Bayesian regularization to predict neuropsychiatric adverse events in smoking cessation with pharmacotherapy

BACKGROUND

Research on risk factors for neuropsychiatric adverse events (NAEs) in smoking cessation with pharmacotherapy is scarce. We aimed to identify predictors and develop a prediction model for risk of NAEs in smoking cessation with medications using Bayesian regularization.

METHODS

Bayesian regularization was implemented by applying two shrinkage priors, Horseshoe and Laplace, to generalized linear mixed models on data from 1203 patients treated with nicotine patch, varenicline or placebo. Two predictor models were considered to separate summary scores and item scores in the psychosocial instruments. The summary score model had 19 predictors or 26 dummy variables and the item score model 51 predictors or 58 dummy variables. A total of 18 models were investigated.

RESULTS

An item score model with Horseshoe prior and 7 degrees of freedom was selected as the final model upon model comparison and assessment. At baseline, smokers reporting more abnormal dreams or nightmares had 16% greater odds of experiencing NAEs during treatment (regularized odds ratio (rOR) = 1.16, 95% credible interval (CrI) = 0.95 - 1.56, posterior probability P(rOR > 1) = 0.90) while those with more severe sleep problems had 9% greater odds (rOR = 1.09, 95% CrI = 0.95 - 1.37, P(rOR > 1) = 0.85). The prouder a person felt one week before baseline resulted in 13% smaller odds of having NAEs (rOR = 0.87, 95% CrI = 0.71 - 1.02, P(rOR < 1) = 0.94). Odds of NAEs were comparable across treatment groups. The final model did not perform well in the test set.

CONCLUSIONS

Worse sleep-related symptoms reported at baseline resulted in 85%-90% probability of being more likely to experience NAEs during smoking cessation with pharmacotherapy. Treatment for sleep disturbance should be incorporated in smoking cessation program for smokers with sleep disturbance at baseline. Bayesian regularization with Horseshoe prior permits including more predictors in a regression model when there is a low number of events per variable.

Smoking cessation patterns, usefulness of quitting methods, and tobacco cessation motivators and barriers to quit in patients with rheumatoid arthritis

OBJECTIVE

Tobacco use is highly discouraged in patients with rheumatoid arthritis (RA) due to related short and long-term health implications. We aimed to evaluate smoking cessation patterns in patients with RA. In addition, we ascertained perceptions on the usefulness of quitting methods, and perceived motivators and barriers to quit.

METHODS

We surveyed adults with RA enrolled in the FORWARD Databank who self-identified as former or current tobacco users.

RESULTS

Three hundred forty-eight participants completed the survey and responded to the question "do you currently smoke" (former use = 319; current use = 29). Nicotine replacement therapy (NRT) was perceived as extremely/somewhat useful by 31%, followed by individual 27% and group counseling 21%. Experiencing a major health event was the most common motivator to quit. Current users on average smoked 17 cigarettes per day. Six of the 29 current users had used electronic cigarettes in the past 30 days. The most frequent methods used to quit were "cold turkey quitting," NRT, and prescription medicines. Only 8 of the 23 current users had plans to quit or expressed being ready to make changes to quit. Reasons most frequently listed to not quit were using smoking to manage negative emotions, as a pleasurable habit, to manage other addictions, and to provide a sense of control (e.g., to cope with RA).

CONCLUSIONS

Current users expressed several negative emotions including coping with the disease and "being a pleasurable habit" when trying to quit. Future cessation programs should address these barriers to support patients with RA. Key Points • First study characterizing the smoking behavior of patients with RA in the USA. Current users were younger, had a shorter disease duration, and worse disease outcomes compared to former smokers. • Former and current users reported similar motivators to quit, with experiencing a major health event being most common. Only about a third of participants who quit or who were still smoking received advice from a health professional. • The most common reasons for not quitting were that smoking help to manage negative emotions and was a pleasurable habit. Future studies should focus on cessation programs that support participants with RA by addressing the unique perceptions about smoking in this population.

A systematic review and meta-analysis of e-cigarette use among cancer survivors

PURPOSE

We conducted a systematic review and meta-analysis to determine the use of e-cigarettes among cancer survivors, factors associated with their use, and prevalence of e-cigarette use as a quit attempt.

METHODS

We searched five electronic databases until June 2022. Two authors independently selected studies, appraised their quality, and collected data.

RESULTS

Twenty-three publications from eight data sources (national surveys) met our eligibility criteria. The pooled rate of lifetime e-cigarette use among cancer survivors was 15% (95% CI 6-27%); current use was 3% (95% CI 0-8%). Among survivors who currently used traditional cigarettes, 63% (95% CI 57-69%) also used e-cigarettes. The reported rates of weighted lifetime e-cigarette use differed between age groups (18-44 years, up to 46.7%; 45-64, up to 27.2%; ≥65, up to 24.8%). Nine publications reported factors associated with lifetime e-cigarette use (i.e., active use of traditional cigarettes; heavy drinking; poor mental health; younger age; being male, non-Hispanic White, or single; having less than high school education or income ≤$25,000 USD; and living in the South regions of the US or urban areas). E-cigarettes were used as a quit resource by 75% of survivors reporting dual use of electronic and traditional cigarettes (95% CI 63%, 85%).

CONCLUSION

More than two-thirds of survivors currently using traditional cigarettes also use e-cigarettes. Higher use rates of e-cigarettes were reported among young cancer survivors compared to older survivors. Future studies are needed to assess the impact of e-cigarettes on long-term health and improve screening of smoking behaviors.

IMPLICATIONS FOR CANCER SURVIVORS

Our study provides an overview of the prevalence of e-cigarette use and sociodemographic risk factors associated with e-cigarette use among cancer survivors. The findings can assist providers in supporting attempts to quit among cancer survivors.

A systematic review with meta-analysis of the effects of smoking cessation strategies in patients with rheumatoid arthritis

OBJECTIVE

Smoking rates among patients with rheumatoid arthritis (RA) exceed those in the general population. This study identified smoking cessation strategies used in patients with RA and synthesized data on their effects.

METHODS

We conducted a systematic review of studies that reported effects of interventions for smoking cessation in patients with RA. We searched 5 electronic databases until March 2022. Screening, quality appraisal, and data collection were done independently by 2 reviewers.

