Electrocardiographic Changes Associated with Smoking and Smoking Cessation: Outcomes from a Randomized Controlled Trial

Introduction

Cardiovascular disease (CVD) can be detected and quantified by analysis of the electrocardiogram (ECG); however the effects of smoking and smoking cessation on the ECG have not been characterized.

Methods

Standard 12-lead ECGs were performed at baseline and 3 years after subjects enrolled in a prospective, randomized, placebo-controlled clinical trial of smoking cessation pharmacotherapies. ECGs were interpreted using the Minnesota Code ECG Classification. The effects of (i) smoking burden on the prevalence of ECG findings at baseline, and (ii) smoking and smoking cessation on ECG changes after 3 years were investigated by multivariable and multinomial regression analyses.

Results

At baseline, 532 smokers were (mean [SD]) 43.3 (11.5) years old, smoked 20.6 (7.9) cigarettes/day, with a smoking burden of 26.7 (18.6) pack-years. Major and minor ECG criteria were identified in 87 (16.4%) and 131 (24.6%) of subjects, respectively. After adjusting for demographic data and known CVD risk factors, higher pack-years was associated with major ECG abnormalities (p = 0.02), but current cigarettes/day (p = 0.23) was not. After 3 years, 42.9% of subjects were abstinent from smoking. New major and minor ECG criteria were observed in 7.2% and 15.6% of subjects respectively, but in similar numbers of abstinent subjects and continuing smokers (p>0.2 for both). Continuing smokers showed significant reduction in current smoking (–8.4 [8.8] cigarettes/day, p<0.001) compared to baseline.

Conclusions

In conclusion, major ECG abnormalities are independently associated with lifetime smoking burden. After 3 years, smoking cessation was not associated with a decrease in ECG abnormalities, although cigarettes smoked/day decreased among continuing smokers.     

The Prevalence of and Factors Associated with Current Smoking among College of Health Sciences Students,Mekelle University in Northern Ethiopia

Background

Tobacco smoking is one of the greatest causes of preventable morbidity and mortality globally, and is responsible for many causes of untimely deaths. This survey was aimed to determine prevalence and factors associated with current smoking among the students of College of Health Sciences, Mekelle University, Ethiopia.

Methods

A cross-sectional study was employed using a structured self-administered questionnaire among College of Health Sciences students in March 2013. A stratified random sampling method was employed to select study participants. Data were entered and analysed using of Statistical Package for Social Sciences (SPSS) version 20.0.

Results

Of the 193 students, 57 (29.5%) of the students were current smokers. Most of the current smokers (89.4%) smoked between 1–10 sticks of cigarette per day. The two main reasons cited for smoking cigarettes were peer pressure (43.9%) and to relieve stress (36.8%). Being female (adjusted OR [AOR] = 0.49; 95% CI: 0.25, 0.95) and Tigre by ethnicity (AOR = 0.32; 95% CI: 0.14, 0.74) were significantly less associated with current smoking. On the other hand, being second year students (AOR = 3.84; 95% CI: 1.41, 10.46), khat chewing (AOR = 8.36; 95% CI: 2.60, 26.85) and taking illicit drugs (AOR = 10.59; 95% CI: 2.77, 40.51) were positively associated with current smoking cigarettes.

Conclusions

The current smoking prevalence among students in College of Health Sciences, Mekelle University is high and therefore, effective smoking prevention and cessation intervention programs are required to reduce smoking among university students.     

Intention to Switch to Smokeless Tobacco Use among South African Smokers: Results from the 2007 South African Social Attitudes Survey

Background

Some smokeless tobacco products (SLT) have been shown to be associated with only a fraction of the risks of cigarettes. This study assessed South African smokers’ interest in switching to a hypothetical reduced harm SLT product.

Methods

The 2007 South African Social Attitudes Survey was analysed for 678 exclusive cigarette smokers. Respondents were asked about their perceptions about relative harm of snuff compared to cigarettes, and their interest in switching to snuff if informed it was 99% less harmful than cigarettes.

