Smoking behaviour and compensation: A review of the literature with meta-analysis

The extent of compensation when switching to lower yield cigarettes is important for assessing risk of reduced yield products. Both completeness of and reasons for compensation are judged differently in the scientific and health community. We quantified compensation in a meta-analysis of suitable cross-sectional and brand-switching studies. For each dataset, we derived a compensation index (CI), 1 indicating complete and 0 no compensation. Meta-analyses provided overall estimates. We also reviewed evidence on compensation for nicotine and other factors. The unweighted mean CI (95% confidence interval) was 0.628 (0.513 to 0.742) from 38 estimates from 26 cross-sectional studies, and 0.723 (0.651 to 0.796) from 23 estimates from 19 brand-switching studies. Inverse-variance weighted estimates were 0.781 (0.720 to 0.842) and 0.744 (0.682 to 0.806). Brand-switching data indicate smokers compensate more completely over a narrower yield range. Smokers predominantly compensate by changing puffing volume, and little by changing cigarette consumption. The findings support compensation for nicotine, but other factors may also be relevant. Further investigation is needed using larger studies and different approaches to elucidate their role. We conclude that smokers switching to lower-yield cigarettes only partially compensate. Pharmacological nicotine effects are important, but other factors, including cigarette draw resistance, sensory effects of nicotine and conditioned stimuli may also contribute.     

Acute effect of glucose tablets on desire to smoke

Rationale: Previous research suggests that glucose may reduce desire to smoke during periods of abstinence but a definitive test is needed. Objective: The present study aimed to determine whether a single administration of oral glucose would reduce desire to smoke in abstaining smokers. Methods: Thirty-eight smokers attended the laboratory in the afternoon having not smoked since the previous evening. They rated their desire to smoke immediately before and at 5-min intervals for 20 min after chewing four 3-g glucose tablets (experimental group) or four matched placebo tablets (control group). Results: Ratings of desire to smoke decreased to a greater extent in the experimental than the control group. The effect was apparent after 10 min. There was no difference between the groups in terms of feeling ”sick” or ”satisfied”. Conclusion: A single dose of glucose has a relatively rapid and detectable effect on desire to smoke and the effect is not mediated by feeling sick. Glucose tablets may be useful in helping to control desire to smoke during periods of abstinence. Received: 25 March 1999 / Final version: 9 July 1999     

Impulsivity and cigarette smoking: delay discounting in current, never, and ex-smokers

Rationale: Impulsivity is implicated in drug dependence. Recent studies show problems with alcohol and opioid dependence are associated with rapid discounting of the value of delayed outcomes. Furthermore, discounting may be particularly steep for the drug of dependence. Objectives: We determined if these findings could be extended to the behavior of cigarette smokers. In particular, we compared the discounting of hypothetical monetary outcomes by current, never, and ex-smokers of cigarettes. We also examined discounting of delayed hypothetical cigarettes by current smokers. Methods: Current cigarette smokers (n=23), never-smokers (n=22) and ex-smokers (n=21) indicated preference for immediate versus delayed money in a titration procedure that determined indifference points at various delays. The titration procedure was repeated with cigarettes for smokers. The degree to which the delayed outcomes were discounted was estimated with two non-linear decay models: an exponential model and a hyperbolic model. Results: Current smokers discounted the value of delayed money more than did the comparison groups. Never- and ex-smokers did not differ in their discounting of money. For current smokers, delayed cigarettes lost subjective value more rapidly than delayed money. The hyperbolic equation provided better fits to the data than did the exponential equation for 74 out of 89 comparisons. Conclusions: Cigarette smoking, like other forms of drug dependence, is characterized by rapid loss of subjective value for delayed outcomes, particularly for the drug of dependence. Never- and ex-smokers could discount similarly because cigarette smoking is associated with a reversible increase in discounting or due to selection bias. Received: 3 March 1999 / Final version: 11 May 1999     