RESULTS

We included 18 studies reporting interventions for patients or providers: 14 evaluated strategies for patients (5 education on cardiovascular risk factors including smoking, 3 educational interventions on smoking cessation alone, 3 education with nicotine replacement and counseling, and 1 study each: education with nicotine replacement, counseling sessions alone, and a social marketing campaign). Smoking cessation rates ranged from 4% (95% CI: 2%-6%, 24 to 48 weeks) for cardiovascular risk education to 43% (95% CI: 21%-67%, 104 weeks) for counseling sessions alone. The pooled cessation rate for all interventions was 22% (95% CI: 8%-41%, 4 weeks to 104 weeks; 9 studies). Four interventions trained providers to ascertain smoking status and provide referrals for smoking cessation. The pooled rates of referrals to quit services increased from 5% in pre-implementation populations to 70% in post-implementation populations.

CONCLUSION

Studies varied in patient characteristics, the interventions used, and their implementation structure. Only 3 studies were controlled clinical trials. Additional controlled studies are needed to determine best practices for smoking cessation for patients with RA.

Evaluating Treatment Mechanisms of Varenicline: Mediation by Affect and Craving

INTRODUCTION

Negative reinforcement models posit that relapse to cigarette smoking is driven in part by changes in affect and craving during the quit attempt. Varenicline may aid cessation by attenuating these changes; however, this mediational pathway has not been formally evaluated in placebo-controlled trials. Thus, trajectories of negative affect (NA), positive affect (PA), and craving were tested as mediators of the effect of varenicline on smoking cessation.

AIMS AND METHODS

Secondary data analysis was conducted on 828 adults assigned to either varenicline or placebo in a randomized controlled trial for smoking cessation (NCT01314001). Self-reported NA, PA, and craving were assessed 1-week pre-quit, on the target quit day (TQD), and 1 and 4 weeks post-TQD.

RESULTS

Across time, NA peaked 1-week post-quit, PA did not change, and craving declined. Less steep rises in NA (indirect effect 95% CI: .01 to .30) and lower mean craving at 1-week post-quit (CI: .06 to .50) were mediators of the relationship between varenicline and higher cessation rates at the end of treatment. PA was associated with cessation but was not a significant mediator.

CONCLUSIONS

These results partially support the hypothesis that varenicline improves smoking cessation rates by attenuating changes in specific psychological processes and supported NA and craving as plausible treatment mechanisms of varenicline.

IMPLICATIONS

The present research provides the first evidence from a placebo-controlled randomized clinical trial that varenicline's efficacy is due, in part, to post-quit attenuation of NA and craving. Reducing NA across the quit attempt and craving early into the attempt may be important treatment mechanisms for effective interventions. Furthermore, post-quit NA, PA, and craving were all associated with relapse and represent treatment targets for future intervention development.

Engaging smokers in research: Utility of Facebook in facilitating recruitment to a smoking cessation study

INTRODUCTION

Social media, including Facebook outreach, is increasingly being used as a participant recruitment tool, and may be particularly useful in tobacco and smoking cessation studies. The Recruitment Innovation Center at Vanderbilt University Medical Center partnered with Project LUNA, a smoking cessation study, to conduct a pilot social media campaign aimed at increasing study recruitment.

METHODS

Two posts encouraging study participation were developed and promoted on Facebook to users with an interest in smoking-related topics, with a link to a study-specific webpage. Facebook and website analytics were collected, including impressions, clicks, click-through rates, website traffic, and clicks to the study screening form. Study screening and enrollment data were also collected.

RESULTS

The Facebook campaign ran in June 2019 in the greater Houston area. In total, the Facebook posts logged 1,179,844 impressions, 6490 clicks, and an overall click-through rate of 0.55%. There were no differences in response to the two different promotional posts. Approximately 3812 unique individuals visited an intermediary study page, with 473 expressing interest in the study. Forty-three potential participants contacted the study team, resulting in study enrollment and randomization of 23 participants, with an estimated cost per enrolled participant of $441.

CONCLUSIONS

The social media campaign was successful at increasing outreach and interest in the LUNA study. However, the price-per-participant enrolled was higher than in comparable tobacco cessation studies. These results and lessons learned may be beneficial to others considering social media as a recruitment method for their clinical research trial.

Socioeconomic Status, Social Context, and Smoking Lapse During a Quit Attempt: An Ecological Momentary Assessment Study

BACKGROUND

Low socioeconomic status (SES) is linked to failure to quit smoking. Health inequity models suggest that low SES smokers experience barriers to quitting in part due to greater exposure to pro-smoking social contexts.

PURPOSE

The current study examined longitudinal associations among socioeconomic status, pro-smoking social context factors (i.e., exposure to other smokers, places where smoking was allowed), cigarette availability, and smoking lapse during a quit attempt.

METHODS

Ecological momentary assessments (EMA) were gathered from a multiethnic sample of 365 smokers engaged in a quit attempt. A multilevel structural equation model estimated a latent variable for SES indicated by income, education, health insurance, and employment, associations among EMAs for pro-smoking social contexts and cigarette availability, and indirect effects of SES through, pro-smoking social contexts and cigarette availability to subsequent smoking lapse.

RESULTS

Lower SES scores were associated with a higher likelihood of smoking lapse. Decomposition of the path from SES to smoking lapse into indirect effects showed significant paths through exposure to places where smoking is allowed and cigarette availability. Additionally, significant serial indirect paths from SES through both exposure to other smokers and places where smoking was allowed, in turn, through cigarette availability, and, ultimately, to smoking lapse were noted.

CONCLUSIONS

Consistent with models positing that SES influences health behaviors via contextual factors, the current study demonstrated that low SES smokers attempting to quit experienced greater pro-smoking social contexts that affected subsequent risk for lapse.

Comparing the Rate of Nicotine Metabolism Among Smokers With Current or Past Major Depressive Disorder

BACKGROUND AND OBJECTIVES

Persons with current or past major depressive disorder (MDD) vs those without have higher smoking rates. The nicotine metabolite ratio (NMR) represents variation in the rate of nicotine metabolism and has been associated with smoking behaviors and response to tobacco treatments. We compared NMR between smokers with current or past MDD (MDD+) vs smokers without MDD (MDD-). We also assessed correlates of NMR and compared withdrawal and craving between MDD+ and MDD- smokers.

