Trends in cigarette smoking among US adolescents, 1974 through 1991

Taking it to the streets: responses of African American young adults to internal tobacco industry documents

Since the Master Settlement Agreement of 1998 between 46 states and the major tobacco companies forced the release of over 30 million pages of previously secret internal tobacco industry documents, researchers have been exploring how information in the documents can be useful for advancing public health efforts. Previous research shows that the tobacco industry has made massive efforts to target marginalized communities, not only through typical advertising channels but also through establishing financial and other ties with influential leadership groups. However, no previous studies have explored how members of targeted groups might respond at the grassroots level to actual internal tobacco industry documents about such targeting. This exploratory focus group study, which invited urban African American participants to comment on previously secret internal tobacco industry documents, suggests that such documents may be useful in efforts to socially denormalize tobacco use, promote critical reflection about community targeting, and mobilize individuals toward quitting.

Childhood smoking is an independent risk factor for obstructive airways disease in women

OBJECTIVE

To assess whether starting to smoke in childhood increases the risk of obstructive airways disease (OAD) in adult life.

METHODS

A retrospective cohort analysis was undertaken of 12 504 current and ex-smokers in the EPIC-Norfolk cohort. The main exposure was starting to smoke during childhood (age <16 years). Three definitions of OAD were used: doctor diagnosed asthma, doctor diagnosed bronchitis/emphysema, and "any OAD" (doctor diagnosed asthma or bronchitis/emphysema, or taking medication used in the treatment of OAD).

RESULTS

Childhood smokers had significantly more pack years of exposure and poorer lung function than subjects who started to smoke in adulthood (>/=16 years). Compared with starting in adulthood, starting to smoke in childhood was associated with a greater risk of bronchitis/emphysema in female smokers (OR 1.79, 95% CI 1.25 to 2.56) and ex-smokers of both sexes (OR 1.29, 95% CI 1.07 to 1.55 in men and OR 1.40, 95% CI 1.05 to 1.85 in women), and of "any OAD" in female smokers (OR 1.72, 95% CI 1.24 to 2.38) and male and female ex-smokers (OR 1.20, 95% CI 1.03 to 1.40 in men and 1.34, 95% CI 1.07 to 1.57 in women). After adjustment for pack years, childhood smoking was associated with poorer lung function (FEV(1) 92.3% predicted in adult smokers and 89.5% in childhood smokers, p = 0.03) and a greater risk of bronchitis/emphysema (adjusted OR 1.55, 95% CI 1.08 to 2.24) and for "any OAD" (OR 1.54, 95% CI 1.10 to 2.13) in female smokers but not in male and female ex-smokers.

CONCLUSION

Starting to smoke in childhood is associated with an increased risk of airways disease because of the extra pack years smoked. In women, childhood smoking is itself an independent risk factor for the development of airways disease.

Cholinergic systems in brain development and disruption by neurotoxicants: nicotine, environmental tobacco smoke, organophosphates

Acetylcholine and other neurotransmitters play unique trophic roles in brain development. Accordingly, drugs and environmental toxicants that promote or interfere with neurotransmitter function evoke neurodevelopmental abnormalities by disrupting the timing or intensity of neurotrophic actions. The current review discusses three exposure scenarios involving acetylcholine systems: nicotine from maternal smoking during pregnancy, exposure to environmental tobacco smoke (ETS), and exposure to the organophosphate insecticide, chlorpyrifos (CPF). All three have long-term, adverse effects on specific processes involved in brain cell replication and differentiation, synaptic development and function, and ultimately behavioral performance. Many of these effects can be traced to the sequence of cellular events surrounding the trophic role of acetylcholine acting on its specific cellular receptors and associated signaling cascades. However, for chlorpyrifos, additional noncholinergic mechanisms appear to be critical in establishing the period of developmental vulnerability, the sites and type of neural damage, and the eventual outcome. New findings indicate that developmental neurotoxicity extends to late phases of brain maturation including adolescence. Novel in vitro and in vivo exposure models are being developed to uncover heretofore unsuspected mechanisms and targets for developmental neurotoxicants.

Developmental differences in nicotine place conditioning

To understand the motivations and implications of the prevalence of smoking, studies have compared the behavioral effects of nicotine, the psychoactive drug in tobacco, in adolescent and adult animals. The present study used a biased three-chambered conditioned-place preference procedure without prior habituation to examine the potential rewarding and anxiolytic effects of nicotine across adolescence and adulthood to assess the presence of age-dependent differences in response to nicotine.

Does prenatal nicotine exposure sensitize the brain to nicotine-induced neurotoxicity in adolescence?