Results

About 49.7% of exclusive cigarette smokers believed that snuff was equally as harmful as cigarettes; 12.9% thought snuff was more harmful; 5.7% thought snuff was less harmful; while 31.8% did not know if there was a difference in harm between snuff and cigarettes. Approximately 24.2% of exclusive cigarette smokers indicated interest in switching to snuff, with significantly greater interest observed among those exposed to 100% smoke-free work environment. Interest in switching was highest (34.7%) among smokers who believed a priori that using snuff was more harmful than cigarettes, and lowest (14.5%) among those who did not know if there was a difference in harm. In a multi-variable adjusted logistic regression model, this latter group remained less likely to be interested in harm reduction switching (adjusted odds ratio = 0.42; 95% CI: 0.19–0.91).

Conclusion

About a quarter of smokers indicated interest in harm reduction switching to snuff. SLT products have a potential role in reducing the harm from smoking in South Africa, but only if they are not used to circumvent smoke-free laws that have been associated with reduced smoking.     

Impact of Cardiovascular Calcifications on the Detrimental Effect of Continued Smoking on Cardiovascular Risk in Male Lung Cancer Screening Participants

Background

Current smokers have an increased cardiovascular disease (CVD) risk compared to ex-smokers due to reversible as well as irreversible effects of smoking. We investigated if current smokers remain to have an increased CVD risk compared to ex-smokers in subjects with a long and intense smoking history. We in addition studied if the effect of smoking continuation on CVD risk is independent of or modified by the presence of cardiovascular calcifications.

Methods

The cohort used comprised a sample of 3559 male lung cancer screening trial participants. We conducted a case-cohort study using all CVD cases and a random sample of 10% (n = 341) from the baseline cohort (subcohort). A weighted Cox proportional hazards model was used to estimate the hazard ratios for current smoking status in relation to CVD events.

Results

During a median follow-up of 2.6 years (max. 3.7 years), 263 fatal and non-fatal cardiovascular events (cases) were identified. Age, packyears and cardiovascular calcification adjusted hazard ratio of current smokers compared to former smokers was 1.33 (95% confidence interval 1.00–1.77). In additional analyses that incorporated multiplicative interaction terms, neither coronary nor aortic calcifications modified the association between smoking status and cardiovascular risk (P = 0.08).

Conclusions

Current smokers have an increased CVD risk compared to former smokers even in subjects with a long and intense smoking history. Smoking exerts its hazardous effects on CVD risk by pathways partly independent of cardiovascular calcifications.     

Smoking Cessation Increases Short-Term Risk of Type 2 Diabetes Irrespective of Weight Gain: The Japan Public Health Center-Based Prospective Study

Objective

The effect of smoking cessation on the risk of diabetes has been reported previously. However, it is unknown whether the association is influenced by weight gain and other potential risk factors.

Methods

The Japan Public Health Center-Based Prospective Study established in 1990 for Cohort I and in 1993 for Cohort II provided data, and 25,875 men and 33,959 women were analyzed. The response rate to the baseline questionnaire was 80.9%, and 68.4% of the respondents participated both the 5- and 10-year follow-up surveys. Smoking cessation was noted during the initial five years and the development of diabetes was reported in the subsequent five years.

Results

An increased risk was observed among individuals who newly quit smoking compared with never smokers among men (odds ratio (OR) = 1.42, 95% CI = 1.03–1.94) and women (OR = 2.84, CI = 1.53–5.29). The risk of developing diabetes among male new quitters who gained 3 kg or more during the 5-year follow-up did not substantially differ from the risk among male never smokers with less than 3 kg of weight gain or no weight gain, while an increased risk was observed among male new quitters with less or no weight gain (OR = 1.46, 95%CI 1.00–2.14). An insignificant increased risk was observed among male new quitters with a family history of diabetes compared with male never smokers with a family history of diabetes. The risk was more than twice as high for male new quitters who used to smoke 25 or more cigarettes per day compared with never smokers (OR = 2.15, 95%CI: 1.34–3.47).