METHODS

Using baseline data from two clinical trials and propensity score weighting based on sex, race, body mass index, and smoking rate, we compared NMR between MDD+ (N = 279) and MDD- (N = 1575) smokers. We also compared groups on and nicotine withdrawal and craving.

RESULTS

Mean NMR (β = -.02, 95% confidence interval [CI]: -0.05 to 0.01, P = .13) and the distribution of smokers across NMR quartiles (odds ratio [OR] = 0.76, 95% CI: 0.50 to 1.16, P = .21) were similar between MDD+ and MDD- samples. This relationship was not affected by antidepressant medication. In the MDD+ sample, African Americans had significantly lower mean NMR, while older smokers and smokers with lower education had higher mean NMR (Ps < .05). MDD+ smokers had significantly higher withdrawal and craving than MDD- smokers (Ps < .05).

DISCUSSION AND CONCLUSIONS

While variability in NMR may not explain differences in smoking rates between MDD+ and MDD- smokers, MDD+ smokers report increased withdrawal and craving.

SCIENTIFIC SIGNIFICANCE

In this first study to assess NMR among MDD+ smokers, the findings underscore the need to address withdrawal and craving within smoking cessation treatments for those with MDD. (Am J Addict 2021;00:00-00).

Patterns of lapses and recoveries during a quit attempt using varenicline and behavioral counseling among smokers with and without HIV

Addressing tobacco use among HIV+ smokers is a priority. Lack of knowledge about how HIV+ smokers respond to tobacco use treatments limits our ability to effectively treat this population of smokers. Using data from 2 clinical trials that provided 12 weeks of varenicline and behavioral counseling, 1 with smokers with HIV (n = 89) and 1 with smokers without HIV (n = 179), we used mixed logistic regression modeling to compare point-prevalence abstinence rates and adherence to the initial target quit date (TQD) and Cox regression for repeated outcomes to evaluate lapse and recovery dynamics between the groups. Sixty percent of HIV- smokers refrained from smoking at the TQD while only 33% of HIV+ smokers did (odds ratio [OR] = 0.32, 95% CI [0.18, 0.56], p < .001). The point-prevalence abstinence rates at Week 12 were 31% (HIV-) and 28% (HIV+; OR = 0.7, 95% CI [0.42, 1.16], p = .16) and the point prevalence abstinence rates at Week 24 were 22% (HIV-) and 15% (HIV+; OR = 0.87, 95% CI [0.49, 1.57], p = .65). Although there was no interaction between HIV status and lapse risk, χ2(3) < 1, there was a significant interaction for the recovery model, (χ2(3) = 20.4, p < 0.001): as the number of events increased, the time to the next recovery became longer among smokers with HIV, compared to smokers without HIV. Although HIV+ smokers were treated effectively with varenicline, compared to HIV- smokers, they showed significantly lower initial cessation at the TQD and took increasingly longer to recover following lapses. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Evaluation of nicotine patch adherence measurement using self-report and saliva cotinine among abstainers in a smoking cessation trial

BACKGROUND

Adherence to nicotine patches relates to cessation. This is the first study to examine the validity of self-reported nicotine patch adherence relative to saliva cotinine.

METHODS

We used data from 198 clinical trial participants who received 11 weeks of nicotine patches, self-reported patch use, had saliva cotinine 1-week after the start of treatment assessed, and were not smoking when saliva was collected (CO < 6). Self-reported patch adherence was defined as: 3-day (before saliva collection), 7-day (before saliva collection), 3-week use (7 days before, and 14 days after, saliva collection), and 11-week use (7 days before, and 10 weeks after, saliva collection). Analyses, including receiver operating characteristic curves, considered differences in nicotine metabolism. Sensitivity, specificity and positive (PPV) and negative predictive value (NPV) assessed optimal cotinine cut-point for adherence.

RESULTS

Self-reported 7-day (r = 0.13) and 3-week (r = 0.13) patch use marginally correlated with week 1 cotinine (p's = 0.08) but not 3-day or 11-week. Significant area under the curve (AUC) values of 0.67 (95 %CI: 0.55-0.79) and 0.72 (95 %CI: 0.57-0.88) were found using 7-day self-report for the overall sample and for slow metabolizers (p's<0.01), but not for normal metabolizers. Optimal 1-week cotinine cut-points using 7-day self-report were 170 ng/mL (overall) and 184 ng/mL (slow), with sensitivity = 0.56-0.62, specificity = 0.69-0.78, PPV = 0.96-0.97, and NPV = 0.13-0.14.

CONCLUSIONS

Among CO-confirmed abstainers, self-reported patch use and saliva cotinine assessed 1-week into treatment, were modestly correlated and optimal cotinine cut-point differed by rate of nicotine metabolism. Seven-day patch use may be a more valid self-report measure of patch adherence based on cotinine than 3-day, 3-week, or 11-week. Rate of nicotine metabolism may affect this relationship.

Characteristics of us adults attempting tobacco use cessation using e-cigarettes

BACKGROUND

Use of e-cigarettes for tobacco cessation efforts is a growing trend in the United States. However, little is known about the factors that determine the use of e-cigarettes for this specific purpose.

METHODS

This study examined current and former cigarette smokers that reported ever using e-cigarettes. Data were obtained from a 2018 Texas population health assessment survey (n = 569) and weighted to be representative to Texas. A multivariable logistic regression was used to assess the socio-demographic and behavioral correlates of using e-cigarettes for tobacco cessation.

RESULTS

Overall, 41.3% of e-cigarette users reported using them for tobacco cessation. Among ever e-cigarette users, Non-Hispanic blacks (aOR: 0.21; 95% CI, 0.07-0.64), males (aOR: 0.40; 95% CI, 0.20-0.80), and individuals not confident in obtaining health information (aOR: 0.38; 95% CI, 0.15-0.96) were less likely to use e-cigarettes for tobacco use cessation. Conversely, among ever e-cigarette users, odds of using e-cigarettes for tobacco cessation were higher among those who were 35-44 years old (aOR: 3.68, 95% CI: 1.26-10.71), those who received advice to quit smoking from a healthcare professional (aOR: 2.77, 95% CI, 1.36-5.64), and those with more than 5 years since their last routine checkup (aOR: 3.91; 95% CI, 1.23-12.45).

