Effects of nicotine on hunger and eating in male and female smokers

Stimulus functions of nicotine

Behavioral pharmacology has made vital contributions to the concepts and methods used in tobacco and other drug use research, and is largely responsible for the now generally accepted notion that nicotine is the primary component in tobacco that engenders and maintains tobacco use. One of the most important contributions of behavioral pharmacology to the science of drug use is the notion that drugs can act as environmental stimuli that control behavior in many of the same ways as other stimuli (e.g., visual, gustatory, olfactory). The purpose of this chapter is to provide an overview of research that illustrates the respondent and operant stimulus functions of nicotine, using a contemporary taxonomy of stimulus functions as a general framework. Each function is formally defined and examples from research on the behavioral pharmacology of nicotine are presented. Some of the factors that modulate each function are also discussed. The role of nicotine's stimulus functions in operant and respondent theories of tobacco use is examined and some suggestions for future research are presented. The chapter illustrates how a taxonomy of stimulus functions can guide conceptions of tobacco use and direct research and theory accordingly.

Nicotine and energy balance: A review examining the effect of nicotine on hormonal appetite regulation and energy expenditure

Nicotine has been shown to decrease appetite, food intake (FI) and body weight, but the mechanisms are unclear. The purpose of this review was to examine research on the effects of nicotine on energy balance by exploring physiological mechanisms and hormone regulation related to FI, subjective appetite and energy expenditure (EE). We searched PubMed and MEDLINE, and included articles investigating the effects of nicotine on central appetite regulation, FI, leptin, peptide-YY (PYY), ghrelin, glucagon-like peptide-1 (GLP-1), adiponectin, cholecystokinin (CCK), orexin, and EE. A total of 65 studies were included in the qualitative synthesis and review. Our findings suggest that the decrease in appetite and FI may be attributed to nicotinic alterations of neuropeptide Y (NPY) and pro-opiomelanocortin (POMC) but the effect of nicotine on FI remains unclear. Furthermore, nicotine increases resting EE (REE) and physical activity EE (PAEE) in both smokers and non-smokers; and these increases may be a result of the catecholaminergic effect of nicotine. Decreases in body weight and appetite experienced by nicotine users results from increased EE and changes in the central hypothalamic regulation of appetite. There is not enough evidence to implicate a relationship between peripheral hormones and changes in appetite or FI after nicotine use. Although nicotine increases REE and PAEE, the effect of nicotine on other components of EE warrants further research. We conclude that further research evaluating the effect of nicotine on appetite hormones, FI and EE in humans is warranted.

Targeting Mediators of Smoking Persistence with Intranasal Insulin

Rapid-acting, non-irritating nasal treatment options for smoking cessation pharmacotherapy are lacking. The halt in development is due, in part, to difficulty in delivering compounds across the blood brain barrier. Recently, in both human and animal models, insulin was shown to be capable of being transported to the cerebrospinal fluid and various brain regions via the “nose-to-brain” pathway, which bypasses the blood brain barrier, but is not free of its own unique, though different from blood brain barrier, challenges. This review will first evaluate and critique pharmacokinetic and pharmacodynamic evidence of intranasal insulin (i.e., nose-to-brain) delivery. As intranasal insulin has been shown in clinical trials to be effective in reducing nicotine cravings, in the remainder of the review, hypothesis-generating literature for additional mediators (i.e., other than the already shown nicotine craving) of smoking persistence will be reviewed. In particular, weight gain, impulsive behavior, and anhedonia have been shown to contribute to the inability to quit smoking. For each of these, after reviewing how the mediator promotes smoking, intranasal insulin literature from animal and clinical models will be critiqued in assessing whether a hypothesis may be generated that intranasal insulin may alleviate it, thereby potentially contributing to a successful smoking cessation outcome.

Gender differences influence overweight smokers' experimentation with electronic nicotine delivery systems

INTRODUCTION

Overweight and obese tobacco users possess increased risk of cancer, diabetes, heart disease and chronic tobacco-related disease. Efforts to prevent tobacco-related health risk in this comorbid population would be informed by better understanding and monitoring of trends in the concurrent use of electronic nicotine delivery systems (ENDS) among smokers in the US marketplace.

