigated.

RESULTS

Seven high-frequency (minor allele frequencies ≥6%) noncoding SNPs were identified as important contributors to CYP2A6 phenotypes in a White human liver bank (rs57837628, rs7260629, rs7259706, rs150298687 (also denoted rs4803381), rs56113850, rs28399453, and rs8192733), accounting for two times more variation in in-vitro CYP2A6 activity relative to the four established functional CYP2A6 variants that are frequently tested in Whites (CYP2A6*2, *4, *9, and *12). Two pairs of novel SNPs were in high linkage disequilibrium, allowing us to establish five-SNP diplotypes that were associated with CYP2A6 enzyme activity (rate of nicotine metabolism) in-vitro in the liver bank and in-vivo among smokers.

CONCLUSION

The novel five-SNP diplotype may be useful to incorporate into CYP2A6 genotype models for personalized prediction of nicotine metabolism rate, cessation success, and response to pharmacotherapies.

Sex Differences in Smoking Cessation Pharmacotherapy Comparative Efficacy: A Network Meta-analysis

Introduction

Converging clinical and biological evidence suggest sex is an important factor when selecting a pharmacological intervention for smoking cessation. The current investigation used network meta-analyses to estimate sex differences in the comparative efficacy of transdermal nicotine (TN), varenicline, and sustained release (SR) bupropion for smoking cessation.

Methods

Systematically searched previously published reviews and databases (Medline, PsycINFO, Embase) of randomized, double-blind, placebo-controlled trials of bupropion-SR, TN, and varenicline for cigarette smoking cessation in primary care/general community samples were included.

Results

Thirty-two studies met all criteria and 28 (88%) were included in the final analyses, representing 14 389 smokers (51% female). Results of the full sample (women and men combined) mirrored those from a Cochrane Tobacco Addiction Group network meta-analysis of smoking cessation pharmacotherapy, showing VAR>TN=BUP. All medications improved quit rates over placebo for both women and men. Relative to placebo, varenicline efficacy was similar for women and men. Significant sex differences were evident when comparing varenicline versus TN and varenicline versus bupropion. For women, varenicline was more efficacious than TN (RR = 1.41; 95% CI = 1.12,1.76) and bupropion (RR = 1.38; 95% CI = 1.08,1.77). For men, outcomes for those treated with TN and bupropion were similar to those treated with varenicline. There were no differences in efficacy when comparing bupropion versus TN.

Conclusions

The advantage of varenicline over bupropion SR and TN is greater for women than men. Clinicians should strongly consider varenicline as the first option treatment for women. Among men, the advantage of varenicline over TN or bupropion is less clear.

Implications

This study provides information for the sex-informed treatment of nicotine addiction among cigarette smokers. Relative to placebo, women and men achieved similar outcomes when treated with varenicline; however the advantages of varenicline over transdermal patch and bupropion were greater for women compared to men.

Pharmacotherapy for smoking cessation: effects by subgroup defined by genetically informed biomarkers

BACKGROUND

Smoking cessation therapies are not effective for all smokers, and researchers are interested in identifying those subgroups of individuals (e.g. based on genotype) who respond best to specific treatments.

OBJECTIVES

To assess whether quit rates vary by genetically informed biomarkers within pharmacotherapy treatment arms and as compared with placebo. To assess the effects of pharmacotherapies for smoking cessation in subgroups of smokers defined by genotype for identified genome-wide significant polymorphisms.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group specialised register, clinical trial registries, and genetics databases for trials of pharmacotherapies for smoking cessation from inception until 16 August 2016.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that recruited adult smokers and reported pharmacogenomic analyses from trials of smoking cessation pharmacotherapies versus controls. Eligible trials included those with data on a priori genome-wide significant (P < 5 × 10-8) single-nucleotide polymorphisms (SNPs), replicated non-SNPs, and/or the nicotine metabolite ratio (NMR), hereafter collectively described as biomarkers.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. The primary outcome was smoking abstinence at six months after treatment. The secondary outcome was abstinence at end of treatment (EOT). We conducted two types of meta-analyses- one in which we assessed smoking cessation of active treatment versus placebo within genotype groups, and another in which we compared smoking cessation across genotype groups within treatment arms. We carried out analyses separately in non-Hispanic whites (NHWs) and non-Hispanic blacks (NHBs). We assessed heterogeneity between genotype groups using T², I², and Cochrane Q statistics.