CONCLUSION

Findings from this study suggest that both health behaviors and sociodemographic factors predict use of e-cigarettes for the purpose of tobacco cessation. Furthermore, the relationship between use of e-cigarettes as a cessation device and being advised to quit tobacco use by a healthcare professional calls for additional investigation.

Momentary precipitants connecting stress and smoking lapse during a quit attempt

OBJECTIVE

Most attempts at smoking cessation are unsuccessful, and stress is frequently characterized both as a momentary precipitant of smoking lapse and a predictor of subsequent changes in other key precipitants of lapse. The current study examined longitudinal associations among stress, multiple precipitants of lapse, and lapse among smokers attempting to quit.

METHOD

Ecological momentary assessments (EMAs) were gathered from a multiethnic, gender-balanced sample of 370 adults enrolled in a smoking cessation program. EMAs (N = 32,563) assessed smoking lapse and precipitants of lapse, including stress, negative affect, smoking urge, abstinence self-efficacy, motivation to quit, difficulty concentrating, coping outcome expectancies, and smoking outcome expectancies. A multilevel structural equation model simultaneously estimated within-subject paths from stress to multiple precipitants and subsequent smoking lapse. Indirect effects of stress to smoking lapse through precipitants were computed.

RESULTS

Results indicated that increased stress was significantly associated with all precipitants of lapse, consistent with a greater risk for lapse (i.e., increased negative affect, smoking urge, difficulty concentrating, and smoking outcome expectancies and reduced abstinence self-efficacy, motivation to quit, and coping outcome expectancies). All precipitants were significantly associated with subsequent lapse. Indirect effects indicated that stress was uniquely connected to lapse through negative affect, smoking urge, abstinence self-efficacy, coping outcome expectancies, and smoking outcome expectancies.

CONCLUSIONS

Results of this study highlight the broad importance of stress for smoking lapse during a quit attempt. Smoking cessation programs should pay close attention to the role of stress in exacerbating key precipitants of lapse to improve cessation success rates. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Differences in the rate of nicotine metabolism among smokers with and without HIV

OBJECTIVE

HIV-infected smokers lose more life years to tobacco use than to HIV infection. The nicotine metabolite ratio (NMR), a biomarker of CYP2A6, represents individual variation in the rate at which nicotine is metabolized and is associated with response to smoking cessation treatments. We evaluated whether HIV-infected smokers metabolize nicotine faster than HIV-uninfected smokers, which may contribute to the disproportionate smoking burden and may have important treatment implications.

DESIGN

We analysed baseline data from two clinical trials (NCT01710137; NCT01314001) to compare the NMR in HIV-infected smokers (N = 131) to HIV-uninfected smokers (N = 199).

METHODS

Propensity scores were used to match the groups 2 : 1 on characteristics that influence NMR: sex, race, BMI and smoking rate. Nicotine metabolites were assessed via liquid chromatography-tandem mass spectrometry methods and the ratio of 3-hydroxycotinine:cotinine was used to compute the NMR.

RESULTS

HIV-infected smokers had significantly higher NMR (mean = 0.47, SEM = 0.02) and were more likely to be in the highest NMR quartile compared with HIV-uninfected smokers (mean = 0.34, SEM = 0.02; Ps < 0.001).

CONCLUSION

The higher NMR observed among HIV-infected smokers may partially explain higher smoking rates and lower response to transdermal nicotine therapy. Understanding the mechanisms by which HIV and/or ART contribute to faster nicotine metabolism may guide the use of the NMR to personalize tobacco cessation strategies in this underserved population.

Cancer-Related Risk Perceptions and Beliefs in Texas: Findings from a 2018 Population-Level Survey

BACKGROUND

Cancer beliefs and perceptions of cancer risk affect the cancer continuum. Identifying underlying factors associated with these beliefs and perceptions in Texas can help inform and target prevention efforts.

METHODS

We developed a cancer-focused questionnaire and administered it online to a nonprobability sample of the Texas population. Weighted multivariable logistic regression analysis identified key factors associated with perceptions and beliefs about cancer.

RESULTS

The study population comprised 2,034 respondents (median age, 44.4 years) of diverse ethnicity: 45.5% were non-Hispanic white, 10.6% non-Hispanic black, and 35.7% Hispanic. Self-reported depression was significantly associated with cancer risk perceptions and cancer beliefs. Those indicating frequent and infrequent depression versus no depression were more likely to believe that: (i) compared to other people their age, they were more likely to get cancer in their lifetime [OR, 2.92; 95% confidence interval (CI), 1.95-4.39 and OR, 1.79; 95% CI, 1.17-2.74, respectively]; and (ii) when they think about cancer, they automatically think about death (OR, 2.05; 95% CI, 1.56-2.69 and OR, 1.46; 95% CI, 1.11-1.92, respectively). Frequent depression versus no depression was also associated with agreement that (i) it seems like everything causes cancer (OR, 1.67; 95% CI, 1.26-2.22) and (ii) there is not much one can do to lower one's chance of getting cancer (OR, 1.44; 95% CI, 1.09-1.89). Other predictors for perceived cancer risk and/or cancer beliefs were sex, age, ethnicity/race, being born in the United States, marital status, income, body mass index, and smoking.

CONCLUSIONS

Depression and other predictors are associated with cancer risk perceptions and beliefs in Texas.

IMPACT

Increased attention to reducing depression may improve cancer risk perceptions and beliefs.

Predicting smoking abstinence with biological and self-report measures of adherence to varenicline: Impact on pharmacogenetic trial outcomes

INTRODUCTION

Adherence to pharmacotherapies for tobacco dependence, such as varenicline, is necessary for effective treatment. The relationship between varenicline adherence, determined by commonly used indirect (i.e., self-reported pill counts) and infrequently used direct (i.e., varenicline levels) methods, and abstinence outcomes have not been previously examined, nor has their impact on the outcomes of a genetically randomized clinical trial been assessed.

METHODS

At Week 1 following target quit date, self-reported pill count and salivary varenicline levels were obtained from participants (N = 376) in a smoking cessation clinical trial (NCT01314001). Point-prevalence abstinence was biochemically-verified by salivary cotinine at Week 1 and by exhaled carbon monoxide at Week 1, end-of-treatment, 6 and 12 months following treatment. Blood nicotine metabolite ratio (NMR) was obtained at baseline.