METHOD

The California Longitudinal Smokers Study (CLSS) established a cohort of current cigarette smokers in 2011 who were surveyed for tobacco use and health behavior at baseline and again in 2012 at follow-up.

RESULTS

We observed a large increase in reported experimentation with ENDS. As hypothesized, overweight or obese smokers were more likely to report experimentation with ENDS, an increase that was also observed among women. Experimentation with ENDS was not associated with a reduction in use of cigarettes or a decrease in cigarette dependence in this high risk population of smokers.

CONCLUSIONS

Continued surveillance of this vulnerable population is needed to better understand how experimentation with new ENDS products may impact health, facilitate switching to non-combustible tobacco or facilitate persistent cigarette dependence.

Night Eating Syndrome in Major Depression and Anxiety Disorders

INTRODUCTION

The purpose of this study is to investigate the prevalence and the clinical features of night eating syndrome (NES) in patients with depression and anxiety disorders.

METHOD

The study was conducted at Bakırköy State Hospital for Mental Health and Neurological Disorders. Three-hundred out-patients who had major depression (MD), panic disorders (PD), general anxiety disorders (GAD) and obsessive-compulsive disorders (OCD) participated in the study. The semi-structured socio-demographic form, the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I), Night Eating Questionnaire, and NES Evaluation Questionnaire were implemented.

RESULTS

In our sample, the prevalence of the NES was 15.7% (n=47). NES frequency was significantly higher in the patients diagnosed with major depression (MD 22%, GAD 7.8%, OCD 12.5%, PD 14%). Smoking, presence of past suicide attempts, rates of antipsychotic drugs use, and average scores of body mass index (BMI) were significantly higher in the patients who had NES. In this sample, depression, BMI, and smoking were found to be determinants of NES.

CONCLUSION

This study shows that NES may be frequently observed in patients admitted to psychiatric clinics, especially in those with major depression. Evaluation of NES in psychiatric patients may help the treatment of the primary psychopathology and prevent the adverse effects, like weight gain, which may reduce the quality of life.

Altered hypothalamic response to food in smokers

BACKGROUND

Smoking cessation is often followed by weight gain. Eating behaviors and weight change have been linked to the brain response to food, but it is unknown whether smoking influences this response.

OBJECTIVE

We determined the influence of smoking status (smokers compared with nonsmokers) on the brain response to food in regions associated with weight changes in nonsmokers.

DESIGN

In study 1, we used functional MRI (fMRI) to identify regions of the brain associated with weight change in nonsmokers. BMI and the brain response to a milk shake, which is a palatable and energy-dense food, were measured in a group of 27 nonsmokers (5 men). Sixteen subjects (3 men) returned 1 y later for BMI reassessment. The change in BMI was regressed against the brain response to isolate regions associated with weight change. In study 2, to determine whether smokers showed altered responses in regions associated with weight change, we assessed the brain response to a milk shake in 11 smokers. The brain response to a milk shake compared with a tasteless control solution was assessed in 11 smokers (5 men) in comparison with a group of age-, sex- and body weight-matched nonsmokers selected from the pool of nonsmokers who participated in study 1.

RESULTS

The response in the midbrain, hypothalamus, thalamus, and ventral striatum was positively associated with weight change at the 1-y follow-up in 16 nonsmokers. Compared with nonsmokers, smokers had a greater response to milk shakes in the hypothalamus.

CONCLUSION

Smokers display an altered brain response to food in the hypothalamus, which is an area associated with long-term weight change in nonsmokers.

Nicotinic regulation of energy homeostasis

INTRODUCTION

The ability of nicotine, the primary psychoactive substance in tobacco smoke, to regulate appetite and body weight is one of the factors cited by smokers that prevents them from quitting and is the primary reason for smoking initiation in teenage girls. The regulation of feeding and metabolism by nicotine is complex, and recent studies have begun to identify nicotinic acetylcholine receptor (nAChR) subtypes and circuits or cell types involved in this regulation.