Neuroendocrine responses to nicotine and stress: enhancement of peripheral stress responses by the administration of nicotine

Habitual smokers frequently report that when they are stressed smoking helps them to relax. One potential explanation for the reported stress ameliorating effect of smoking is that cigarette consumption (nicotine self-administration) may decrease the sympathetic autonomic nervous system activity which is associated with the stress response. In the present study, rabbits prepared with chronic vascular cannulae were used to study the effects of nicotine administation on plasma corticosterone, catecholamine (epinephrine, norepinephrine and dopamine) and glucose responses to physical restraint stress. Nicotine (0.025, 0.05 or 0.10 mg nicotine base/kg body weight) was administered for 10 days prior to the stress test to allow for the development of habituation/tolerance to its acute toxic effects. Independent administration of nicotine, or the application of the physical restraint stressor, resulted in increases in the plasma concentrations of corticosterone, epinephrine, norepinephrine, and glucose. Nicotine administration during restraint stress enhanced the increase in plasma corticosterone and epinephrine, as compared to the responses induced by either factor alone. The results suggest that the stress ameliorating effect of continued cigarette smoking, as reported by habitual smokers, is not due to a reduction in the activity of the peripheral sympathetic autonomic nervous system.     

Smoking and human information processing

There is much evidence which indicates that smoking improves various aspects of human information processing (Wesnes 1987). The aim of the present study was to elucidate the stages of human information processing which are improved after cigarette smoking. Twelve regular smokers were tested on three cognitive tasks using a repeated measures design. Tasks used were: rapid visual information processing (RVIP), digit symbol substitution (DSST), and inspection time (IT). Performance parameters derived from these were intended to index different stages of the information processing sequence. Only those measures which involved a motor component were improved after smoking: response time on the RVIP task (P<0.025) and DSST performance (P<0.1). These findings suggest that central cholinergic pathways are involved in the late, response-related stages of the processing sequence.     

Nasal nicotine spray: a rapid nicotine delivery system

Plasma nicotine concentrations following administration by two types of nasal nicotine spray were compared in ten subjects. Absorption was particularly rapid during the first 2.5 min, the average rise in blood nicotine concentrations during this time being 8.6 ng/ml for the two products, followed by a small further rise to an average peak increase of 10.5 ng/ml 5 min after the dose of 2 mg nicotine base (mean 27.8 micrograms/kg). Despite a four-fold Cmax variation between subjects, the levels of individual subjects were fairly consistent across the two products. There were no significant differences between the two products in blood nicotine concentrations or cardiovascular responses, and the correlation between the AUCs from the two products was 0.68 (P = 0.01). Eight subjects reported subjective feelings of light-headedness or slight dizziness, which are not typical after slower absorption from nicotine gum or skin patches. Blood nicotine levels within the smoking range were soon built up with repeated doses, even in the subject with the least efficient nasal absorption. In a second study of ad libitum use under clinical conditions both products appeared sufficiently acceptable for therapeutic use as an aid to smoking cessation. There was no tendency to escalate to excessive use over 4 weeks, and blood nicotine concentrations in nine subjects averaged only 44% of their prior smoking levels. Only one subject had levels equivalent to prior smoking and possible reasons why this was not more common are discussed.     

Sex differences in the subjective and reinforcing effects of cigarette nicotine dose