Discussion

An increased risk of diabetes was implied among individuals who quit smoking. However, the increased risk was not implied among those who gained weight over the 5-years of follow-up. Those who had major risk factors for diabetes or who smoked heavier had a higher risk.     

Stressful Events and Continued Smoking and Continued Alcohol Consumption during Mid-Pregnancy

Aim

to examine whether the severity of different categories of stressful events is associated with continued smoking and alcohol consumption during mid-pregnancy. Also, we explored the explanation of these associations by anxiety and depressive symptoms during pregnancy. Finally, we studied whether the severity of stressful events was associated with the amount of cigarettes and alcohol used by continued users.

Method

we conducted a cross-sectional analysis using data from a population-based prospective cohort study. Pregnant women were recruited via midwifery practices throughout The Netherlands. We analyzed women who continued smoking (n = 113) or quit (n = 290), and women who continued alcohol consumption (n = 124) or quit (n = 1403) during pregnancy. Smoking, alcohol consumption, and perceived severity of stressful events were measured at 19 weeks of gestation. The State Trait Anxiety Inventory and the Edinburgh Postnatal Depression Scale were filled out at 14 weeks of gestation. Odds ratios were calculated as association measures and indicated the relative increase for the odds of continuation of smoking and alcohol consumption for the maximum severity score compared to the minimum score.

Findings

severity of the following stressful event categories was associated with continued alcohol consumption: ‘conflict with loved ones’ (OR = 10.4, p<0.01), ‘crime related’ (OR = 35.7, p<0.05), ‘pregnancy-specific’ (OR = 13.4, p<0.05), and the total including all events (OR = 17.2, p<0.05). Adjustment for potential confounders (age, parity and educational level) did not notably change the estimates. There was no association of anxiety and depressive symptoms with continued smoking or alcohol consumption. No associations emerged for continued smoking and severity of stressful events. The amount of cigarettes and alcohol consumption among continued users was not associated with severity of stressful events.

Conclusions

Our findings may be relevant for health care providers, in particular midwives and general practitioners. The impact of stressful events may be considered when advising pregnant women on smoking and alcohol consumption.     

Effects of smoking and cessation on subclinical arterial disease: a substudy of a randomized controlled trial

Background

The mechanisms by which smoking cessation reduces cardiovascular disease risk are unclear. We evaluated longitudinal changes in carotid intima-media thickness among current smokers enrolled in a prospective, randomized smoking cessation clinical trial.

Methodology/Principal Findings

Subjects were enrolled in a randomized, double-blind, placebo-controlled trial of 5 smoking cessation pharmacotherapies and underwent carotid ultrasonography with carotid intima-media thickness measurement. Subjects were classified as continuously abstinent (biochemically confirmed abstinence at 6 months, 1 year, and 3 years post-quit attempt), intermittently abstinent (reported smoking at one of the three time points), or smoked continuously (reported smoking at all three time points). The primary endpoint was the absolute change (mm) in carotid intima-media thickness (ΔCIMT_max) before randomization and 3 years after the target quit date. Pearson correlations were calculated and multivariable regression models (controlling for baseline CIMT_max and research site) were analyzed. Among 795 subjects (45.2±10.6 years old, 58.5% female), 189 (23.8%) were continuously abstinent, 373 (46.9%) smoked continuously, and 233 (29.3%) were abstinent intermittently. There was a greater increase in carotid intima-media thickness among subjects who were continuously abstinent than among those who smoked continuously (p = 0.020), but not intermittently (p = 0.310). Antihypertensive medication use (p = 0.001) and research site (p<0.001) independently predicted ΔCIMTmax – not smoking status. The greatest increase in carotid intima-media thickness among continuous abstainers was related to increases in body-mass index (p = 0.043).