DISCUSSION

We will briefly describe the primary anatomical and functional features of the input, output, and central integration structures of the neuroendocrine systems that regulate energy homeostasis. Then, we will describe the nAChR subtypes expressed in these structures in mammals to identify the possible molecular targets for nicotine. Finally, we will review the effects of nicotine and its withdrawal on feeding and energy metabolism and attribute them to potential central and peripheral cellular targets.

Effects of cigarette smoke exposure and its cessation on body weight, food intake and circulating leptin, and ghrelin levels in the rat

INTRODUCTION

Smoking is associated with loss of body weight (BW) and reduced appetite, while smoking abstinence with the opposite effect. The role of peripheral signaling by appetite-controlling hormones leptin and ghrelin is not clear. In the present study, the relationship of circulating leptin and ghrelin with BW and food intake rate (FIR) changes was studied during cigarette smoke exposure (CSE) and after its cessation in the rat.

METHODS

Male Wistar rats were subjected to CSE for 8 weeks by confinement to plexiglass chambers (Group S). Control animals were confined to identical chambers without smoke (Group C). During CSE and an equivalent follow-up period, BW and FIR was recorded and serum leptin and ghrelin levels were measured.

RESULTS

A sharp decrease in BW was noted during the first 4 weeks of CSE, while FIR, after a substantial decrease noted at Week 1, returned to control levels. Thereafter, rats started to regain their BW until they reached control levels by the 1st week postCSE. BW regain was accompanied by a rebound increase of FIR, which plateaued during the first 4 weeks postCSE and then normalized. Serum leptin was decreased in Group S during both periods, normalizing at the 7th week postCSE. Ghrelin levels did not differ between groups.

CONCLUSIONS

Circulating leptin could not explain by its own BW and FIR changes during the first few week of CSE in rats, in contrast to the rest of the CSE period as well as after its cessation. Serum ghrelin levels did not justify BW and FIR changes.

The reinforcement-enhancing effects of nicotine: implications for the relationship between smoking, eating and weight

Concerns about body weight represent an important barrier to public health efforts aimed at reducing smoking. Epidemiological studies have found that current smokers weigh less than non-smokers, smoking cessation results in weight gain, and weight restriction is commonly cited as a reason for smoking. The mechanisms underlying the relationship between smoking and weight are complex and may involve a number of factors including changes in caloric intake, physical activity, metabolic rate, and lipogenesis. Amongst these possible mechanisms, nicotine-induced enhancement of food reinforcement may be particularly important. In this paper, we first review data from our laboratory that highlight two distinct ways in which nicotine impacts reinforced behavior: 1) by acting as a primary reinforcer; and 2) by directly (non-associatively) enhancing the reinforcing effects of other stimuli. We then elaborate on the reinforcement-enhancing effects of nicotine as they pertain to behaviors and stimuli related to food. Data from both laboratory animals and humans support the assertion that nicotine enhances the reinforcing efficacy of food and suggest that the influence of these effects on eating may be most important after nicotine cessation when nicotine's effects on satiety subside. Finally, we discuss the theoretical and clinical implications of this perspective for understanding and addressing the apparent tradeoff between smoking and weight gain. Better understanding of the mechanisms underlying the reinforcement-enhancing effects of nicotine broadly, and the effects on food reinforcement per se, may aid in the development of new treatments with better long term outcomes.

Effect of smoking status on total energy expenditure

Individuals who smoke generally have a lower body mass index (BMI) than nonsmokers. The relative roles of energy expenditure and energy intake in maintaining the lower BMI, however, remain controversial. We tested the hypothesis that current smokers have higher total energy expenditure than never smokers in 308 adults aged 40-69 years old of which 47 were current smokers. Energy expenditure was measured by doubly labeled water during a two week period in which the subjects lived at home and performed their normal activities. Smoking status was determined by questionnaire. There were no significant differences in mean BMI (mean ± SD) between smokers and never smokers for either males (27.8+5.1 kg/m2 vs. 27.5+4.0 kg/m2) or females (26.5+5.3 kg/m2 vs. 28.1+6.6 kg/m2), although the difference in females was of similar magnitude to previous reports. Similarly, total energy expenditure of male smokers (3069+764 kcal/d) was not significantly different from that of never smokers (2854+468 kcal/d), and that of female smokers (2266+387 kcal/d) was not different from that of never smokers (2330+415 kcal/d). These findings did not change after adjustment for age, fat-free mass and self-reported physical activity. Using doubly labeled water, we found no evidence of increased energy expenditure among smokers, however, it should be noted that BMI differences in this cohort also did not differ by smoking status.