RATIONALE: Some research with novel nicotine delivery methods suggests that nicotine itself may be less reinforcing in women than in men. However, sex differences in the reinforcing effects of nicotine dose via cigarette smoking have received little attention. OBJECTIVES: Sex differences in the subjective and reinforcing effects of smoking were examined as a function of two cigarette nicotine "dose" levels (moderate - subjects' preferred brand, > or = 0.7 mg yield; low - Carlton "ultra-light", 0.1 mg yield). METHODS: Male and female smokers ( n = 30) participated in three sessions, the first two involving independent assessment (only one brand available), and the third involving concurrent assessment (both brands available), of subjective ratings (e.g. "liking") and reinforcement for the two cigarette brands. Subjects were blind to the brand of each cigarette, and subjects abstained overnight prior to each session. Reinforcement was determined by responses on a computer task to earn single puffs on the designated cigarette. RESULTS: Subjective ratings differed between the low versus moderate cigarette nicotine dose under both independent and concurrent assessment conditions, as expected. Notably, this dose difference was smaller in women than in men (i.e. significant sex by dose interactions). The dose effect on smoke reinforcement also was smaller in women than men, but only under the independent and not concurrent assessment condition. CONCLUSIONS: These results indicate that cigarette nicotine dose is a less important influence on the subjective and, under some conditions, reinforcing effects of smoking in women than in men.     

Smoking cessation during pregnancy: A systematic literature review

Issues. Second‐hand smoke presents a health risk for a large group of entirely helpless nonsmokers: unborn children. Reliable data on women continuing to smoke during pregnancy are essential for effective preventive and interventional programs. The aim of this review is therefore to identify this risk group compared with spontaneous quitters of smoking. Approach. This systematic literature review is based solely on empirical original papers derived from samples of pregnant women smoking at the beginning of pregnancy. In accordance with the QUOROM Statement all population or clinic‐based samples were included. Collectives from intervention studies were not included. All studies were from developed nations and published between January 1997 and March 2008. Key Findings. A total of 19 studies were identified. The rate of quitters was between 4.0% and 69.7% for population‐based studies, and 26.5% and 47.0% for clinic‐based studies. A smoking partner, a large number of children, a high rate of tobacco consumption, as well as deficiencies in prenatal care were predictors of smoking during pregnancy. Implications. This study identifies risk factors and correlates and indicates common obstacles for women to quit smoking during pregnancy. Conclusion. The risk groups that can be defined based on our results are a key target population for preventive measures.[Schneider S, Huy C, Schütz J, Diehl K. Smoking cessation during pregnancy: A systematic literature review. Drug Alcohol Rev 2009]     

Effects of mecamylamine on human cigarette smoking and subjective ratings

Multiple measures of cigarette smoking, subjective effect and physiological effect were collected during 90-min test sessions in normal volunteers. Before sessions subjects received oral doses of mecamylamine (2.5, 5.0, 10, 20 mg) or placebo. Each dose and placebo was given three times in a randomized block sequence. Mecamylamine increased several measures of cigarette smoking, including number of cigarettes, number of puffs per cigarette, and expired air carbon monoxide level. Mecamylamine also produced modest, dose-related decreases in standing blood pressure and increases in standing heart rate. The subjective effects produced by mecamylamine were not characteristic of those of psychoactive drugs. Mecamylamine appears to have increased cigarette smoking by decreasing the effective dose level of nicotine available from cigarette smoking.     

Mecamylamine blocks the development of tolerance to nicotine in rats: implications for the mechanisms of tolerance

 Chronic injections of nicotine in rats produce upregulation of nicotinic cholinergic receptors. It has been proposed that this upregulation is a reflection of receptor desensitization and is the basis of functional tolerance. Mecamylamine, a non-competitive antagonist that blocks activation of nicotinic receptors, does not prevent upregulation produced by nicotine injections. This suggests that receptor activation is not a prerequisite for nicotine-induced receptor upregulation. Therefore, the present experiments tested whether mecamylamine would also fail to prevent the development of tolerance to nicotine. Six daily pairings of mecamylamine (1 mg/kg SC) with nicotine did block the development of tolerance to nicotine-induced antinociception (0.35 mg/kg) and to the ability of nicotine to suppress milk intake (0.66 mg/kg). In another experiment, six daily injections of mecamylamine, when given alone, did not alter the effects of a subsequent, acute injection of nicotine (0.35 mg/kg) in inducing antinociception in rats. There was no evidence that after six pairings of mecamylamine with nicotine, the cues associated with mecamylamine delivery took on conditioned antagonistic properties. These findings suggest that, unlike the receptor upregulation that results from either continuous or repeated nicotine administration, the tolerance following a short series of intermittent nicotine injections is dependent on receptor activation. Received: 20 May 1998 / Final version: 23 July 1998     