MAIN RESULTS

Analyses included 18 trials including 9017 participants, of whom 6924 were NHW and 2093 NHB participants. Data were available for the following biomarkers: nine SNPs (rs1051730 (CHRNA3); rs16969968, rs588765, and rs2036527 (CHRNA5); rs3733829 and rs7937 (in EGLN2, near CYP2A6); rs1329650 and rs1028936 (LOC100188947); and rs215605 (PDE1C)), two variable number tandem repeats (VNTRs; DRD4 and SLC6A4), and the NMR. Included data produced a total of 40 active versus placebo comparisons, 16 active versus active comparisons, and 64 between-genotype comparisons within treatment arms.For those meta-analyses showing statistically significant heterogeneity between genotype groups, we found the quality of evidence (GRADE) to be generally moderate. We downgraded quality most often because of imprecision or risk of bias due to potential selection bias in genotyping trial participants. Comparisons of relative treatment effects by genotypeFor six-month abstinence, we found statistically significant heterogeneity between genotypes (rs16969968) for nicotine replacement therapy (NRT) versus placebo at six months for NHB participants (P = 0.03; n = 2 trials), but not for other biomarkers or treatment comparisons. Six-month abstinence was increased in the active NRT group as compared to placebo among participants with a GG genotype (risk ratio (RR) 1.47, 95% confidence interval (CI) 1.07 to 2.03), but not in the combined group of participants with a GA or AA genotype (RR 0.43, 95% CI 0.15 to 1.26; ratio of risk ratios (RRR) GG vs GA or AA of 3.51, 95% CI 1.19 to 10.3). Comparisons of treatment effects between genotype groups within pharmacotherapy randomisation armsFor those receiving active NRT, treatment was more effective in achieving six-month abstinence among individuals with a slow NMR than among those with a normal NMR among NHW and NHB combined participants (normal NMR vs slow NMR: RR 0.54, 95% CI 0.37 to 0.78; n = 2 trials). We found no such differences in treatment effects between genotypes at six months for any of the other biomarkers among individuals who received pharmacotherapy or placebo.

AUTHORS' CONCLUSIONS

We did not identify widespread differential treatment effects of pharmacotherapy based on genotype. Some genotype groups within certain ethnic groups may benefit more from NRT or may benefit less from the combination of bupropion with NRT. The reader should interpret these results with caution because none of the statistically significant meta-analyses included more than two trials per genotype comparison, many confidence intervals were wide, and the quality of this evidence (GRADE) was generally moderate. Although we found evidence of superior NRT efficacy for NMR slow versus normal metabolisers, because of the lack of heterogeneity between NMR groups, we cannot conclude that NRT is more effective for slow metabolisers. Access to additional data from multiple trials is needed, particularly for comparisons of different pharmacotherapies.

Effect of a smoking cessation intervention for women in subsidized neighborhoods: A randomized controlled trial

OBJECTIVE

To evaluate the effectiveness of a community based participatory research (CBPR) developed, multi-level smoking cessation intervention among women in subsidized housing neighborhoods in the Southeastern US.

METHODS

A total of n=409 women in 14 subsidized housing neighborhoods in Georgia and South Carolina participated in this group randomized controlled trial conducted from 2009 to 2013. Intervention neighborhoods received a 24-week intervention with 1:1 community health worker contact, behavioral peer group sessions, and nicotine replacement. Control neighborhoods received written cessation materials at weeks 1, 6, 12, 18. Random coefficient models were used to compare smoking abstinence outcomes at 6 and 12months. Significance was set a p<0.05.

RESULTS

The majority of participants (91.2%) were retained during the 12-month intervention period. Smoking abstinence rates at 12months for intervention vs. control were 9% vs. 4.3%, p=0.05. Additional analyses accounting for passive smoke exposure in these multi-unit housing settings demonstrated 12month abstinence rates of 12% vs. 5.3%, p=0.016. However, in the multivariate regression analyses, there was no significant effect of the intervention on the odds of being a non-smoker (OR=0.44, 95% CI: 0.18-1.07). Intervention participants who kept coach visits, attended group sessions, and used patches were more likely to remain abstinent.