Sex differences in nicotine action

Accumulating evidence suggests that the antecedents, consequences, and mechanisms of drug abuse and dependence are not identical in males and females and that gender may be an important variable in treatment and prevention. Although there has been a decline in smoking prevalence in developed countries, females are less successful in quitting. Tobacco use is accepted to be a form of addiction, which manifests sex differences. There is also evidence for sex differences in the central effects of nicotine in laboratory animals. Although social factors impact smoking substantially in humans, findings from nonhuman subjects in controlled experiments provide support that sex differences in nicotine/tobacco addiction have a biological basis. Differences in the pharmacokinetic properties of nicotine or the effect of gonadal hormones may underlie some but not all sex differences observed. Laboratory-based information is very important in developing treatment strategies. Literature findings suggest that including sex as a factor in nicotine/tobacco-related studies will improve our success rates in individually tailored smoking cessation programs.

Consequences of smoking for body weight, body fat distribution, and insulin resistance

Our aim was to critically evaluate the relations among smoking, body weight, body fat distribution, and insulin resistance as reported in the literature. In the short term, nicotine increases energy expenditure and could reduce appetite, which may explain why smokers tend to have lower body weight than do nonsmokers and why smoking cessation is frequently followed by weight gain. In contrast, heavy smokers tend to have greater body weight than do light smokers or nonsmokers, which likely reflects a clustering of risky behaviors (eg, low degree of physical activity, poor diet, and smoking) that is conducive to weight gain. Other factors, such as weight cycling, could also be involved. In addition, smoking increases insulin resistance and is associated with central fat accumulation. As a result, smoking increases the risk of metabolic syndrome and diabetes, and these factors increase risk of cardiovascular disease. In the context of the worldwide obesity epidemic and a high prevalence of smoking, the greater risk of (central) obesity and insulin resistance among smokers is a matter of major concern.

The appetite-suppressant effect of nicotine is enhanced by caffeine

AIM

To test whether the anorectic effect of nicotine may be amplified by caffeine.

METHODS

Chewing gums with nicotine and caffeine were administered to 12 healthy young men of normal weight. Different combinations of 0, 1 or 2 mg of nicotine and 0, 50 or 100 mg of caffeine were applied during a 2-h period in a randomized, double blind, cross over design. Appetite sensations were measured using visual analogue scales.

RESULTS

Hunger and prospective food consumption were negatively associated with the increasing doses of nicotine, whereas satiety and fullness were positively associated with the increasing doses of nicotine (p < 0.05). Caffeine appeared to amplify the effects of nicotine on hunger and fullness as a caffeine x nicotine x time interaction was observed in these scores (p < 0.05). The 2-mg dose of nicotine in combination with the 100-mg dose of caffeine caused nausea in four of the non-smokers. However, the effects of nicotine and the caffeine x nicotine x time interaction persisted after the exclusion of these subjects.

CONCLUSION

Caffeine added to nicotine chewing gum appears to amplify its attenuating effects on appetite and the combinations of 1-mg of nicotine with caffeine seem to be well tolerated.