Nicotine self-administration in animals and humans: similarities and differences

 Studies of nicotine self-administration in animal and human subjects are discussed with respect to the behavioral paradigms employed, the effects of nicotine dose manipulations and nicotinic agonist/antagonist pre-treatment, and the role of neurochemical processes mediating reinforcement. Animal models have focused on intravenous nicotine self-administration, while most studies in human subjects have studied cigarette smoking behavior. Despite procedural differences, data from both animal and human studies show an inverted-U function relating nicotine dose to self-administration behavior, with maximal rates of responding occurring at intermediate doses of nicotine. Moreover, nicotine supplementation via non-contingent nicotine administration suppresses nicotine self-administration behavior in both animal models and human cigarette smokers. Nicotine antagonist treatment also reduces responding, although human studies usually find a transient increase in smoking, which is interpreted as an attempt to compensate for nicotinic receptor blockade. Amongst the neurochemical systems which have been examined, most emphasis has been given to dopamine. The mesolimbic dopamine pathway has been implicated in nicotine reward based on animal studies, and research with humans suggests a role for dopaminergic processes as well. However, dopaminergic blockade appears to increase cigarette smoking behavior in humans, while in animals nicotine self-administration is attenuated. Future research should exploit the complementary aspects of animal models and human paradigms to provide a coherent understanding of nicotine reinforcement. Animal models allow for analysis of anatomical and physiological mechanisms underlying nicotine self-administration; human studies validate the relevance to tobacco dependence and smoking cessation treatment. Received: 29 February 1996 / Final version: 23 September 1996     

Cotinine: effects with and without nicotine

 The purpose of this study was to examine the effects of the metabolite of nicotine, cotinine, in comparison to the effects of the nicotine patch, and a combination thereof during cigarette abstinence. More specifically, this study examined the effects of cotinine on physiological measures, subjective measures assessing craving, withdrawal symptoms and mood, and performance measures. A between-subject, 2 × 2 factorial design was used, with the daily administration of a 15-mg nicotine patch (Nicotrol) versus placebo patch as one factor and 80 mg of oral cotinine fumarate versus placebo drug as the other factor. Baseline measures were obtained while the subjects smoked cigarettes on an ad lib basis for 1 week. Subjects (n = 106) were then randomly assigned to one of four treatment conditions and for the next 14 days were required to be abstinent from cigarettes and take the study drugs. Cotinine administration, with or without nicotine patch, produced serum cotinine concentrations 3–4 times higher than during ad lib smoking. Results showed a reduction of self-reported tobacco withdrawal symptoms using the nicotine patch alone. Cotinine alone had no effect on withdrawal symptoms. However, when nicotine patch was combined with cotinine, the beneficial effect of the nicotine patch on withdrawal symptoms was absent. Therefore, cotinine appears to antagonize the effects of nicotine in the alleviation of withdrawal symptoms at concentrations higher than that attained from normal smoking. This effect does not appear to be mediated by changes in nicotine disposition. Received: 27 March 1997/Final version: 14 July 1997     

First cigarette on waking and time of day as predictors of puffing behaviour in UK adult smokers

Background

There is known inter- and intra-individual variation in how cigarettes are smoked. The aim of this study was to explore the influence of diurnal factors, particularly the first cigarette of the day, on puffing behaviour in a sample of adult smokers.

Methods

We recruited 130 adults aged 18–60 years who were smoking one of seven cigarette brands popular in the UK. Puffing behaviour was measured using a portable smoking device (CReSSmicro) through which participants smoked their cigarettes over a 24 h study period. The primary outcome was total smoke volume per cigarette (obtained by summing the puff volumes for each cigarette). Secondary outcome measures were puffing frequency, average puff volume, average puff flow, average puff duration and inter-puff interval.