Conclusions/Significance

Smoking status did not independently predict ΔCIMT_max; increasing body-mass index and antihypertensive medication use were the most important independent predictors. The rapid reduction in cardiovascular disease events observed with smoking cessation is unlikely to be mediated by changes in subclinical atherosclerosis burden.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00332644","term_id":"NCT00332644"}}NCT00332644     

EffiCiency and Safety of an eLectronic cigAreTte (ECLAT) as Tobacco Cigarettes Substitute: A Prospective 12-Month Randomized Control Design Study

Background

Electronic cigarettes (e-cigarettes) are becoming increasingly popular with smokers worldwide. Users report buying them to help quit smoking, to reduce cigarette consumption, to relieve tobacco withdrawal symptoms, and to continue having a ‘smoking’ experience, but with reduced health risks. Research on e-cigarettes is urgently needed in order to ensure that the decisions of regulators, healthcare providers and consumers are based on science. Methods ECLAT is a prospective 12-month randomized, controlled trial that evaluates smoking reduction/abstinence in 300 smokers not intending to quit experimenting two different nicotine strengths of a popular e-cigarette model (‘Categoria’; Arbi Group Srl, Italy) compared to its non-nicotine choice. GroupA (n = 100) received 7.2 mg nicotine cartridges for 12 weeks; GroupB (n = 100), a 6-week 7.2 mg nicotine cartridges followed by a further 6-week 5.4 mg nicotine cartridges; GroupC (n = 100) received no-nicotine cartridges for 12 weeks. The study consisted of nine visits during which cig/day use and exhaled carbon monoxide (eCO) levels were measured. Smoking reduction and abstinence rates were calculated. Adverse events and product preferences were also reviewed.

Results

Declines in cig/day use and eCO levels were observed at each study visits in all three study groups (p<0.001 vs baseline), with no consistent differences among study groups. Smoking reduction was documented in 22.3% and 10.3% at week-12 and week-52 respectively. Complete abstinence from tobacco smoking was documented in 10.7% and 8.7% at week-12 and week-52 respectively. A substantial decrease in adverse events from baseline was observed and withdrawal symptoms were infrequently reported during the study. Participants’ perception and acceptance of the product under investigation was satisfactory.

Conclusion

In smokers not intending to quit, the use of e-cigarettes, with or without nicotine, decreased cigarette consumption and elicited enduring tobacco abstinence without causing significant side effects.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01164072","term_id":"NCT01164072"}}NCT01164072 {"type":"clinical-trial","attrs":{"text":"NCT01164072","term_id":"NCT01164072"}}NCT01164072     

Knowledge,Practices, and Attitudes of Emergency Contraception among Female University Students in KwaZulu-Natal,South Africa

Objective

The purpose of this study is to investigate the knowledge, practices, and attitudes among female university students in South Africa regarding emergency contraceptives (EC).

Methods

A cross-sectional study was conducted among 582 female university students who were selected using multi-stage sampling techniques. Multivariate logistic regression analysis was used to find significant predictors for EC awareness.

Results

The average age of the female students was 20.9 years (SD = 3.0) and 57.2% were presently sexually active. Overall, 49.8% of the participants reported having heard about EC prior to the study. Regarding sexual activities among the female students, 53.2% reported to have sex, and 21.2% of the sexually experienced students used EC prior to the study. Regarding the effectiveness of EC, 29.5% students said it could be used up to 72 hours after unprotected sexual intercourse, and 8% said it could be used just before sex. About two-thirds (61.8%) would recommend the use of EC and 63.2% would use it if they needed. The multivariate analysis indicated that students who were older (>20 years), presently sexually active, and living with their parents were more likely to be aware of EC (p<0.05).

Conclusion

The students’ knowledge and utilization of EC were low. Health education and promotion should be targeted towards these students, and the EC services should be offered on campus.     