CONCLUSIONS

This CBPR developed intervention showed potential to engage smokers and reduce smoking among women in these high-poverty neighborhoods. Effectiveness in promoting cessation in communities burdened with fiscal, environmental and social inequities remains a public health priority.

Varenicline for Smoking Cessation in Light Smokers

INTRODUCTION

As the prevalence of cigarette smoking has declined, the proportion of smokers who smoke less than 10 cigarettes/day (cpd) has increased. Varenicline may provide an effective pharmacotherapeutic treatment option for increasing smoking abstinence rates among light smokers.

METHODS

We conducted a randomized, placebo-controlled clinical trial evaluating the efficacy of varenicline for increasing smoking abstinence rates among light smokers (5-10 cpd). Participants received varenicline or placebo for 12 weeks. Outcomes were assessed at 3 and 6 months.

RESULTS

Ninety-three participants were randomized. Fifty-two percent of participants terminated the study early. At end-of-treatment (3 months), the point prevalence smoking abstinence rate was 53.3% in the varenicline group compared to 14.5% in placebo (odds ratio [OR]: 6.69, 95% confidence interval [CI]: 2.48-18.06, P < .001), and the prolonged smoking abstinence rate was 40.0% and 8.3%, respectively (OR: 7.33, 95% CI: 2.24-23.98, P = .001). At end-of-study (6 months), the point prevalence smoking abstinence rate was 40.0% in the varenicline group compared to 20.8% in placebo (OR: 2.53, 95% CI: 1.01-6.34, P = .047), and the prolonged smoking abstinence rate was 31.1% and 8.3%, respectively (OR: 4.97, 95% CI: 1.49-16.53, P = .009). The estimated magnitude of the treatment effect remained consistent across the various missing data assumptions and in analyses that adjusted for gender. Nausea and sleep disturbance were more commonly reported in the varenicline group.

CONCLUSIONS

Varenicline was safe and effective for increasing long-term smoking abstinence rates in a population of predominantly White light cigarette smoker. The efficacy of varenicline in this study was comparable to that observed in heavier smokers.

IMPLICATIONS

Our findings demonstrate that varenicline is effective for increasing smoking cessation in light smokers. Our findings have implications for advancing the treatment of light smokers in clinical practice.

Adult Cigarette Smokers at Highest Risk for Concurrent Alternative Tobacco Product Use Among a Racially/Ethnically and Socioeconomically Diverse Sample

INTRODUCTION

Rates of alternative tobacco product use (ATPs; eg, cigars, cigarillos, pipes) among cigarette smokers are on the rise but little is known about the subgroups at highest risk. This study explored interactions between demographic, tobacco, and psychosocial factors to identify cigarette smokers at highest risk for ATP use from a racially/ethnically and socioeconomically diverse sample of adult smokers across the full smoking spectrum (nondaily, daily light, daily heavy).

METHODS

Two-thousand three-hundred seventy-six adult cigarette smokers participated in an online cross-sectional survey. Quotas ensured equal recruitment of African American (AA), white (W), Hispanic/Latino (H) as well as daily and nondaily smokers. Classification and Regression Tree modeling was used to identify subgroups of cigarette smokers at highest risk for ATP use.

RESULTS

51.3% were Cig+ATP smokers. Alcohol for men and age, race/ethnicity, and discrimination for women increased the probability of ATP use. Strikingly, 73.5% of men screening positive for moderate to heavy drinking and 62.2% of younger (≤45 years) African American/Hispanic/Latino women who experienced regular discrimination were Cig+ATP smokers.

CONCLUSIONS

Screening for concurrent ATP use is necessary for the continued success of tobacco cessation efforts especially among male alcohol users and racial/ethnic minority women who are at greatest risk for ATP use.

A clinical trial to examine disparities in quitting between African-American and White adult smokers: Design, accrual, and baseline characteristics

BACKGROUND

African-Americans smoke fewer cigarettes per day than Whites but experience greater smoking attributable morbidity and mortality. African-American-White differences may also exist in cessation but rigorously designed studies have not been conducted to empirically answer this question.

