Cigarette smoking prevalence, cessation and relapse

Event-related potentials reflecting smoking cue reactivity and cognitive control as predictors of smoking relapse and resumption

RATIONALE

Given that most attempts to quit smoking fail, it is critical to increase knowledge about the mechanisms involved in smoking relapse and resumption (i.e., the increase in smoking over time after a quit attempt). Neurocognitive measures, such as event-related potentials (ERPs), may provide novel insights into smoking relapse and resumption.

OBJECTIVES

The objective of the present study is to investigate the association between smoking relapse and resumption and ERPs reflecting smoking cue reactivity (i.e., P300, LPP), inhibitory control (i.e., N2, P3), and error processing (i.e., error-related negativity (ERN), Pe).

METHODS

Seventy-two smokers viewed smoking and neutral pictures and performed a Go-NoGo and an Eriksen Flanker task, while ERPs were measured using electroencephalography. All smokers started a quit attempt in the week following the laboratory visit. Smoking behavior after the quit attempt was measured at 4, 8, and 12 weeks. Both relapse (i.e., 7-day point prevalence at 12 weeks) and smoking resumption (i.e., the number of cigarettes a day at 4, 8, and 12 weeks) were used as outcome measures.

RESULTS

Logistic regression analyses showed that smaller P3 amplitudes, reflecting brain activation associated with inhibitory control, are related to an increased relapse risk. Latent growth curve analyses showed that reduced post-error slowing, the main behavioral measure reflecting error processing, is associated with stronger smoking resumption. ERPs reflecting smoking cue reactivity were unrelated to smoking relapse or resumption.

CONCLUSIONS

The finding that smaller inhibitory control-related P3 amplitudes are associated with increased relapse risks suggests that strategies to increase inhibitory control in smokers are worth further investigation in the search for more effective smoking cessation interventions.

Le craving comme symptôme central de la toxicomanie : de ses fondements neurobiologiques à sa pertinence clinique

Le craving, ce désir intense de consommer, est un symptôme central de la toxicomanie. Jusqu’au début des années 2000, peu d’outils existaient afin d’étudier le phénomène de manière plus concrète pour mieux le définir, le comprendre et approfondir les fondements neurobiologiques qui le sous-tendent. Avec les avancées technologiques des dernières années (IRM fonctionnelle, PET Scan), puis l’arrivée du DSM-V et son inclusion comme critère diagnostique des troubles liés à l’utilisation de substances, le craving est devenu un symptôme central en toxicomanie. Sa définition a évolué et est de plus en plus précise à plusieurs égards. Nous avons une meilleure compréhension des voies neurobiologiques impliquées dans le phénomène ainsi qu’une meilleure compréhension des facteurs capables de le déclencher. Finalement, plusieurs travaux ont évoqué le rôle du craving dans la rechute lors de l’abstinence, et quelques traitements pharmacologiques se sont démontrés efficaces afin d’atténuer ce symptôme et éviter la rechute. Le craving s’avère ainsi une cible de choix afin de trouver de nouvelles avenues thérapeutiques pour briser le cycle de la dépendance.

Changes in success rates of smoking cessation treatment associated with take up of a national evidencebased training programme

OBJECTIVE

The English 'stop smoking services' provide behavioural support to some 700,000 smokers annually. Success rates of the services varied considerably before 2010 and had been in slight decline so, to improve performance, a national programme of evidence-based practitioner training was developed to improve knowledge and skills-based competences. This study evaluated whether uptake of the training was associated with improvements in success rates of services.

METHODS

Mean 4-week biochemically verified abstinence rates were compared for 146 (of 151) stop smoking services between 2008-10 (before roll-out of training) and 2011-13 (after roll-out), and the change in success rates for each service was regressed on to the number of practitioners per service trained in a) knowledge (online) and b) skills (face-to-face).