RESULTS

Adherent individuals based on varenicline levels were significantly more likely to be abstinent than non-adherent individuals at Week 1 (odds ratios [ORs] 1.92-3.16, p's≤0.006), end-of-treatment (OR = 2.53, p = .004), and six months following treatment (OR = 2.30, p = .03). In contrast, pill counts did not consistently predict abstinence. Including direct measures of adherence enhanced the association between rate of nicotine metabolism (NMR) and end-of-treatment abstinence; normal metabolizers (NMR ≥ 0.31) were significantly more likely than slow metabolizers (NMR < 0.31) to be abstinent at end-of-treatment (OR = 2.00, p = .005).

CONCLUSION

Adherence based on salivary varenicline, rather than on pill counts, is predictive of Week 1 abstinence, irrespective of the biomarker of abstinence assessed, and of long-term abstinence. Direct measures of adherence enhance the ability to assess the impact of a biomarker or genetic marker on abstinence outcomes.

Measures and predictors of varenicline adherence in the treatment of nicotine dependence

INTRODUCTION

While adherence to medication in smoking cessation clinical trials is strongly associated with clinical outcome, very few studies have evaluated the validity of pill count as a measure of adherence relative to a biological assay, and evaluated a broad range of correlates of adherence.

METHODS

In a smoking cessation clinical trial of varenicline, we compared pill counts collected over 4 different time periods to varenicline salivary levels taken after 2weeks of treatment, as well as evaluated predictors of adherence to varenicline.

RESULTS

Using a binary measure of adherence based on salivary varenicline levels, adherence was higher among older, white, and more educated participants. Relative to 3, 7, and 14-day pill count, 12-week pill count was the only significant measure able to discriminate adherence as defined by salivary varenicline levels (assessed by area under the receiver operating characteristic curve; AUC=0.59, p=0.004). Seventy-two percent of participants who indicated adherence on 12-week pill count were classified as adherent based on varenicline saliva levels (sensitivity=0.80; specificity=0.40). There was modest variability in the relationship between 12-week pill count and varenicline levels across race and rate of nicotine metabolism. Lastly, General Estimating Equation models demonstrated that longitudinal changes in withdrawal, craving, negative and positive affect, and side effect count and severity were not related to adherence based on salivary varenicline levels.

CONCLUSIONS

These results indicate that 12-week pill count was the best, albeit a relatively weak, measure of varenicline adherence; additional factors associated with treatment adherence need to be identified.

Smoking Cessation in Patients With Cancer: Treatment Advances and the Oncologist's Role

The harms of smoking cigarettes are well-known, and the benefits of smoking cessation are well-established. Smoking cessation is especially important for patients with cancer, because smoking compromises the effects of cancer treatment and shortens survival. Interventions to achieve tobacco abstinence include pharmacotherapy and counseling, and these often must be repeated. Patients should be encouraged at every juncture to continue attempts to stop smoking.

Smoking Cessation, Version 1.2016, NCCN Clinical Practice Guidelines in Oncology

Cigarette smoking has been implicated in causing many cancers and cancer deaths. There is mounting evidence indicating that smoking negatively impacts cancer treatment efficacy and overall survival. The NCCN Guidelines for Smoking Cessation have been created to emphasize the importance of smoking cessation and establish an evidence-based standard of care in all patients with cancer. These guidelines provide recommendations to address smoking in patients and outlines behavioral and pharmacologic interventions for smoking cessation throughout the continuum of oncology care.

Racial differences in the relationship between rate of nicotine metabolism and nicotine intake from cigarette smoking

Rate of nicotine metabolism has been identified as an important factor influencing nicotine intake and can be estimated using the nicotine metabolite ratio (NMR), a validated biomarker of CYP2A6 enzyme activity. Individuals who metabolize nicotine faster (higher NMR) may alter their smoking behavior to titrate their nicotine intake in order to maintain similar levels of nicotine in the body compared to slower nicotine metabolizers. There are known racial differences in the rate of nicotine metabolism with African Americans on average having a slower rate of nicotine metabolism compared to Whites. The goal of this study was to determine if there are racial differences in the relationship between rate of nicotine metabolism and measures of nicotine intake assessed using multiple biomarkers of nicotine and tobacco smoke exposure. Using secondary analyses of the screening data collected in a recently completed clinical trial, treatment-seeking African American and White daily smokers (10 or more cigarettes per day) were grouped into NMR quartiles so that the races could be compared at the same NMR, even though the distribution of NMR within race differed. The results indicated that rate of nicotine metabolism was a more important factor influencing nicotine intake in White smokers. Specifically, Whites were more likely to titrate their nicotine intake based on the rate at which they metabolize nicotine. However, this relationship was not found in African Americans. Overall there was a greater step-down, linear type relationship between NMR groups and cotinine or cotinine/cigarette in African Americans, which is consistent with the idea that differences in blood cotinine levels between the African American NMR groups were primarily due to differences in CYP2A6 enzyme activity without titration of nicotine intake among faster nicotine metabolizers.

Bayesian function-on-function regression for multilevel functional data

Medical and public health research increasingly involves the collection of complex and high dimensional data. In particular, functional data-where the unit of observation is a curve or set of curves that are finely sampled over a grid-is frequently obtained. Moreover, researchers often sample multiple curves per person resulting in repeated functional measures. A common question is how to analyze the relationship between two functional variables. We propose a general function-on-function regression model for repeatedly sampled functional data on a fine grid, presenting a simple model as well as a more extensive mixed model framework, and introducing various functional Bayesian inferential procedures that account for multiple testing. We examine these models via simulation and a data analysis with data from a study that used event-related potentials to examine how the brain processes various types of images.