Opioid craving and seeking behavior in physically dependent volunteers: effects of acute withdrawal and drug reinforcement opportunity

This study examined whether acute opioid withdrawal and drug reinforcement opportunity increase opioid craving and seeking behavior. The author used a 3 x 2 within-subject randomized crossover design to assess craving and operant behavioral effects of 3 pretreatments (naloxone 0.1 mg/70 kg, fentanyl 0.75 mg/70 kg, or saline iv) and drug or money reinforcement opportunity in 8 methadone-maintained volunteers. Each pretreatment was paired with response-contingent (15 x fixed-ratio 100) delivery of drug (fentanyl 1.5 mg/70 kg iv) and money (rated equivalent of fentanyl) in different sessions. Naloxone significantly increased opioid craving, withdrawal signs, and symptoms, but not operant behavior, relative to saline and fentanyl pretreatment. However, drug versus money reinforcement opportunity did not significantly increase opioid craving or seeking behavior.

Long-Term Effects of High Doses of Nicotine on Feeding Behavior and Brain Nitric Oxide Synthase Activity in Female Mice

We studied the long-term effects of repeated doses of nicotine, causing dependence, 120 days after its withdrawal on feeding behavior and on brain nitric oxide (NO) formation in female mice. Nicotine dependence was induced by subcutaneous (s.c.) nicotine injection (2 mg/kg, four injections daily) for 14 days. Daily food intake was evaluated for the entire observational period (120 days). Moreover, 30, 60, and 120 days after nicotine withdrawal, we evaluated food intake, nitrite/nitrate levels, and nitric oxide synthase (NOS) activity and expression in the hypothalamus after food deprivation (24 h). In animals in which nicotine dependence was induced (NM), daily food intake was similar to that of controls (M). However, following food deprivation, NM mice showed i) a significant increase in food intake, ii) changes in weight gain and in hypothalamic nitrite/nitrate levels, and iii) enhancement of hypothalamic neuronal NOS (nNOS) activity. Results indicate that high doses of nicotine producing dependence induce long-term changes in feeding behavior consequent to food deprivation associated to alterations in the brain nitrergic system.

Dietary restriction and nicotine can reduce anxiety in female rats

Anxiety may play a role in the initiation of smoking and there is evidence to suggest that sex and age may predetermine responses to nicotine. At present, the greatest increase in smoking is in women and it is often accompanied by dieting. The purpose of the present study was to investigate how the impact of dietary restriction might modify the effects of nicotine in female adult and adolescent rats. The effects of nicotine in the elevated plus-maze test of anxiety were compared in free-feeding animals and those subjected to dietary restriction that reduced body weight to 85% of free-feeding weight. In nondeprived adult females, nicotine (0.05-0.5 mg/kg, s.c.) reduced the percentage of time spent on the open arms, indicating anxiogenic effects. However, the effects of nicotine were dramatically changed in food-restricted adult females and 0.05 mg/kg had a striking anxiolytic effect. No significant effects of nicotine were found in the adolescent female rats, suggesting a role of circulating sex hormones in modulating nicotine's effects on anxiety. However, in the adolescent females, dietary restriction significantly increased the percentages of time spent and entries onto the open arms, without changing closed arm entries, indicating an anxiolytic effect. These results raise the important possibility that, in prepubertal girls, dietary restriction may have anxiolytic effects and this might contribute to the onset of anorexia. Circulating female hormones reduce this effect, but in adult females the combination of dietary restriction and nicotine may have important anxiolytic effects that impact on the initiation of regular smoking.

Nicotine alters the usual reciprocity between meal size and meal number in female rat

Tobacco smoking reduces appetite and body weight (BW). Cessation of smoking leads to hyperphagia and weight gain. Daily food intake (FI) is a function of meal number (MN) and meal size (MZ), i.e., FI=MNxMZ. Under normal conditions, the female Fischer rat has a periodic reciprocal fluctuation between MZ and MN corresponding to phase of estrous cycle. Wide fluctuations between MZ and MN compensate each other to keep FI constant. Nicotine (5 mg/kg BW/day) was infused via osmotic minipump for 7 days. Controls received saline. FI, MZ, and MN were measured by an Automated Computerized Rat Eater Meter. Nicotine significantly decreased BW and FI via a decrease in MZ without compensatory increase of MN. Nicotine cessation led to hyperphagia, normalizing BW loss via an increase in MZ, which exceeded a compensatory decrease in MN. Nicotine significantly prolonged the estrous cycle by an extension of proestrous phase. Nicotine significantly lengthened the intermeal interval (IMI), delaying the start of the next meal and simultaneously decreasing subsequent MZ. Stopping nicotine led to normalization of IMI and MZ. Data show that nicotine alters the usual reciprocal regulation between MZ and MN and leads to a prolongation of the estrous cycle.