RESULTS

Success rate across all services improved between the two periods (34.1% to 36.5%, p=0.01 1-tailed; 95% CI for difference 0.44-4.48). The magnitude of improvement for each service was associated with the number of practitioners who completed the knowledge and skills training (beta=0.22, p=0.005 1-tailed), and marginally with the number who completed the knowledge training (beta=0.14, p=0.047 1-tailed).

CONCLUSION

English stop smoking services that have greater uptake of a national evidence-based training programme showed greater improvements in success rates.

Association between nicotine replacement therapy use in pregnancy and smoking cessation

BACKGROUND

There is an urgent need to find better ways of helping pregnant smokers to stop. Randomized controlled trials (RCTs) have not detected an effect of nicotine replacement therapy (NRT) for smoking cessation in pregnancy. This may be because of inadequate dosing because of faster nicotine metabolism in this group. In England, many pregnant smokers use single form and combination NRT (patch plus a faster acting form). This correlational study examined whether the latter is associated with higher quit rates.

METHODS

Routinely collected data from 3880 pregnant smokers attempting to stop in one of 44 Stop Smoking Services in England. The outcome measure was 4-week quit rates, verified by expired-air carbon monoxide level<10 ppm. Outcome was compared between those not using medication versus using single form NRT (patch or one of the faster acting forms), or combination NRT. Potential confounders were intervention setting (specialist clinic, home visit, primary care, other), intervention type (one-to-one, group, drop-in, other), months pregnant, age, ethnicity and occupational group in multi-level logistic regressions.

RESULTS

After adjustment, combination NRT was associated with higher odds of quitting compared with no medication (OR=1.93, 95% CI=1.13-3.29, p=0.016), whereas single NRT showed no benefit (OR=1.06, 95% CI=0.60-1.86, p=0.84).

CONCLUSIONS

Use of a combination of nicotine patch and a faster acting form may confer a benefit in terms of promoting smoking cessation during pregnancy. While this conclusion is based on correlational data, it lends support to continuing this treatment option pending confirmation by an RCT.

The cost-effectiveness of smoking cessation support delivered by mobile phone text messaging: Txt2stop

BACKGROUND

The txt2stop trial has shown that mobile-phone-based smoking cessation support doubles biochemically validated quitting at 6 months. This study examines the cost-effectiveness of smoking cessation support delivered by mobile phone text messaging.

METHODS

The lifetime incremental costs and benefits of adding text-based support to current practice are estimated from a UK NHS perspective using a Markov model. The cost-effectiveness was measured in terms of cost per quitter, cost per life year gained and cost per QALY gained. As in previous studies, smokers are assumed to face a higher risk of experiencing the following five diseases: lung cancer, stroke, myocardial infarction, chronic obstructive pulmonary disease, and coronary heart disease (i.e. the main fatal or disabling, but by no means the only, adverse effects of prolonged smoking). The treatment costs and health state values associated with these diseases were identified from the literature. The analysis was based on the age and gender distribution observed in the txt2stop trial. Effectiveness and cost parameters were varied in deterministic sensitivity analyses, and a probabilistic sensitivity analysis was also performed.

FINDINGS

The cost of text-based support per 1,000 enrolled smokers is £16,120, which, given an estimated 58 additional quitters at 6 months, equates to £278 per quitter. However, when the future NHS costs saved (as a result of reduced smoking) are included, text-based support would be cost saving. It is estimated that 18 LYs are gained per 1,000 smokers (0.3 LYs per quitter) receiving text-based support, and 29 QALYs are gained (0.5 QALYs per quitter). The deterministic sensitivity analysis indicated that changes in individual model parameters did not alter the conclusion that this is a cost-effective intervention. Similarly, the probabilistic sensitivity analysis indicated a >90 % chance that the intervention will be cost saving.

INTERPRETATION

This study shows that under a wide variety of conditions, personalised smoking cessation advice and support by mobile phone message is both beneficial for health and cost saving to a health system.

How does rate of smoking cessation vary by age, gender and social grade? Findings from a population survey in England

AIMS

To assess the incidence of long-term smoking cessation as a function of age, gender, social grade and their interactions.