Lack of Associations of CHRNA5-A3-B4 Genetic Variants with Smoking Cessation Treatment Outcomes in Caucasian Smokers despite Associations with Baseline Smoking

CHRNA5-A3-B4 variants, rs16969968, rs588765 and rs578776, are consistently associated with tobacco consumption among smokers, but the association with smoking cessation is less consistent. Among the studies that reported significant associations with cessation, the effects were observed in smokers treated with placebo treatment in some studies and conversely in those receiving active pharmacological therapy (bupropion and nicotine replacement therapies) in others. Thus, it remains unclear whether CHRNA5-A3-B4 is a useful marker for optimizing smoking cessation. Using data from 654 Caucasian smokers treated with placebo, nicotine patch or varenicline, we investigated whether CHRNA5-A3-B4 variants were associated with smoking cessation outcomes, and whether there were significant genotype-by-treatment or haplotype-by-treatment interactions. We observed no significant associations between CHRNA5-A3-B4 variants and smoking cessation, despite replicating previous associations with baseline tobacco consumption. At end of treatment the effect size on smoking cessation in the placebo, patch and varenicline groups for rs16969968 [GG vs. GA+AA] was OR = 0.66 (P = 0.23), OR = 1.01 (P = 0.99), and OR = 1.30 (P = 0.36) respectively, of rs588765 [CC vs. CT+TT] was OR = 0.96 (P = 0.90), OR = 0.84 (P = 0.58), and OR = 0.74 (P = 0.29) respectively, and for rs578776 [GG vs. GA+AA] on smoking cessation was OR = 1.02 (P = 0.95), OR = 0.75 (P = 0.35), and OR = 1.20 (P = 0.51) respectively. Furthermore, we observed no associations with cessation using the CHRNA5-A3-B4 haplotype (constructed using rs16969968 and rs588765), nor did we observe any significant genotype-by-treatment interactions, with or without adjusting for the rate of nicotine metabolism (all P>0.05). We also observed no significant genetic associations with 6 month or 12 month smoking abstinence. In conclusion, we found no association between CHRNA5-A3-B4 variants and smoking cessation rates in this clinical trial; however, as expected, significant associations with baseline tobacco consumption were replicated. Our data suggest that CHRNA5-A3-B4 gene variants do not exhibit a robust association with smoking cessation and are unlikely to be useful for clinically optimizing smoking cessation pharmacotherapy for Caucasian smokers.

Selection of optimal tobacco cessation medication treatment in patients with cancer

BACKGROUND

Tobacco use is responsible for almost half a million deaths per year in the United States, and it accounts for one-third of all cancer deaths. Limited data concerning tobacco treatment among patients with cancer are available. In addition, these patients often have complicated medical histories and are taking multiple medications. No clear, published procedures exist to help the healthcare provider select the proper medication for tobacco cessation in that context.

OBJECTIVES

This article describes the screening process established within the Tobacco Treatment Program (TTP) at the University of Texas MD Anderson Cancer Center to minimize the risk of prescribing a contraindicated tobacco cessation medication to patients with cancer. The screening process developed and used by the TTP is presented as a viable model for selecting appropriate tobacco cessation medications for patients with cancer.

METHODS

The electronic medical record of each patient who uses tobacco is carefully reviewed once he or she is scheduled for a consultation. A summary is produced with a standardized template and used later as a template for the medical provider evaluation. Precautions are put in place with consideration of the characteristics of each of the tobacco cessation medications (e.g., mechanism of action, route of administration, interactions with other medications, possible side effects, contraindications). Since 2006, the TTP has had more than 4,000 new patients and more than 39,000 follow-up visits.

FINDINGS

Because each patient with cancer has unique medical, psychological, and social circumstances, the process of selecting the optimal tobacco cessation medication needs to be individualized. Oncology healthcare providers should follow some form of screening to tailor a medication plan to each patient.

Use of the nicotine metabolite ratio as a genetically informed biomarker of response to nicotine patch or varenicline for smoking cessation: a randomised, double-blind placebo-controlled trial

BACKGROUND

Substantial variability exists in therapeutic response and adverse effects with pharmacotherapies for tobacco dependence. Biomarkers to optimise treatment choice for individual smokers might improve treatment outcomes. We tested whether a genetically informed biomarker of nicotine clearance, the nicotine metabolite ratio (NMR; 3'-hydroxycotinine:cotinine), predicts response to nicotine patch or varenicline for smoking cessation.

METHODS

We undertook NMR-stratified multicentre, randomised, placebo-controlled clinical trial from Nov 16, 2010, to Sept 12, 2014, at four sites. Smokers seeking treatment were randomly assigned by baseline NMR status and study site, in blocks of 12 patients (1:1:1 ratio), to 11 weeks of placebo (placebo pill plus placebo patch), nicotine patch (active patch plus placebo pill), or varenicline (active pill plus placebo patch), plus behavioural counselling. Participants and investigators were masked to group allocation and NMR status. An intention-to-treat analysis was done. Participants were followed up for 12 months after the target quit date. The primary endpoint was biochemically verified 7 day point prevalence abstinence at the end of treatment to estimate the pharmacological effect of treatment by NMR. The trial is registered at ClinicalTrials.gov, number NCT01314001.

FINDINGS

1246 participants (662 slow metabolisers of nicotine, 584 normal metabolisers of nicotine) were enrolled and randomly assigned to the three interventions (408 placebo, 418 nicotine patch, 420 varenicline). At end of treatment, varenicline was more efficacious than nicotine patch in normal metabolisers (OR 2·17, 95% CI 1·38-3·42; p=0·001), but not in slow metabolisers (OR 1·13, 0·74-1·71; p=0·56). In the longitudinal model including all timepoints, the NMR-by-treatment interaction was significant (ratio of odds ratios [ORR] 1·96, 95% CI 1·11-3·46; p=0·02). An NMR-by-treatment interaction showed that slow (vs normal) metabolisers reported greater overall side-effect severity with varenicline versus placebo (β=-1·06, 95% CI -2·08 to -0·03; p=0·044).

INTERPRETATION

Treating normal metabolisers with varenicline and slow metabolisers with nicotine patch could optimise quit rates while minimising side-effects.

FUNDING

National Institutes of Health, Canadian Institutes of Health Research, Abramson Cancer Center, Centre for Addiction and Mental Health Foundation, and Pennsylvania Department of Health.

The relationship between the nicotine metabolite ratio and three self-report measures of nicotine dependence across sex and race

RATIONALE

Variability in the rate of nicotine metabolism, measured by the nicotine metabolite ratio (NMR), is associated with smoking behavior. However, data linking the NMR with nicotine dependence measured by the Fagerström test for nicotine dependence (FTND) are mixed. Few past studies have examined alternative measures of nicotine dependence and how this relationship may vary by sex and race.