Offspring of women who smoke during pregnancy are themselves more likely to take up smoking in adolescence. We evaluated neurotoxicant effects of prenatal and adolescent nicotine exposure in developing rats to evaluate whether these contribute to a biological basis for this relationship. Rats were given nicotine or vehicle throughout pregnancy and the offspring then again received nicotine or vehicle during adolescence (postnatal days PN30-47.5); this regimen reproduces the plasma nicotine levels found in smokers. Indices of neural cell number (DNA concentration and content), cell size (protein/DNA ratio), and cell membrane surface area (membrane/total protein) were then evaluated in brain regions during adolescent nicotine administration (PN45) and up to 1 month post-treatment. By itself, prenatal nicotine administration produced cellular alterations that persisted into adolescence, characterized by net cell losses in the midbrain and to a lesser extent, in the cerebral cortex, with corresponding elevations in the membrane/total protein ratio. The hippocampus showed a unique response, with increased DNA content and regional enlargement. Adolescent nicotine treatment alone had similar, albeit smaller effects, but also showed sex-dependence, with effects on protein biomarkers preferential to females. When animals exposed to nicotine prenatally were then given nicotine in adolescence, the net outcome was worsened, largely representing summation of the two individual effects. Our results indicate that prenatal nicotine exposure alters parameters of cell development lasting into adolescence, where the effects add to those elicited directly by adolescent nicotine; neurotoxicant actions may thus contribute to the association between maternal smoking and subsequent smoking in the offspring.

Genetics of Tobacco Use

The worldwide prevalence of tobacco use is widespread, resulting in nearly 4.5 million deaths every year. Nicotine is addictive and has psychopharmacological effects that maintain the use of tobacco products. Several studies have documented a strong hereditary component to tobacco use. The present article reviews results from twin and adoption studies and proceeds to present association studies of specific genes that may be involved in tobacco use. Cholinergic receptor nicotinic beta polypeptide 2, serotonin receptor and transporter genes, dopamine receptor and transporter genes, and the cytochrome P450A6 gene are reviewed. Linkage studies help to identify regions of the genome that may be worth further investigation. The paper concludes with a discussion of the limitations of genetic research and the future of genetic epidemiology in this domain.

Genetics of tobacco use

The worldwide prevalence of tobacco use is widespread, resulting in nearly 4.5 million deaths every year. Nicotine is addictive and has psychopharmacological effects that maintain the use of tobacco products. Several studies have documented a strong hereditary component to tobacco use. The present article reviews results from twin and adoption studies and proceeds to present association studies of specific genes that may be involved in tobacco use. Cholinergic receptor nicotinic beta polypeptide 2, serotonin receptor and transporter genes, dopamine receptor and transporter genes, and the cytochrome P450A6 gene are reviewed. Linkage studies help to identify regions of the genome that may be worth further investigation. The paper concludes with a discussion of the limitations of genetic research and the future of genetic epidemiology in this domain.

Prenatal nicotine exposure alters the response to nicotine administration in adolescence: effects on cholinergic systems during exposure and withdrawal

Maternal smoking during pregnancy increases the likelihood that the offspring will become smokers in adolescence. In the current study, we evaluated effects of prenatal and adolescent nicotine exposure in rats to assess whether there is a biological basis for this relationship. Pregnant rats were given nicotine or vehicle throughout pregnancy and the offspring then again received nicotine or vehicle during adolescence (postnatal days PN30-47.5), using a regimen (6 mg/kg/day by subcutaneous infusion) that produces plasma nicotine levels similar to those in smokers. Evaluations were made in the cerebral cortex and midbrain during adolescent nicotine administration (PN45) and for up to 1 month after the end of treatment. We assessed the magnitude and persistence of nicotinic acetylcholine receptor (nAChR) upregulation; in addition, we evaluated cholinergic synaptic activity by comparing the effects on choline acetyltransferase (ChAT), a constitutive marker for cholinergic nerve terminals, with those on hemicholinium-3 (HC-3) binding to the presynaptic choline transporter, which is regulated by nerve impulse activity. Prenatal nicotine exposure had only minor effects on nAChRs but produced persistent cholinergic hypoactivity (reduced HC-3 binding relative to ChAT) throughout adolescence and into adulthood (PN75). Adolescent nicotine exposure evoked robust nAChR upregulation and also suppressed cholinergic activity. Prenatal nicotine exposure reduced the upregulation of nAChRs evoked by adolescent nicotine but worsened the cholinergic hypoactivity during withdrawal. Our results indicate that prenatal nicotine exposure alters the subsequent response to nicotine in adolescence, effects that may contribute to the association between maternal smoking during pregnancy and subsequent adolescent smoking in the offspring.

Progression to established smoking among US youths

OBJECTIVES

Our study presents national estimates of the proportion of youths in each of 7 stages of smoking and investigates the associations between risk/protective factors and progression to established smoking.

METHODS

We analyzed data from the 1999 and 2000 National Youth Tobacco Surveys.

RESULTS

In 1999 and 2000, 48.6% of US adolescents had at least experimented with tobacco, and 7.8% were established smokers. Important correlates of progression to established smoking included parental advice not to smoke, antismoking lessons in school, susceptibility to tobacco industry advertising and promotion, peer smoking, and exposure to smoking at home.

CONCLUSIONS

Interventions to stop adolescent progression to established smoking should target susceptible never smokers and early experimenters as well as those in later stages of smoking.