Maternal smoking and reduced duration of breastfeeding: a review of possible mechanisms

AIM

To systematically review the possible mechanisms by which maternal smoking affects lactation.

METHODS

Databases (Medline, CINAHL, Current Contents, Psychinfo, Sociological Abstracts and the Cochrane Library) were searched for smoking and breastfeeding or infant feeding. The Journal of Human Lactation and Birth were hand-searched, searches were also conducted at NMAA's Lactation Resource Centre and references cited were located where appropriate. Articles were divided into the various ways that smoking could affect breastfeeding and were tabulated.

RESULTS

Most studies were conducted on small samples of animals or humans; the majority were prior to 1985. Most animal studies exposed the animals to much greater levels of nicotine than those to which humans are exposed. Most studies did not examine if breastfeeding behaviour was similar in smokers and non-smokers, and did not consider that any physiological difference found could be the result of poor lactation practices, rather than the cause of poor lactation in smokers. The definition of breastfeeding infants was also problematic in many studies. The effect of smoking on oxytocin in women was only examined in one study, and no effect was found, yet a negative effect of smoking on oxytocin release is reported in the breastfeeding literature.

CONCLUSION

Although there is consistent evidence that women who smoke breastfeed their infants for a shorter duration than non-smokers, the evidence for a physiological mechanism is not strong.

Effects of three doses of transdermal nicotine on post-cessation eating, hunger and weight

Smokers were randomly assigned to 0, 7, 14 or 21 mg doses of transdermal nicotine and had their eating and weight followed for 6 weeks. Among the 66 subjects who were abstinent for all 6 weeks, caloric, carbohydrate and fat intake, hunger, and weight increased in those on placebo, but alcohol, caffeine and protein intake did not. Nicotine patch decreased caloric, carbohydrate and fat intake in a dose-related manner, showed a trend for weight and showed no effect for hunger. Neither abstinence from smoking nor nicotine therapy shifted the percent of calories from sweets or carbohydrates. We conclude nicotine replacement reduces post-cessation increases in eating but does not have a specific effect on sweet intake.

Anthropometric status and resting metabolic rate in users of the areca nut and smokers of tobacco in rural Sarawak

The areca nut is chewed by many of the world's population, mainly in South and Southeast Asia. Anthropometric data for 458 Sarawaki adults aged over 24 years, measured both in 1990 and in 1996, were examined in relation to use of tobacco and areca nut. Compared to non-smokers, smoking men were significantly taller and slightly (not significantly) thinner in both years, while smoking women were thinner in 1990 and slightly (not significantly) thinner in 1996. In both sexes there was an increase in the mean and range of body mass index (BMI, W/H2) over the 6-year interval. Smoking women showed a significantly smaller increment in BMI after allowing for areca nut use, which was associated with a similar trend, and this finding depended on including areca use in the model. The trend for men was similar. Possible effects of areca use could reflect variation in 'affluence' or conservatism, or appetite suppression. However, resting metabolic rate in 54 men and 70 women aged 24-60 years was associated with areca use. This association appeared to be mediated by the maximum room temperature of the 24 h preceding measurement. In women, a significant curvilinear association of RMR with maximum temperature was found in users of areca nut but not in non-users. In men, RMR was 7% higher (p < 0.05) in users of areca nut than in non-users, after allowing for age, height, weight, the sum of four skinfold thicknesses, and haemoglobin, but the association with maximum temperature was similar in both groups. It is speculated that constituents of areca nut modulate thermoregulatory pathways, resulting in prolonged temperature-dependent and hyperthermic heat production in this population; that males are more responsive to this effect than females; and that by this mechanism, and possibly also through centrally mediated effects on appetite for food, areca use could contribute to long-term variation in energy balance represented by change in BMI.