OBJECTIVE

Using data from smokers undergoing eligibility evaluation for a smoking cessation clinical trial (n = 833), this study examined variability in the relationship between NMR and nicotine dependence across sex and race and using three measures of nicotine dependence: FTND, time-to-first-cigarette (TTFC), and the heaviness of smoking index (HSI).

RESULTS

Controlling for sex and race, nicotine metabolism was associated with nicotine dependence only when using the HSI (p < 0.05). Male normal metabolizers of nicotine were more likely to have high nicotine dependence based on the FTND and HSI (p < 0.05), but NMR was not related to measures of nicotine dependence in women. For African Americans, the NMR was associated with nicotine dependence only for the TTFC (p < 0.05), but NMR was not associated with nicotine dependence among Caucasians. Post hoc analyses indicated that the NMR was associated with cigarettes per day, overall, and among men and Caucasians (p < 0.05).

CONCLUSIONS

While there was some variation in the relationship between nicotine metabolism and nicotine dependence across measures and sex and race, the results indicate that this relationship may be more attributable to the association between NMR and cigarettes per day.

The role of prepartum motivation in the maintenance of postpartum smoking abstinence

OBJECTIVE

Motivation plays an important role in a variety of behaviors, including smoking cessation, and is integral to theory and treatment of smoking. For many women, pregnancy offers a motivational shift that helps them stop smoking and maintain abstinence during pregnancy. However, women's motivation to maintain smoking abstinence postpartum is not well-understood and may play a role in high postpartum relapse rates. The current study utilized multiple measures of prepartum motivation to maintain smoking abstinence to predict postpartum smoking abstinence.

METHODS

As part of a randomized clinical trial on postpartum smoking relapse prevention, pregnant women who quit smoking during pregnancy reported their motivation to continue smoking abstinence at a prepartum baseline session. Biochemically verified continued smoking abstinence was assessed at 8 and 26 weeks postpartum.

RESULTS

Direct relationships among multiple measures of motivation were significant, and ranged in strength from weak to moderate. All motivation measures individually predicted continuous smoking abstinence, after controlling for treatment group, demographics, and prequit tobacco use. When tested simultaneously, a global motivation measure and parenthood motives for quitting remained significant predictors of abstinence. Backward selection modeling procedures resulted in a reduced model of prepartum predictors of postpartum abstinence including global motivation, parenthood motives, and stage of change.

CONCLUSIONS

Global motivation for smoking abstinence and parenthood motives for quitting are particularly important motivational constructs for pregnant women's continued smoking abstinence.

Chipping away at the genetics of smoking behavior

Three large consortia present comprehensive analyses that identify genetic factors influencing smoking initiation, intensity and cessation. The genetic architecture of these three phases of smoking behavior appears to be largely distinct.

Associations between mindfulness and implicit cognition and self-reported affect

Theory suggests that mindful individuals exhibit enhanced attentional processing (e.g., attentional control) and that they maintain a detached perspective to problematic stimuli. For smokers, smoking and affective stimuli are problematic stimuli when they try to quit. In this cross-sectional study, smokers (n = 158) completed 3 modified Stroop tasks (to assess attentional control), 3 Implicit Association Tests (IATs; to assess detached perspective), and a battery of self-report assessments. Degree of mindfulness was negatively associated (P < .05) with self-reported negative affect, perceived stress, and depressive symptom severity, and positively associated (P < .05) with positive affect. Degree of mindfulness was not associated with the ability to disengage attention from smoking or affective stimuli. On the depression IAT, more mindful participants exhibited a more negative IAT effect, suggesting that they may have developed a detached perspective to depression-related stimuli. Theoretical and clinical implications of the data are discussed.

Associations of mindfulness with nicotine dependence, withdrawal, and agency

Quitting smoking is a major life stressor that results in numerous aversive consequences, including persistently increased level of post-cessation negative affect and relapse. The identification of factors that may enhance behavioral and emotional regulation after quitting may be useful in enhancing quit rates and preventing relapse. One factor broadly linked with behavioral and emotional regulation is mindfulness. This study examined baseline associations of mindfulness with demographic variables, smoking history, dependence, withdrawal severity, and agency among 158 smokers enrolled in a cessation trial. Results indicated that mindfulness was negatively associated with level of nicotine dependence and withdrawal severity, and positively associated with a sense of agency regarding cessation. Moreover, mindfulness remained significantly associated with these measures even after controlling for key demographic variables. Results suggest that low level of mindfulness may be an important predictor of vulnerability to relapse among adult smokers preparing to quit; thus, mindfulness-based interventions may enhance cessation.

The D2 dopamine receptor gene and nicotine dependence among bladder cancer patients and controls

Multiple twin, family, and genetic studies have rendered substantial evidence supporting an association between hereditary factors and smoking initiation and maintenance. To investigate further the relationships between the DRD2 genotypes, cigarette use and nicotine dependence, we examined the prevalence of polymorphisms in the TaqIA (A1 and A2) and the TaqIB (B1 and B2) alleles among a series of 608 non-Hispanic White bladder cancer patients and 608 matched controls. Among ever-smoking controls, A1 and B1 genotypes exhibited a greater smoking intensity and were significantly younger at the age of initiation than A2A2 or B2B2 genotypes (two-sided P < 0.05). Among former smoking cases, persons with the A1 genotypes exhibited significantly higher mean pack-years and years of smoking, and were younger at the age of initiation than were persons with the A2A2 genotype (two-sided P < 0.05). Additionally, current smokers with the A1 genotypes reported fewer quit attempts than those with the A2A2 genotype (two-sided P < 0.01). The present study suggests that the DRD2 alleles A1 and B1 confer greater vulnerability to tobacco use.