Results

Total smoke volume was found to be significantly associated with the time the cigarette was smoked (P < 0.001), with cigarettes smoked between 2 and 10 a.m. being smoked less intensively than other cigarettes. After adjusting for time of cigarette, the first cigarette on waking was smoked slightly less intensively than other cigarettes and significantly so if smoked within 5 min of waking (P = 0.004).

Conclusions

This study suggests that cigarettes smoked during the night and early morning, including the first cigarette of the day, are puffed less intensively. This is a potentially important finding that merits more research given the importance of the first cigarette of the day and diurnal smoking patterns for determining dependence, cessation and relapse.     

Assessing the senok,sory role of nicotine in cigarette smoking

Thirty-two subjects were tested in five double-blind sessions (16 subjects in the morning following overnight smoking abstention, and 16 in the afternoon following ad-lib smoking). In each session, subjects smoked one of five experimental (EX) cigarettes having the following FTC nicotine/‘tar’ yields in mg: 0.08/8.5, 0.17/9.1, 0.37/9.8, 0.48/9.8, and 0.74/10.4. In a sixth session, subjects smoked a 0.71/8.6 commercial ‘light’ (CL) cigarette that was their usual brand. Before and after smoking, subjects subjectively rated their desire to smoke a cigarette of their usual brand and had blood smaples drawn. Following smoking subjects rated the cigarette on a variety of sensory dimensions; they also rated smoking satisfaction. Analysis of variance indicated that nicotine played an important sensory role for a variety of dimensions related to cigarette taste and sensory impact but not perceived draw. Principal-components analyses indicated that sensory factors were at least as important as nicotine pharmacology (indirectly indexed by the preto post-smoking rise in blood nicotine concentration) when considering smoking’s overall effects on satisfaction, product acceptance, and reduction in desire to smoke. A preliminary version of these data was presented at the International Symposium on Nicotine. The Effects of Nicotine on Biological Systems II, Montreal, July 21–24, 1994. The authors thank Drs. Brad Ingebrethsen, Deborah Pritchard, and two anonymous reviewers for comments on earlier drafts.     

The importance of sweet taste and caloric content in the effects of nicotine on specific food consumption

There is an inverse relationship between nicotine and body weight that has been partially explained by changes in consumption of sweet-tasting high calorie foods. The present research was designed to determine the relative importance of sweet taste and caloric content in the effects of nicotine on specific food consumption and body weight. Alzet miniosmotic pumps were implanted SC to administer saline or two different concentrations of nicotine to 63 male Sprague-Dawley rats for 17 days. Three experiments were performed in which animals had access to two foods, a nonsweet low calorie food and a target food (sweet low calorie, sweet high calorie, or nonsweet high calorie). Body weight, food consumption, and water consumption were measured daily before, during, and after drug administration. In all three experiments, there was an inverse relationship between nicotine and body weight. Both sweet taste and caloric content were involved in the effects of nicotine on specific food consumption and body weight, but sweet taste was particularly important. In fact, the effects of nicotine on body weight were attenuated when sweet-tasting low calorie foods were available. These findings have implications for controlling body weight gains after cessation of cigarette smoking.     

Social behaviour in rats lesioned with ibotenic acid in the hippocampus: quantitative and qualitative analysis