METHODS/DESIGN

Quit2Live is, to our knowledge, the first head-to-head trial designed with the primary aim of examining African-American-White disparities in quitting smoking. Secondary aims are to identify mechanisms that mediate and/or moderate the relationship between race and quitting. The study is ongoing. Study aims are accomplished through a 5-year prospective cohort intervention study designed to recruit equal numbers of African-Americans (n=224) and Whites (n=224) stratified on age (<40, ≥40) and gender, key factors known to impact cessation, and all within a restricted income range (≤400% federal poverty level). All participants will receive 12 weeks of varenicline in combination with smoking cessation counseling. The primary outcome is cotinine-verified 7-day point prevalence abstinence from smoking at week 26. Secondary outcomes are cotinine-verified 7-day point prevalence abstinence from smoking at weeks 4 and 12.

DISCUSSION

Findings from Quit2Live will not only address if African-American-White disparities in quitting smoking exist but, more importantly, will examine mechanisms underlying the difference. Attention to proximal, modifiable mechanisms (e.g., adherence, response to treatment, depression, stress) maximizes Quit2Live's potential to inform practice. Findings will provide an empirically-derived approach that will guide researchers and clinicians in identifying specific factors to address to improve cessation outcomes and reduce tobacco-related morbidity and mortality in African-American and White smokers.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov: NCT01836276.

Reversion of AHRR Demethylation Is a Quantitative Biomarker of Smoking Cessation

Smoking is the largest preventable cause of morbidity and mortality in the world. Although there are effective pharmacologic and behavioral treatments for smoking cessation, our inability to objectively quantify smokers' progress in decreasing smoking has been a barrier to both clinical and research efforts. In prior work, we and others have shown that DNA methylation at cg05575921, a CpG residue in the aryl hydrocarbon receptor repressor (AHRR), can be used to determine smoking status and infer cigarette consumption history. In this study, we serially assessed self-report and existing objective markers of cigarette consumption in 35 subjects undergoing smoking cessation therapy, then quantified DNA methylation at cg05575921 at study entry and three subsequent time points. Five subjects who reported serum cotinine and exhaled carbon monoxide verified smoking abstinence for the 3 months prior to study exit averaged a 5.9% increase in DNA methylation at cg05575921 (p < 0.004) over the 6-month study. Although the other 30 subjects did not achieve smoking cessation at the 6-month time point, their self-reported reduction of cigarette consumption (mean = 6 cigarettes/day) was associated with a 2.8% increase DNA methylation at cg05575921 (p < 0.05). Finally, a survey of subjects as they exited the study demonstrated strong support for the clinical use of epigenetic biomarkers. We conclude that AHRR methylation status is a quantifiable biomarker for progress in smoking cessation that could have substantial impact on both smoking cessation treatment and research.

Genetic and phenotypic variation in UGT2B17, a testosterone-metabolizing enzyme, is associated with BMI in males

OBJECTIVE

A number of candidate gene and genome-wide association studies have identified significant associations between single nucleotide polymorphisms, particularly in FTO and MC4R, and body weight. However, the association between copy number variation and body weight is less understood. Anabolic androgenic steroids, such as testosterone, can regulate body weight. In humans, UDP-glucuronosyltransferase 2B17 (UGT2B17) metabolizes testosterone to a metabolite, which is readily excreted in urine. We investigate the association between genetic and phenotypic variation in UGT2B17 and body weight.

MATERIALS AND METHODS

UGT2B17 deletion was genotyped and in-vivo UGT2B17 enzymatic activity (as measured by the 3-hydroxycotinine glucuronide to free 3-hydroxycotinine ratio) was measured in 400 Alaska Native individuals and 540 African Americans.

RESULTS

In Alaska Native people, UGT2B17 deletion was strongly associated with lower BMI in male individuals (P<0.001), but not in female individuals, consistent with testosterone being a male dominant steroid. The sex-specific association between UGT2B17 deletion and lower BMI was also observed in African Americans (P=0.01 in male individuals). In both populations, UGT2B17 deletion was significantly associated with lower measured in-vivo UGT2B17 activity. In male individuals, lower in-vivo UGT2B17 activity was associated with lower BMI, as observed in the sex-specific genotypic association.