Effect of Graphic Cigarette Warnings on Smoking Intentions in Young Adults

Introduction

Graphic warnings (GWs) on cigarette packs are widely used internationally and perhaps will be in the US but their impact is not well understood. This study tested support for competing hypotheses in different subgroups of young adults defined by their history of cigarette smoking and individual difference variables (e.g., psychological reactance). One hypothesis predicted adaptive responding (GWs would lower smoking-related intentions) and another predicted defensive responding (GWs would raise smoking-related intentions).

Methods

Participants were an online sample of 1,169 Americans ages 18–24, who were randomly assigned either to view nine GWs designed by the FDA or to a no-label control. Both the intention to smoke in the future and the intention to quit smoking (among smokers) were assessed before and after message exposure.

Results

GWs lowered intention to smoke in the future among those with a moderate lifetime smoking history (between 1 and 100 cigarettes), and they increased intention to quit smoking among those with a heavy lifetime smoking history (more than 100 cigarettes). Both effects were limited to individuals who had smoked in some but not all of the prior 30 days (i.e., occasional smokers). No evidence of defensive “boomerang effects” on intention was observed in any subgroup.

Conclusion

Graphic warnings can reduce interest in smoking among occasional smokers, a finding that supports the adaptive-change hypothesis. GWs that target occasional smokers might be more effective at reducing cigarette smoking in young adults.     

Implicit Motivational Impact of Pictorial Health Warning on Cigarette Packs

Objective

The use of pictorial warning labels on cigarette packages is one of the provisions included in the first ever global health treaty by the World Health Organization against the tobacco epidemic. There is substantial evidence demonstrating the effectiveness of graphic health warning labels on intention to quit, thoughts about health risks and engaging in cessation behaviors. However, studies that address the implicit emotional drives evoked by such warnings are still underexplored. Here, we provide experimental data for the use of pictorial health warnings as a reliable strategy for tobacco control.

Methods

Experiment 1 pre-tested nineteen prototypes of pictorial warnings to screen for their emotional impact. Participants (n = 338) were young adults balanced in gender, smoking status and education. Experiment 2 (n = 63) tested pictorial warnings (ten) that were stamped on packs. We employed an innovative set-up to investigate the impact of the warnings on the ordinary attitude of packs’ manipulation, and quantified judgments of warnings’ emotional strength and efficacy against smoking.

Findings

Experiment 1 revealed that women judged the warning prototypes as more aversive than men, and smokers judged them more aversive than non-smokers. Participants with lower education judged the prototypes more aversive than participants with higher education. Experiment 2 showed that stamped warnings antagonized the appeal of the brands by imposing a cost to manipulate the cigarette packs, especially for smokers. Additionally, participants’ judgments revealed that the more aversive a warning, the more it is perceived as effective against smoking.

Conclusions

Health warning labels are one of the key components of the integrated approach to control the global tobacco epidemic. The evidence presented in this study adds to the understanding of how implicit responses to pictorial warnings may contribute to behavioral change.     

Curcumins-Rich Curry Diet and Pulmonary Function in Asian Older Adults

Background

Research on the effects of dietary nutrients on respiratory health in human populations have not investigated curcumin, a potent anti-oxidant and anti-inflammatory compound present principally in turmeric used in large amounts in Asian curry meals.

Objectives

To examine the association of curry intake with pulmonary function among smokers and non-smokers.

Design

The frequency of curry intake, respiratory risk factors and spirometry were measured in a population-based study of 2,478 Chinese older adults aged 55 and above in the Singapore Longitudinal Ageing Studies.