DESIGN AND SETTING

Cross-sectional surveys of population representative samples of smokers in England.

PARTICIPANTS

A total of 24 094 ever smokers (≥21 and ≤60 years of age) participating in household surveys between November 2006 and February 2011.

MEASUREMENTS

The ratio of long-term (>1 year) ex-smokers to ever-smokers was calculated for each age. Regression analyses were used to model the association between age and quit ratio, with the change in quit ratio by year of age n years versus all years up to n-1 years, yielding an estimate of the quitting incidence at that age. Analyses were conducted for the entire sample and then for the sample stratified by gender and social grade, and interactions assessed between these variables.

FINDINGS

A cubic trend was needed to fit the data. The estimated quitting incidence between ages 21 and 30 was 1.5% (95% CI: 1.0%-2.0%), between 31 and 50 it was 0.3% (95% CI: 0.2%-0.5%) and between 51 and 60 it was 1.2% (95% CI: 0.7%-1.7%). Age interacted with gender and social grade: women and smokers from higher social grades had a higher incidence of quitting than men and those from lower social grades specifically in young adulthood. CONCLUSIONS : The incidence of smoking cessation in England appears to be greater in young and old adults compared with those in middle age. Women and higher social grade smokers show a greater incidence of quitting than men and those from lower social grades specifically in young adulthood.

Urge to smoke over 52 weeks of abstinence

RATIONALE

Cigarette cravings are well documented during the first weeks of smoking abstinence. Treatments focus on helping smokers reduce these acute cravings. Cravings experienced later on are less well understood and may be important when considering treatment duration.

OBJECTIVE

We conducted a longitudinal study of cravings over 52 weeks of smoking abstinence.

METHODS

Cravings were operationalised as strength of, and time spent with, urges to smoke. These were assessed among 452 smokers quitting with behavioural support but without pharmacotherapies. Individuals maintaining abstinence were assessed at 1, 2, 3, 4, 26 and 52 weeks after quitting (n = 197, 156, 139, 131, 66 and 38, respectively). Abstinence was validated at each assessment by expired carbon monoxide. Time courses were plotted for those abstinent for 52 weeks and for those abstinent up to earlier time points. Correlations were examined between ratings of urges at consecutive time points.

RESULTS

Ratings of strength of urges to smoke followed an exponential decline over 52 weeks of abstinence, but 6 months after quitting 13 % of ex-smokers still reported strong urges. At 12 months, no ex-smokers reported strong urges, although 34 % reported some urges. Strength of urges to smoke after 1, 2, 3 and 4 weeks of abstinence predicted strength of urges at 6 months.

CONCLUSIONS

Strength of urges to smoke decline exponentially over time following smoking cessation, though some smokers report strong urges after 6 months of abstinence, and urges are still reported by a third of smokers after 12 months. Relapse prevention treatments may need to target prolonged craving.

Physical activity as an aid to smoking cessation during pregnancy (LEAP) trial: study protocol for a randomized controlled trial

BACKGROUND

Many women try to stop smoking in pregnancy but fail. One difficulty is that there is insufficient evidence that medications for smoking cessation are effective and safe in pregnancy and thus many women prefer to avoid these. Physical activity (PA) interventions may assist cessation; however, trials examining these interventions have been too small to detect or exclude plausible beneficial effects. The London Exercise And Pregnant smokers (LEAP) trial is investigating whether a PA intervention is effective and cost-effective when used for smoking cessation by pregnant women, and will be the largest study of its kind to date.