CONCLUSION

These data suggest that UGT2B17 deletion leads to reduced UGT2B17 activity, and lower BMI in male individuals. This is consistent with the hypothesis that reduced UGT2B17-mediated testosterone excretion results in higher testosterone levels. Future studies could confirm this hypothesis by directly measuring serum testosterone levels.

Community-based navigators for tobacco cessation treatment: a proof-of-concept pilot study among low-income smokers

BACKGROUND

A majority of continuing smokers in the United States are socioeconomically disadvantaged (SED) adults, who are less likely than others to achieve and maintain abstinence despite comparable quit-attempt rates. A national research initiative seeks effective new strategies for increasing successful smoking cessation outcomes among SED populations. There is evidence that chronic and acute stressors may interfere with SED smokers who try to quit on their own. Patient navigators have been effectively used to improve adherence to chronic disease treatment. We designed and have pilot-tested an innovative, non-clinical community-based intervention--smoking cessation treatment navigators--to determine feasibility (acceptance, adherence, and uncontrolled results) for evaluation by randomized controlled trial (RCT).

METHODS

The intervention was developed for smokers among parents and other household members of inner city pre-school for low-income children. Smoking cessation treatment navigators were trained and deployed to help participants choose and adhere to evidence-based cessation treatment (EBCT). Navigators provided empathy, resource-linking, problem-solving, and motivational reinforcement. Measures included rates of study follow-up completion, EBCT utilization, navigation participation, perceived intervention quality, 7-day point abstinence and longest abstinence at three months. Both complete-case and intent-to-treat analyses were performed.

RESULTS

Eighty-five percent of study participants (n = 40) completed final data collection. More than half (53%) enrolled in a telephone quitline and nearly three-fourths (71%) initiated nicotine replacement therapy. Participants completed a mean 3.4 navigation sessions (mean 30 min duration) and gave the intervention very high quality and satisfaction ratings. Self-reported abstinence was comparable to rates for evidence-based cessation strategies (21% among study completers, 18% using intent-to-treat analysis; median 21 days abstinent among relapsers).

CONCLUSIONS

The pilot results suggest that smoking cessation treatment navigators are feasible to study in community settings and are well-accepted for increasing use of EBCT among low-income smokers. Randomized controlled trial for efficacy is warranted.

Smoking dependence across the levels of cigarette smoking in a multiethnic sample

OBJECTIVES

The Brief Wisconsin Inventory of Smoking Dependence Motives (WISDM) is a multi-dimensional smoking dependence measure that assesses primary dependence motives (PDM; e.g., core dependence marked by tolerance, craving) and secondary dependence motives (SDM; e.g., auxiliary dependence motives such as cognitive enhancement, weight control). However, the relationship between PDM, SDM, and smoking level remains unclear. Thus, we examined these scales across smoking levels in a diverse sample of smokers.

METHODS

Participants were 2376 African American, Latino, and non-Hispanic White smokers recruited using an online panel research company. The sample included 297 native nondaily smokers (never smoked daily), 297 converted nondaily smoker (previously smoked daily for ≥six months), 578 light daily smokers (≤10 cigarettes per day [cpd]), and 597 moderate to heavy daily smokers (>10cpd).

METHODS

Results of a multinomial logistic regression showed that for each unit increase in SDM, after controlling for PDM, the odds of being a native nondaily, converted nondaily or light smoker vs. moderate to heavy smoker increased by 29% to 56% (ps<0.001). In the model, higher PDM scores were associated with lower odds of being a native nondaily, converted nondaily, or light smoker vs. a moderate to heavy daily smoker (ps<0.001).

CONCLUSION

Nondaily and light smokers endorse higher secondary dependence motives relative to their primary dependence motives. Smoking cessation trials for nondaily and light smokers might address these secondary motives within the context of counseling intervention to enhance abstinence.