Results

Curry intake (at least once monthly) was significantly associated with better FEV₁ (b = 0.045±0.018, p = 0.011) and FEV₁/FVC (b = 1.14±0.52, p = 0.029) in multivariate analyses that controlled simultaneously for gender, age, height, height-squared, smoking, occupational exposure and asthma/COPD history and other dietary or supplementary intakes. Increasing levels of curry intake (‘never or rarely’, ‘occasional’, ‘often’, ‘very often’) were associated with higher mean adjusted FEV₁ (p for linear trend = 0.001) and FEV₁/FVC% (p for linear trend = 0.048). Significant effect modifications were observed for FEV₁ (curry* smoking interaction, p = 0.028) and FEV₁/FVC% (curry*smoking interaction, p = 0.05). There were significantly larger differences in FEV₁ and FEV₁/FVC% between curry intake and non-curry intake especially among current and past smokers. The mean adjusted FEV₁ associated with curry intake was 9.2% higher among current smokers, 10.3% higher among past smokers, and 1.5% higher among non-smokers.

Conclusion

The possible role of curcumins in protecting the pulmonary function of smokers should be investigated in further clinical studies.     

Longitudinal Study of Spatially Heterogeneous Emphysema Progression in Current Smokers with Chronic Obstructive Pulmonary Disease

Background

Cigarette smoke is the main risk factor for emphysema, which is a key pathology in chronic obstructive pulmonary disease (COPD). Low attenuation areas (LAA) in computed tomography (CT) images reflect emphysema, and the cumulative size distribution of LAA clusters follows a power law characterized by the exponent D. This property of LAA clusters can be explained by model simulation, where mechanical force breaks alveolar walls causing local heterogeneous lung tissue destruction. However, a longitudinal CT study has not investigated whether continuous smoking causes the spatially heterogeneous progression of emphysema.

Methods

We measured annual changes in ratios of LAA (LAA%), D and numbers of LAA clusters (LAN) in CT images acquired at intervals of ≥3 years from 22 current and 31 former smokers with COPD to assess emphysema progression. We constructed model simulations using CT images to morphologically interpret changes in current smokers.

Results

D was decreased in current and former smokers, whereas LAA% and LAN were increased only in current smokers. The annual changes in LAA%, D, and LAN were greater in current, than in former smokers (1.03 vs. 0.37%, p = 0.008; −0.045 vs. −0.01, p = 0.004; 13.9 vs. 1.1, p = 0.007, respectively). When LAA% increased in model simulations, the coalescence of neighboring LAA clusters decreased D, but the combination of changes in D and LAN in current smokers could not be explained by the homogeneous emphysema progression model despite cluster coalescence. Conversely, a model in which LAAs heterogeneously increased and LAA clusters merged somewhat in relatively advanced emphysematous regions could reflect actual changes.

Conclusions

Susceptibility to parenchymal destruction induced by continuous smoking is not uniform over the lung, but might be higher in local regions of relatively advanced emphysema. These could result in the spatially heterogeneous progression of emphysema in current smokers.     

Association of CHRNA5-A3-B4 Variation with Esophageal Squamous Cell Carcinoma Risk and Smoking Behaviors in a Chinese Population

Background

CHRNA5-A3-B4, the gene cluster encoding nicotinic acetylcholine receptor subunits, is associated with lung cancer risk and smoking behaviors in people of European descent. Because cigarette smoking is also a major risk factor for esophageal squamous cell carcinoma (ESCC), we investigated the associations between variants in CHRNA5-A3-B4 and ESCC risk, as well as smoking behaviors, in a Chinese population.

Methods

A case-control study of 866 ESCC patients and 952 healthy controls was performed to study the association of polymorphisms (rs667282 and rs3743073) in CHRNA5-A3-B4 with cancer risk using logistic regression models. The relationships between CHRNA5-A3-B4 polymorphisms and smoking behaviors that can be quantified by cigarettes smoked per day (CPD) and pack-years of smoking were separately estimated with Kruskal-Wallis tests among all 840 smokers.

Results

CHRNA5-A3-B4 rs667282 TT/TG genotypes were associated with significantly increased risk of ESCC [adjusted odds ratio (OR) = 1.32, 95% confidence interval (CI) = 1.03 – 1.69, P = 0.029]. The increased ESCC risk was even higher among younger subjects (≤60 years) (OR = 1.44, 95% CI = 1.04 – 1.98, P = 0.024). These effects were not found in another polymorphism rs3743073. No evident association between the two polymorphisms and smoking behaviors was observed.