METHODS/DESIGN

The LEAP study is a pragmatic, multi-center, two-arm, randomized, controlled trial that will target pregnant women who smoke at least one cigarette a day (and at least five cigarettes a day before pregnancy), and are between 10 and 24 weeks pregnant. Eligible patients are individually randomized to either usual care (that is, behavioral support for smoking cessation) or usual care plus a intervention (entailing supervised exercise on a treadmill plus PA consultations). The primary outcome of the trial is self-reported and biochemically validated continuous abstinence from smoking between a specified quit date and the end of pregnancy. The secondary outcomes, measured at 1 and 4 weeks after the quit date, and at the end of pregnancy and 6 months after childbirth, are PA levels, depression, self-confidence, and cigarette withdrawal symptoms. Smoking status will also be self-reported at 6 months after childbirth. In addition, perinatal measures will be collected, including antenatal complications, duration of labor, mode of delivery, and birth and placental weight. Outcomes will be analyzed on an intention-to-treat basis, and logistic regression models used to compare treatment effects on the primary outcome.

DISCUSSION

This trial will assess whether a PA intervention is effective when used for smoking cessation during pregnancy.

TRIAL REGISTRATION

ISRCTN48600346.

Predictors of attempts to stop smoking and their success in adult general population samples: a systematic review

AIMS

To identify the predictors of attempts to stop smoking and the predictors of quit attempt success in adult general population samples.

METHODS

We performed an electronic search of EMBASE, Pubmed, Web of Science, PsychINFO and the Cochrane Tobacco Addiction Group specialized register for articles that examined, in prospective adult general population samples, predictors of quit attempts and the success of quit attempts. Experts were contacted for knowledge of other relevant studies. Eight studies met the inclusion criteria and results were extracted independently by two researchers.

RESULTS

There was considerable methodological heterogeneity between studies. Motivational factors dominated the prediction of quit attempts, whereas only cigarette dependence consistently predicted success after an attempt had been made. Social grade also appeared to predict success but was only examined in two studies. None of the other socio-demographic factors consistently predicted making a quit attempt or success.

CONCLUSIONS

Population-level studies from a number of countries show that past quit attempts and measures of motivation to stop are highly predictive of quit attempts, whereas only measures of dependence are consistently predictive of success of those attempts. Gender, age and marital status and educational level are not related consistently to quit attempts or quit success across countries.

Treating heavy smokers in primary care with the nicotine nasal spray: randomized placebo-controlled trial

AIMS

Of six established nicotine replacement therapy (NRT) formulations, only the gum and patch have been tested without specialist clinic support in placebo-controlled trials. We aimed to broaden the evidence base by examining if the nicotine nasal spray (NNS) could be effective with only brief support in general practice.

DESIGN

Randomized placebo-controlled trial.

SETTING

Twenty-seven English general practices.

PARTICIPANTS

A total of 761 heavy smokers received brief support and 12 weeks of treatment with NNS (506) or placebo (255).

MEASUREMENTS

The primary outcome was biochemically verified complete abstinence from smoking throughout weeks 3-12.

FINDINGS

NNS compared with placebo more than doubled the number who successfully stopped smoking [15.4% versus 6.7%, odds ratio (OR) = 2.6, 95% confidence interval (CI) = 1.5-4.4]. Many participants reported minor irritant adverse symptoms. NNS was particularly effective among those who were more highly dependent on nicotine (OR = 6.17, 95% CI = 2.13-17.9). Of those who failed to stop during the first week (417, 54.8%), only one (0.2%) achieved later success.

CONCLUSIONS

NNS is effective when given in primary care. The benefit was lower than in a specialist clinic but similar to that with the nicotine patch in primary care. Unlike most other NRT formulations, bupropion or varenicline, NNS was especially helpful for more dependent smokers. Continuing treatment of those initially failing was not beneficial. An initial 1-week prescription to those more dependent on nicotine is likely to be the most cost-effective NNS treatment protocol. These results should offer support to the effectiveness of the other NRT formulations untested in this setting.

Rapid reduction versus abrupt quitting for smokers who want to stop soon: a randomised controlled non-inferiority trial

Background

The standard way to stop smoking is to stop abruptly on a quit day with no prior reduction in consumption of cigarettes. Many smokers feel that reduction is natural and if reduction programmes were offered, many more might take up treatment. Few trials of reduction versus abrupt cessation have been completed. Most are small, do not use pharmacotherapy, and do not meet the standards necessary to obtain a marketing authorisation for a pharmacotherapy.