A meta-analytic review of the CYP2A6 genotype and smoking behavior

Individuals who carry variant alleles of the CYP2A6 gene are poor metabolizers of nicotine and are believed to be more sensitive to nicotine's aversive effects than those with normal alleles. This sensitivity is hypothesized to exert a protective effect against smoking initiation and lead to lower cigarette consumption among smokers with variant alleles. Although early studies found an association between variant CYP2A6 alleles and smoking behavior, more recent studies have not. A meta-analysis was conducted to help resolve these conflicting results. A literature search produced 11 studies providing information on CYP2A6 genotyping in smokers or nonsmoking control subjects. Participants were classified as smokers (ever-smokers or current smokers) or nonsmokers (former or never-smokers), and as carrying normal CYP2A6 genes or one or more variant alleles. Information regarding cigarette consumption also was included. Effect sizes were calculated from each study and then aggregated into an overall effect size. This analysis failed to find any empirical evidence of a relationship between variant CYP2A6 alleles and smoking status (n=4091) or cigarette consumption (n=1537). Although these results suggest the CYP2A6 gene is not associated with smoking behavior, the use of broad smoking status classifications (e.g., ever- vs. never-smoking), which fail to account for the complex nature of gene expression (e.g., gene-gene interactions), may have obscured the relatively modest genetic influences that might have been present. What role, if any, the CYP2A6 gene plays in smoking behavior will be understood only if future research addresses these methodological concerns.

The effects of the DRD2 polymorphism on smoking cessation and negative affect: Evidence for a pharmacogenetic effect on mood

This study evaluated the relationship between smoking cessation treatment outcome and the DRD2 polymorphism. Participants were 134 smokers who took part in a larger clinical trial evaluating the effects of an antidepressant medication (venlafaxine or placebo) plus standard care (brief counseling and nicotine replacement therapy). Venlafaxine is an antidepressant that inhibits the reuptake of serotonin and norepinephrine. A1 smokers were expected to quit significantly less often on placebo, although the abstinence rates between A1s and A2s on active drug were not expected to differ (i.e., an interaction between genotype and drug was hypothesized). In addition, antidepressant therapy was expected to have a similar genotype x treatment interaction on negative affect reduction. The results showed that smokers carrying the DRD2 A1 allele (A1/A1/A2) quit significantly less often than the homozygous A2s (OR=1.54, 95% CI=1.01-2.36). No interaction with treatment was observed. A significant pharmacogenetic effect of the drug on negative mood while quitting also was noted. Smokers absent the A1 allele (A2/A2) responded to the drug with a substantial reduction in negative affect, whereas those with the A1 allele showed no significant reduction in negative mood, F(1, 130)=5.95, p=.01. These results are contrary to expectations and suggest that although A1s may have more difficulty quitting, adding venlafaxine does not improve abstinence or mood. However, the results for the A2s provide evidence for a genotype-specific response to a pharmacological intervention, which could have implications for the development of future treatments.

Differential mutagen sensitivity of peripheral blood lymphocytes from smokers and nonsmokers: effect of human cytomegalovirus infection

We used the mutagen sensitivity assay to test the hypothesis that human cytomegalovirus (HCMV) infection modifies the sensitivity of cells to genetic damage from genotoxic agents. Chromosome aberration (CA) frequency in peripheral blood lymphocytes (PBLs) from 20 smokers who were matched with 20 nonsmokers by age (+/- 5 years), sex, and ethnicity was evaluated following in vitro exposure to bleomycin and/or HCMV infection. Bleomycin induced significant (P < 0.05) concentration-dependent increases in the frequency of aberrant cells, chromatid-type damage (breaks), and chromosome-type aberrations (deletions, rearrangements) in PBLs. The baseline (background) CA frequency was similar in both smokers and nonsmokers. Significantly higher frequencies of aberrant cells (P < 0.05) were observed in PBLs from smokers compared to nonsmokers at all bleomycin concentrations tested (10, 30 and 100 microg/ml). Infection of PBLs with HCMV induced a significant (P < 0.05) twofold increase in the frequency of CA (primarily chromatid breaks) in PBLs, regardless of the smoking status. PBLs from smokers and nonsmokers infected with HCMV prior to challenge with bleomycin demonstrated significant (P < 0.05) concentration-dependent increases in the levels of aberrant cells, chromatid-type damage (breaks), and chromosome-type aberrations (deletions, rearrangements) compared to noninfected cells challenged with bleomycin. The frequency of induced CA was consistently higher for PBLs derived from smokers relative to nonsmokers (P = 0.06 and 0.002). These data indicate that, individually, both smoking and HCMV infection significantly enhance the sensitivity of PBLs to bleomycin-induced genetic damage. More importantly, the data also suggest that smoking and HCMV infection interact synergistically to enhance the sensitivity of PBLs to such damage.

Case-control study of the D2 dopamine receptor gene and smoking status in lung cancer patients

BACKGROUND

Interindividual differences in the structure and expression of the dopamine receptor genes affect dopamine availability and may be the genetic basis for variation in vulnerability to tobacco smoking. In this study, prevalences of polymorphisms in the TaqIA allele (A1 and A2) and the TaqIB allele (B1 and B2) of the D2 dopamine receptor gene in 157 lung cancer case patients and 126 control subjects were determined to assess whether individuals homozygous or heterozygous for the less common A1 and B1 alleles are more vulnerable to nicotine addiction.

METHODS

Case and control subjects were accrued from an ongoing epidemiologic study. Blood samples were collected from them and subjected to molecular genetic analyses. Subjects were interviewed to obtain relevant information. Current and former smokers were administered a questionnaire to quantify their addiction to nicotine.

RESULTS

The combined B1B2 genotypes appeared to be more prevalent in ever smokers than in never smokers among case patients (30.3% versus 13.3%; two-sided P = .233) and among control subjects (30.9% and 0%; two-sided P = .02); statistically significant differences were not observed among those with A1 genotypes. Statistically significant correlations between the presence of the A1 and B1 alleles were observed (r = .73 for case subjects and r = .76 for control subjects; two-sided P<.001). Individuals with rarer genotypes reported having been substantially younger at the time of smoking initiation (statistically significant for both A1 and B1) and having attempted to quit smoking fewer times (statistically significant for only A1).

CONCLUSION

Variant alleles of the D2 dopamine receptor gene may play a role in determining nicotine addiction, although the associations between the at-risk genotypes and measures of nicotine addiction were not entirely consistent.

Current approaches in smoking cessation

This review highlights the necessity of smoking cessation as a cornerstone of cancer prevention. We briefly review the literature linking smoking to various forms of cancer, the benefits of smoking cessation for cancer patients, and the Agency for Health Care Policy and Research Smoking Cessation Clinical Practice Guideline. Also provided is an update on controlled smoking cessation studies published between March 1995 and February 1996.