Conclusions

These results support the hypothesis that CHRNA5-A3-B4 is a susceptibility gene cluster for ESCC. The relationship between CHRNA5-A3-B4 and smoking behaviors in a Chinese population needs further investigation.     

Relationships among Smoking Habits,Airflow Limitations,and Metabolic Abnormalities in School Workers

Background

Chronic obstructive pulmonary disease is caused mainly by habitual smoking and is common among elderly individuals. It involves not only airflow limitation but also metabolic disorders, leading to increased cardiovascular morbidity and mortality.

Objective

We evaluated relationships among smoking habits, airflow limitation, and metabolic abnormalities.

Methods

Between 2001 and 2008, 15,324 school workers (9700 males, 5624 females; age: ≥30 years) underwent medical checkups, including blood tests and spirometry. They also responded to a questionnaire on smoking habits and medical history.

Results

Airflow limitation was more prevalent in current smokers than in ex-smokers and never-smokers in men and women. The frequency of hypertriglyceridemia was higher in current smokers in all age groups, and those of low high-density-lipoprotein cholesterolemia and diabetes mellitus were higher in current smokers in age groups ≥ 40 s in men, but not in women. There were significant differences in the frequencies of metabolic abnormalities between subjects with airflow limitations and those without in women, but not in men. Smoking index was an independent factor associated with increased frequencies of hypertriglyceridemia (OR 1.015; 95% CI: 1.012–1.018; p<0.0001) and low high-density-lipoprotein cholesterolemia (1.013; 1.010–1.016; p<0.0001) in men. Length of smoking cessation was an independent factor associated with a decreased frequency of hypertriglyceridemia (0.984; 0.975–0.994; p = 0.007).

Conclusions

Habitual smoking causes high incidences of airflow limitation and metabolic abnormalities. Women, but not men, with airflow limitation had higher frequencies of metabolic abnormalities.     

Cue-reactors: individual differences in cue-induced craving after food or smoking abstinence

Background

Pavlovian conditioning plays a critical role in both drug addiction and binge eating. Recent animal research suggests that certain individuals are highly sensitive to conditioned cues, whether they signal food or drugs. Are certain humans also more reactive to both food and drug cues?

Methods

We examined cue-induced craving for both cigarettes and food, in the same individuals (n = 15 adult smokers). Subjects viewed smoking-related or food-related images after abstaining from either smoking or eating.

Results

Certain individuals reported strong cue-induced craving after both smoking and food cues. That is, subjects who reported strong cue-induced craving for cigarettes also rated stronger cue-induced food craving.

Conclusions

In humans, like in nonhumans, there may be a “cue-reactive” phenotype, consisting of individuals who are highly sensitive to conditioned stimuli. This finding extends recent reports from nonhuman studies. Further understanding this subgroup of smokers may allow clinicians to individually tailor therapies for smoking cessation.     

Cigarette Experimentation and the Population Attributable Fraction for Associated Genetic and Non-Genetic Risk Factors

Background

We, and others, have shown that experimenting with cigarettes is a function of both non-genetic and genetic factors. In this analysis we ask: how much of the total risk of experimenting with cigarettes, among those who had not experimented with cigarettes when they enrolled in a prospective cohort, is attributable to genetic factors and to non-genetic factors?

Methods

Participants (N = 1,118 Mexican origin youth), recruited from a large population-based cohort study in Houston, Texas, provided prospective data on cigarette experimentation over three years. Non-genetic data were elicited twice – baseline and follow-up. Participants were genotyped for 672 functional and tagging variants in the dopamine, serotonin and opioid pathways.