Design/Methods

We will conduct a non-inferiority randomised trial of rapid reduction versus standard abrupt cessation among smokers who want to stop smoking. In the reduction arm, participants will be advised to reduce smoking consumption by half in the first week and to 25% of baseline in the second, leading up to a quit day at which participants will stop smoking completely. This will be assisted by nicotine patches and an acute form of nicotine replacement therapy. In the abrupt arm participants will use nicotine patches only, whilst smoking as normal, for two weeks prior to a quit day, at which they will also stop smoking completely. Smokers in either arm will have standard withdrawal orientated behavioural support programme with a combination of nicotine patches and acute nicotine replacement therapy post-cessation.

Outcomes/Follow-up

The primary outcome of interest will be prolonged abstinence from smoking, with secondary trial outcomes of point prevalence, urges to smoke and withdrawal symptoms. Follow up will take place at 4 weeks, 8 weeks and 6 months post-quit day.

Trial Registration

Current Controlled Trials ISRCTN22526020

Smoking Cessation Pharmacotherapy?Nicotine and Non-Nicotine Preparations

Cigarette smokers tend to die prematurely from a number of diseases. Cigarette smoking is an important modifiable risk factor for cardiovascular morbidity and mortality. Despite the clear health benefits of smoking cessation, smokers usually find it difficult to stop and behavioral therapies often prove insufficient. Pharmacologic intervention may aid the process because of the addictive nature of nicotine. Nicotine replacement therapy, which is regarded as first-line therapy, was developed to overcome the symptoms of nicotine withdrawal that many patients find distressing. Different modes of administration include inhalation and buccal or transdermal absorption. The orally administered non-nicotine drugs varenicline and bupropion are also regarded as first-line treatments, either used alone or as an adjunct to nicotine replacement therapy. Second-line treatments include clonidine and nortriptyline. Other treatment strategies that have been examined include monoamine oxidase inhibitors and selective serotonin reuptake inhibitors; efficacy has yet to be proven definitively. A novel approach to treatment using the cannabinoid-1 receptor antagonist rimonabant is also under investigation.

Chemoprevention of head and neck cancer

Cancer of the aerodigestive tract is associated with great morbidity and mortality in the United States and worldwide. Despite substantial improvements in the delivery of cytotoxic drugs and ionizing radiation therapies, which have resulted in better treatment outcomes, mortality from head and neck malignancies has changed minimally over the last fifty years. Furthermore, the long-term untoward consequences of treatment are significant. Based on this, prevention emerges as a very attractive strategy. Primary prevention through the avoidance of major risk factors, (eg, smoking and ethanol consumption) would result in substantial gains. Unfortunately, behavioral modification (eg, smoking cessation) is not easy to achieve and/or sustain, and even when attained, the carcinogenic risk does not seem to return to that of an individual who never smoked. Chemoprevention is a modality in which compounds are administered singly or in combination to individuals at increased carcinogenic risk in order to halt, prevent, or delay the onset of invasive cancer. This article will review the current status of chemoprevention of the upper aerodigestive tract (UADT), including its biologic basis, clinical models to test for chemopreventive efficacy, and some of the promising strategies that have completed clinical testing or are currently under investigation. Future prospects in the field will also be discussed.