JNCI and cancer prevention

The Journal of the National Cancer Institute (JNCI), with its broad coverage of bench research, epidemiologic studies, and clinical trials, has a long history of publishing practice-changing studies in cancer prevention and public health. These include studies of tobacco cessation, chemoprevention, and nutrition. The landmark Breast Cancer Prevention Trial (BCPT)-the first large trial to prove efficacy of a preventive medication for a major malignancy-was published in the Journal, as were key ancillary papers to the BCPT. Even when JNCI was not the publication venue for the main trial outcomes, conceptual and design discussions leading to the trial as well as critical follow-up analyses based on trial data from the Prostate Cancer Prevention Trial (PCPT) and the Selenium and Vitamin E Chemoprevention Trial (SELECT) were published in the Journal. The Journal has also published important evidence on very charged topics, such as the purported link between abortion and breast cancer risk. In summary, JNCI has been at the forefront of numerous major publications related to cancer prevention.

Variation in P450 oxidoreductase (POR) A503V and flavin-containing monooxygenase (FMO)-3 E158K is associated with minor alterations in nicotine metabolism, but does not alter cigarette consumption

The rates of nicotine metabolism differ widely, even after controlling for genetic variation in the major nicotine-metabolizing enzyme, CYP2A6. Genetic variants in an additional nicotine-metabolizing enzyme, flavin-containing monooxygenase (FMO)-3, and an obligate microsomal CYP-supportive enzyme, cytochrome P450 oxidoreductase (POR), were investigated. We examined the impact of FMO3 E158K and POR A503V before and after stratifying by CYP2A6 metabolism group. In 130 nonsmokers of African descent who received 4 mg oral nicotine, FMO3 158K trended toward slower nicotine metabolism in reduced CYP2A6 metabolizers (P=0.07) only, whereas POR 503V was associated with faster CYP2A6 activity (nicotine metabolite ratio) in normal (P=0.03), but not reduced, CYP2A6 metabolizers. Neither FMO3 158K nor POR 503V significantly altered the nicotine metabolic ratio (N=659), cigarette consumption (N=667), or urine total nicotine equivalents (N=418) in smokers of African descent. Thus, FMO3 E158K and POR A503V are minor sources of nicotine metabolism variation, insufficient to appreciably alter smoking.

Gene variants in CYP2C19 are associated with altered in vivo bupropion pharmacokinetics but not bupropion-assisted smoking cessation outcomes

Bupropion is used clinically to treat depression and to promote smoking cessation. It is metabolized by CYP2B6 to its active metabolite hydroxybupropion, yet alterations in CYP2B6 activity have little impact on bupropion plasma levels. Furthermore, less than 10% of a bupropion dose is excreted as urinary bupropion and its characterized metabolites hydroxybupropion, threohydrobupropion, and erythrohydrobupropion, suggesting that alternative metabolic pathways may exist. In vitro data suggested CYP2C19 could metabolize bupropion. The current study investigated the impact of functional CYP2C19 genetic variants on bupropion pharmacokinetics and treatment outcomes. In 42 healthy volunteers, CYP2C19*2 (a reduced activity allele) was associated with higher bupropion area under the plasma concentration-time curve (AUC), but similar hydroxybupropion AUC. The mean bupropion AUC was 771 versus 670 hours⋅ng/ml in individuals with and without CYP2C19*2, respectively (P = 0.017). CYP2C19*2 was also associated with higher threohydrobupropion and erythrohydrobupropion AUC (P < 0.005). Adjusting for CYP2B6 genotype did not alter these associations, and CYP2C19 variants did not alter the utility of the hydroxybupropion/bupropion ratio as a measure of CYP2B6 activity. Finally, in a clinical trial of 540 smokers, CYP2C19 genotype was not associated with smoking cessation outcomes, supporting the hypothesis that bupropion response is mediated by hydroxybupropion, which is not altered by CYP2C19. In conclusion, our study reports the first in vivo evidence that reduced CYP2C19 activity significantly increases the steady-state exposure to bupropion and its reductive metabolites threohydrobupropion and erythrohydrobupropion. These pharmacokinetic changes were not associated with differences in bupropion's ability to promote smoking cessation in smokers, but may influence the side effects and toxicity associated with bupropion.