Results

In the overall model, the adjusted combined non-genetic PAF was 71.2% and the adjusted combined genetic PAF was 58.5%. Among committed never smokers the adjusted combined non-genetic PAF was 67.0% and the adjusted combined genetic PAF was 53.5%. However, among cognitively susceptible youth, the adjusted combined non-genetic PAF was 52.0% and the adjusted combined genetic PAF was 68.4%.

Conclusions

Our results suggest there may be differences in genotypes between youth who think they will try cigarettes in the future compared to their peers who think they will not and underscore the possibility that the relative influence of genetic vs. non-genetic factors on the uptake of smoking may vary between these two groups of youth.

Impact

A clearer understanding of the relative role of genetic vs. non-genetic factors in the uptake of smoking may have implications for the design of prevention programs.     

Secondhand Smoke Exposure and Maternal Action to Protect Children from Secondhand Smoke: Pre- and Post-Smokefree Legislation in Hong Kong

Background

Smokefree legislation may protect children from secondhand smoke (SHS) in the home from smoking parent(s). We examined the effect of the 2007 smokefree legislation on children’s exposure to SHS in the home and maternal action to protect children from SHS exposure in Hong Kong.

Methods

Families with a smoking father and a non-smoking mother were recruited from public clinics before (2005–2006, n = 333) and after the legislation (2007–2008, n = 742) which led to a major extension of smokefree places in Hong Kong. Main outcomes included children’s SHS exposure in the home, nicotine level in mothers’ and children’s hair and home environment, mothers’ action to protect children from SHS, and their support to the fathers to quit.

Results

Fewer mothers post-legislation reported children’s SHS exposure in the home (87.2% versus 29.3%, p<0.01), which was consistent with their hair nicotine levels (0.36ng/mg versus 0.04ng/mg, p<0.01). More mothers post-legislation in the last month took their children away from cigarette smoke (6.3% versus 92.2%; p<0.01) and advised fathers to quit over 3 times (8.3% versus 33.8%; p<0.01). No significant change was found in the content of smoking cessation advice and the proportion of mothers who took specific action to support the fathers to quit.

Conclusions

SHS exposure in the home decreased and maternal action to protect children from SHS increased after the 2007 smokefree legislation. Maternal support to fathers to quit showed moderate improvement. Cessation services for smokers and specific interventions for smoking families should be expanded together with smokefree legislation.     

Association between Smoking Status and Obesity in a Nationwide Survey of Japanese Adults

Objective

A positive association between the number of cigarettes smoked per day and obesity has been reported, whereas how other smoking-related indices, such as pack-years and duration of smoking, are related with obesity has been less investigated. We analyzed the age-adjusted cross-sectional association between smoking and obesity in a general Japanese population.

Methods

We used data from a nationwide epidemiological study of Japanese adults (N = 23,106). We compared the prevalence of obesity (defined as body mass index ≥ 25kg/m²) among groups classified by smoking behavior, pack-years, number of cigarettes per day, duration of smoking, and duration and time of smoking cessation.

Results

In men, current smokers had a lower odds ratio (OR) for obesity of 0.80 (95% confidence interval (CI): 0.72–0.88) compared to non-smokers, whereas past smokers had a higher OR of 1.23 (95% CI: 1.09–1.37) compared to current smokers. In women, there were no differences in obesity between the three groups classified by smoking behavior. However, in both sexes, the prevalence of obesity tended to increase with pack-years and the number of cigarettes per day, but not with duration of smoking in current and past smokers. Further, in male smokers, the risks for obesity were markedly higher in short-term heavy smokers compared with long-term light smokers, even with the same number of pack-years. Regarding the impact of smoking cessation, female past smokers who quit smoking at an age > 55-years had an elevated OR of 1.60 (95% CI:1.05–2.38) for obesity.

Conclusions

In a general Japanese population, obesity is progressively associated with pack-years and number of cigarettes per day, but not with the duration of smoking. When investigating the association between obesity and cigarette smoking, the daily smoking burden and the duration of smoking require to be independently considered.