  Rationale: Neonatal ibotenic acid lesion of the ventral hippocampus was proposed as a relevant animal model of schizophrenia reflecting positive as well as negative symptoms of this disease. Before and after reaching maturity, specific alterations in the animals’ social behaviour were found. Objective: In this study, social behaviour of ventral hippocampal lesioned rats was analysed. For comparison, rats lesioned either in the ventral hippocampus or the dorsal hippocampus at the age of 8 weeks were tested. Methods: Rats on day 7 of age were lesioned with ibotenic acid in the ventral hippocampus and social behaviour was tested at the age of 13 weeks. For comparison, adult 8-week-old rats were lesioned either in the ventral or the dorsal hippocampus. Their social behaviour was tested at the age of 18 weeks. Results: It was found that neonatal lesion resulted in significantly decreased time spent in social interaction and an enhanced level of aggressive behaviour. This shift is not due to anxiety because we could not find differences between control rats and lesioned rats in the elevated plus-maze. Lesion in the ventral and dorsal hippocampus, respectively, in 8-week-old rats did not affect social behaviour. Conclusions: The results of our study indicate that ibotenic acid-induced hippocampal damage per se is not related to the shift in social behaviour. We favour the hypothesis that these changes are due to lesion-induced impairments in neurodevelopmental processes at an early stage of ontogenesis. Received: 24 July 1998 / Final version: 7 December 1998     

Personality and Cigarette Smoking in Italy,Poland, and the United States

This study reports data on over 700 young adults, undergraduate and medical students attending the University of Vermont, the University of Rome, and the Warsaw Medical Academy. Each subject provided information about cigarette smoking history and completed several personality, Type A, and life events inventories. Subjects were classified as nonsmoker, ex-smoker, and smoker. Each measure was analyzed by ANOVA on this basis, with gender and country as additional main effects. Smokers were found to have higher state anxiety, a lower lie score, and were more Type A than ex-smokers and nonsmokers, but they tended to report fewer life events and of lower value     

Long-term effects of switching to cigarettes with lower tar and nicotine yields

On switching to cigarettes with lower tar and nicotine yields, most individuals smoke more intensively, but it is not clear if this effect persists over a long period. Smoking behaviour was monitored in 10 male and 18 female volunteers at five monthly visits, smoking commercially available cigarettes (tar yield>10 mg), then for six more visits at 6-week intervals after switching (mean reduction of 5.9 mg tar and 0.45 mg nicotine). Puffing behaviour was monitored with a flow sensing holder, and measurements were made before and after smoking of plasma cotinine, carboxyhaemglobin and alveolar carbon monoxide. After switching, cotinine levels only fell 40% of that predicted from the fall in nicotine yields, and there were no systematic trends for the rest of the study. Puff volumes rose (reflecting perhaps the reduced draw resistance of the lower yield cigarettes), and remained higher thereafter. The number of puffs per cigarette appeared to rise on switching, but then decreased again. In conclusion, most effects of switching to lower yield cigarettes appeared to persist for at least 36 weeks, suggesting that the strategy of reducing exposure to cigarette smoke by lowering tar and nicotine yields may be of limited value.     

Smoking motives of daily and non-daily smokers: A profile analysis

Background

Non-daily or intermittent smoking is becoming common, but little is known about smoking patterns of intermittent smokers (ITS). This study assesses differences in the profile of smoking motives of non-daily, ITS and daily smokers (DS).

Methods

Participants were 218 DS and 252 ITS (152 converted ITS [CITS], who previously smoked daily, and 80 native ITS [NITS] who did not), not currently quitting, recruited by advertisement. ITS were defined as smoking 4–27 days per month; DS as smoking daily, 5–30 cigarettes per day. Participants completed the Wisconsin Inventory of Smoking Dependence Motives (WISDM), yielding scores for 13 different motives. The within-profile standard deviation expressed profile scatter (differentiation among motives), and profile shape was assessed on scores standardized for within-profile mean and standard deviation.

Results

There was no difference between ITS and DS on profile scatter. ITS and DS differed in the shape of the standardized score profile, with DS scoring higher on Tolerance, Craving, Automaticity, Loss of Control and Behavioral Choice motives, and ITS scoring higher on Cue Exposure, Weight Control, and Positive Reinforcement motives. CITS did not differ from NITS in profile scatter or profile shape.

Conclusion

ITS differ from DS in the relative importance of motives, with ITS emphasizing motives associated with acute, situational smoking, and DS emphasizing dependence-related motives. Among ITS, history of daily smoking did not influence the profile of motives.