Retracing the steps of Marco Polo: from clinical trials to diffusion of interventions for smokers

We report the results from a series of four controlled trials which evaluate efficacy, effectiveness, and implementation of interventions for smokers, and then discuss diffusion of our program in feasibility studies both nationally in Australia and internationally. In our first study we reported that when general practitioners delivered moderately brief advice to smokers, they have a 36% abstinence rate at three years. In the second study we found that doctors achieve a 12% abstinence at one year after giving minimal advice to patients, and when using a more involved intervention, quit rates of just less than 20% at one year. In the third and fourth studies of utilization of the smoking cessation program we report that reinforcement contact following a 2-hour training workshop increased doctors' use of a smoking cessation program at 6 months compared to no contact. The challenge of translating research findings into practice for the benefit of doctors in Australia as well as in a low-income country such as China, is described in two feasibility studies. Over the past 11 years we have disseminated the program nationally in Australia, and over 4500 doctors have been trained. Diffusion theory provides a useful model which has guided us in our implementation efforts in Australia and is being used to allow us to introduce the smoking cessation intervention for Chinese doctors to use.

Substance use: toward an understanding of its relation to nutrition-related attitudes and behavior among Israeli high school youth

PURPOSE

To study the distribution, prevalence, determinants, and association between substance use (e.g., cigarettes, alcohol, and illegal drugs) and eating attitudes and behavior of high school students in the Negev region of Israel in order to provide an improved basis for prevention and health services.

METHODS

An anonymous questionnaire regarding attitudes and behavior related to substance use and eating (e.g., breakfast before school, a snack or meal during school time, and three meals a day) was answered by 1,513 high school age youth.

RESULTS

The study participants were at greater risk of poor eating behavior if they: (1) used cigarettes, alcohol, and/or illicit substances (p < .01); and (2) were female (p < .01). It was found that girls who used cigarettes were more likely than other young people studied not to eat properly and not to know about the relation between proper eating behavior and personal health (p < .05). Regardless whether cigarettes, alcohol, or illicit substances were used or not used, more than 50% of the youth reported not eating breakfast and 30% indicated they did not eat three meals daily.

CONCLUSIONS

There are many concerns about the use and abuse of both licit and illicit substances among adolescents. More attention, however, needs to be given to the relationship between substance use and the attitudes and behavior of young people toward their health, including proper eating habits. The results support the need to develop drug prevention and health programs that are more comprehensive in terms of addressing the broad range of factors associated with adolescent growth and development.

Gender, dietary restraint, and smoking's influence on hunger and the reinforcing value of food

Smoking may enhance satiety following meal consumption, thereby reducing subsequent eating (i.e., between-meal snacks), especially in women high in dietary restraint. Female smokers (n = 20, 10 high and 10 low restraint) and male smokers (n = 10) participated in two sessions, involving overnight abstinence from food and smoking (smoking abstinence day) or from food only (smoking day), in a within-subjects design. The reinforcing value of food was determined by the number of responses made to obtain food reinforcers (100-kcal snack portions) vs. money using a concurrent schedules computer task. Subjects were given a small caloric load on each day followed by access to food vs. money. On the smoking day, subjects were allowed to smoke every 30 min during the session as well as ad lib before the session. Self-reported hunger was also assessed upon arrival (after fasting) and following the caloric load during each session. Results indicated no effect of smoking on initial hunger rating, after fasting, but hunger ratings following the caloric load declined significantly more during smoking vs. abstinence days for all subjects, consistent with an enhancement of postmeal satiety due to smoking. There was no overall main effect of smoking on food-reinforced responding. However, responding for food was significantly less during the smoking vs. abstinence days for high-restraint females only and not for low-restraint females or for males. These findings indicate that smoking's acute influence on reducing food intake does not reflect a broad gender difference but may be specific to dietary restraint.