Genetic influence on cigarette-induced cardiovascular disease

Cigarette smoking as an addictive habit has accompanied human beings for more than 4 centuries. It is also one of the most potent and prevalent environmental health risks human beings are exposed to, and it is responsible for more than 1000 deaths each day in the United States. With recent research progress, it becomes clear that cigarette smoking can cause almost all major diseases prevalent today, such as cancer or heart disease. These detrimental effects are not only present in active smokers who choose the risk, but also to innocent bystanders, as passive smokers, who are exposed to cigarettes not-by-choice. While the cigarette-induced harm to human health is indiscriminate and severe, the degree of damage also varies from individual to individual. This intersubject variability in cigarette-induced pathologies is partly mediated by genetic variants of genes that may participate in detoxification process, eg, cytochrome P450 (CYP), cellular susceptibility to toxins, such as p53, or disease development. Through population studies, we have learned that certain CYP1A1 variants, such as Mspl polymorphism, may render the carriers more susceptible to cigarette-induced lung cancer or severe coronary atherosclerosis. The endothelial nitric oxide synthase intron 4 rare allele homozygotes are more likely to have myocardial infarction if they also smoke. In vitro experimental approach has further demonstrated that cigarettes may specifically regulate these genes in genotype-dependent fashion. While we still know little about genetic basis and molecular pathways for cigarette-induced pathological changes, understanding these mechanisms will be of great value in designing strategies to further reduce smoking in targeted populations, and to implement more effective measures in prevention and treatment of cigarette-induced diseases.

Cigarette smoking and rheumatoid arthritis

OBJECTIVES

To examine and explore the potential relationships among the following: the incidence/severity of rheumatoid arthritis (RA), the extra-articular manifestations of RA, vascular disease, certain specific malignancies, the p53 tumor suppressor gene, and cigarette smoking.

METHODS

The medical literature was reviewed from 1985 to 2001 with the assistance of a MEDLINE search using the key words vascular disease, smoking, protein p53, RA, rheumatoid vasculitis, cancer, and malignancies. A qualitative review was performed after all articles were abstracted and new information summarized.

RESULTS

Cigarette smoking has been increasingly shown in epidemiologic and case-control studies to be an important risk factor for both the incidence and severity of RA, especially in seropositive men. Further, there is evidence of a downward trend in incidence of extra-articular manifestations of RA, especially RA vasculitis, observed with a decrease in worldwide tobacco use and overall improved mortality in RA. The association of cigarette smoking with lung and other cancers and its link to vascular disease (including Buerger's disease) and atherosclerosis appears secure. Mutations or alterations in p53, a suppressor gene that regulates cell growth, have been found in certain cancers, cigarette smokers, and in patients with RA.

CONCLUSIONS

Cigarette smoking appears to have an undeniable link to the pathogenesis of vascular disease of many types, including the possibility of a strong causal connection to rheumatoid vasculitis. The observations worldwide of decreasing tobacco use along with secular trends of diminished RA vasculitis and extra-articular manifestations, and with improved survival, points to a better outcome for our patients. The example of p53 may be a first step in the discovery of additional links between environmental triggers and phenotypic expression of chronic illness.

Predictors of smoking reduction and cessation in a cohort of danish moderate and heavy smokers

BACKGROUND

The aim of this study was to examine the extent and gender distribution of unassisted tobacco reduction and cessation in a cohort of moderate and heavy smokers and to identify possible predictor variables associated with these changes in smoking behavior.

METHODS

This was a prospective population study of 3,791 moderate and heavy smokers, 15 g tobacco/day or more, who were enrolled in the Copenhagen City Heart Study in 1976-1978 and attended a reexamination 5 years later. Data on smoking behavior were collected at baseline and follow-up. Smoking reduction was defined as a decrease in mean daily tobacco consumption of 10 g or more. Using multivariate logistic regression, subjects who reported reduced smoking or who reported smoking cessation were compared with subjects who continued the habit unchanged.

RESULTS

After 5 years 13% of the men and 9% of the women had reduced their tobacco consumption, and 9 and 7%, respectively, had quit altogether. Smoking reduction was strongly associated with high tobacco consumption (25+ g/day) at baseline and also with severely impaired lung function (FEV(1) <50% predicted) and overweight (BMI >25). Predictors of smoking cessation included impaired lung function and a tobacco consumption of 15-24 g/day. Additional determinants of smoking reduction and cessation such as inhalation habits and sociodemographic variables differed by gender.

CONCLUSIONS

Several predictors of smoking reduction and cessation were identified, indicating that these subgroups of smokers differ substantially from continuing smokers. This should be taken into account when assessing potential health benefits from these changes in smoking behavior.