Individual variability in responses to nicotine

Individual variability in acute responses to nicotine, which may be defined as variable magnitude of effects following controlled dosing, is generally attributed to stable characteristics of tobacco users such as genetic/constitutional factors or to chronic behavioral factors (e.g., long-term use of other drugs). Often overlooked, however, is that such variability may also be due to the transient influence of the situational factors in which people consume nicotine, such as acute stress or physical activity. Results of selected studies from the author's laboratory provide examples of each of these sources of variability in nicotine responding on subjective, behavioral, and physiological measures. All studies used a nasal spray method of nicotine dosing or controlled smoking (paced puffing) to control acute nicotine exposure, an essential methodological feature of any research on individual differences in acute responses to nicotine. As an example of genetic/constitutional factors, gender differences in nicotine responding have begun to receive some attention, with few differences emerging. However, females may be more responsive than males to nonnicotine stimuli associated with smoking (e.g., sight and taste of smoke). In terms of chronic behavioral factors, long-term use of nicotine produces attenuation of most subjective and some behavioral effects of nicotine, reflecting chronic tolerance, and the possibility that chronic use of other drugs may alter responses to nicotine (i.e., cross-tolerance or cross-sensitization) deserves greater study. Of particular emphasis in this review is the modulating influence of acute situational factors on nicotine responding. Human studies have shown that magnitude of nicotine's subjective effects may depend on the predrug subjective state, level of physical activity vs. rest, and concurrent acute intake of other drugs, among other situational factors. Proper consideration of these situational factors may reveal the greatest source of individual variability in responding to nicotine and clarify the impact of more stable genetic/constitutional or chronic environmental factors.

The relationship of gender, diet patterns, and body type to weight change following smoking reduction: a multivariate approach

We compared two regression models of posttobacco-reduction weight gain using nutrient intake and other variables as predictors. The first model involved the regression of weight gain, in pounds, against absolute change in the nutrient predictor variables. The second model utilized a data transformation, regressing percent change from initial body weight against change in nutrient:weight ratios. Both models included age, initial body-mass index (BMI), and change in nicotine exposure as additional predictors. Separate analyses were conducted for each gender and for obese and normal-weight participants. The results indicated that adjusting changes in nutrient intake for weight predicted posttreatment weight gain better than absolute changes in nutrient intake. The most accurate prediction was observed for normal-weight individuals, with both genders simultaneously in the model. Increase in weight was predicted by a decrease in nicotine exposure, a decrease in calories per pound, decrease in carbohydrates per pound, and an increase in a carbohydrate:protein ratio. Neither model predicted weight change for obese participants. These findings suggest that adjusting nutrient intake for body weight obviates the need for separate examination of each gender, and that a reduction in nicotine exposure is associated with weight gain. The results are consistent with those studies that attribute postcessation weight gain to decreased metabolic activity and reduction in nicotine intake.

Pharmacological versus sensory factors in the satiation of chocolate craving

This is the first experimental study directed at differentiating between physiological or sensory accounts of the satiation of nondrug cravings, using chocolate craving, the most common craving in North America. At the onset of craving, chocolate cravers consumed a chocolate bar, the caloric equivalent in "white chocolate" (containing none of the pharmacological components of chocolate), the pharmacological equivalent in cocoa capsules, placebo, and no treatment conditions had virtually no effect. White chocolate produced partial abatement, unchanged by the addition of all the pharmacological factors in cocoa. This result indicates no role for pharmacological effects in the satisfaction of chocolate craving. It also suggests a role for aroma independent of sweetness, texture, and calories.

Weight change after smoking cessation in general practice

OBJECTIVE

To examine weight change among patients attending a smoking cessation program administered by general practitioners.

DESIGN

Body weight and smoking level were measured at the initial assessment and at a six-month follow-up visit. Pretreatment measures of demographic, attitudinal and smoking-related variables were examined for relationship to weight gain.

PARTICIPANTS

A total of 235 patients who were part of a smoking cessation study in Sydney.

MAIN OUTCOME MEASURE

Change in weight over six months.

RESULTS

Abstainers (n = 52) gained an average of 4.0 kg, significantly more than continuing smokers who gained an average of 1.2 kg. Among abstainers, only self-ratings of good health predicted weight gain.

CONCLUSIONS

Results indicate that weight gain among general practice patients following smoking cessation is similar to that in other research settings.