From adolescence to young adulthood: racial/ethnic disparities in smoking

OBJECTIVES

We used data gathered from 6259 youths between the ages of 13 and 23 years to compare trends in smoking among 4 racial/ethnic groups.

METHODS

We weighted trend data to represent baseline respondent characteristics and evaluated these data with linear contrasts derived from multiple regression analyses.

RESULTS

Although African Americans exhibited higher initiation rates than Whites, they exhibited consistently lower rates of regular smoking than both Whites and Hispanics. This seeming anomaly was explained by African Americans' lower rates of transition to regular smoking and greater tendency to quit. Racial/ethnic disparities were accounted for by differences in pro-smoking influences.

CONCLUSIONS

Reducing racial/ethnic disparities in smoking may require reducing differences in the psychosocial factors that encourage smoking.

Racial/ethnic differences in cigarette smoking initiation and progression to daily smoking: a multilevel analysis

OBJECTIVES

We sought to identify individual and contextual predictors of adolescent smoking initiation and progression to daily smoking by race/ethnicity.

METHODS

We used data from the National Longitudinal Study of Adolescent Health to estimate the effects of individual (adolescent, family, peer) and contextual (school and state) factors on smoking onset among nonsmokers (n = 5374) and progression to daily smoking among smokers (n = 4474) with multilevel regression models.

RESULTS

Individual factors were more important predictors of smoking behaviors than were contextual factors. Predictors of smoking behaviors were mostly common across racial/ethnic groups.

CONCLUSIONS

The few identified racial/ethnic differences in predictors of smoking behavior suggest that universal prevention and intervention efforts could reach most adolescents regardless of race/ethnicity. With 2 exceptions, important contextual factors remain to be identified.

Neonatal ethanol exposure produces a hyperalgesia that extends into adolescence, and is associated with increased analgesic and rewarding properties of nicotine in rats

RATIONALE

Drug exposure during CNS development may alter subsequent dependence liability. We postulated that early alcohol exposure might produce persistent alterations in responses to noxious stimuli. Because relief of physical discomfort may be negatively reinforcing, changes in responses to noxious stimuli produced by early alcohol exposure may increase the rewarding properties of nicotine, a potent analgesic. Such factors may contribute to the high level of alcohol and nicotine co-abuse in humans.

OBJECTIVES

The purpose of this study was to determine whether neonatal ethanol exposure in rats altered responses to noxious stimuli, and whether nicotine would then be more rewarding to the alcohol-exposed offspring, perhaps via its analgesic actions.

METHODS

Neonatal rats received ethanol by gavage (5.0 or 6.5 g/kg) on postnatal days (PND) 9-13. An iso-caloric control group was also included. Rats were then tested to assess responsiveness to a mild noxious heat stimulus, as measured in the tail-flick assay (PND 14 and PND 28), for their response to acute analgesic injections of either nicotine or ethanol (PND 28), and for nicotine induced conditioned place preference (CPP) (PND 36).

RESULTS

Neonatal ethanol exposure produced hyperalgesia during the first 24 h after alcohol withdrawal (PND 14) that continued through PND 28. The analgesic effects of 12.5 microg/kg nicotine were enhanced approximately 2-fold in adolescent rats with previous ethanol histories, relative to controls. These ethanol-exposed rats also showed a significant CPP to nicotine, whereas controls showed no CPP.

CONCLUSIONS

Persistent decreases in tail-flick response latencies suggestive of hyperalgesia were observed following neonatal ethanol exposure in the rat. These changes were accompanied by increases in the analgesic and place-conditioning effects of nicotine in adolescence. If similar effects occur in humans, prenatal alcohol exposure may play a role in an increased risk for the rewarding effects and dependence liability of nicotine later in life.

Short-term adolescent nicotine exposure has immediate and persistent effects on cholinergic systems: critical periods, patterns of exposure, dose thresholds

In adolescents, the symptoms of nicotine dependence can appear well before the onset of habitual smoking. We investigated short-term nicotine exposure in adolescent rats for corresponding cholinergic alterations. Beginning on postnatal day 30, rats were given a 1-week regimen of nicotine infusions or twice-daily injections, at doses (0.6, 2, and 6 mg/kg/day) set to achieve plasma levels found in occasional to regular smokers. In the cerebral cortex, midbrain, and hippocampus, we assessed nicotinic cholinergic receptor (nAChR) binding, choline acetyltransferase (ChAT) activity, a constitutive marker for cholinergic nerve terminals, and [(3)H]hemicholinium-3 (HC-3) binding to the high-affinity choline transporter, which responds to cholinergic synaptic stimulation. nAChR upregulation was observed with either administration route, even at the lowest dose; in the hippocampus, increases could be detected with as little as 2 days' treatment at 0.6 mg/kg/day. In the midbrain, upregulation was still significant even 1 month post-treatment. Adolescent nicotine treatment also produced lasting decrements in HC-3 binding that were separable from effects on ChAT, suggesting cholinergic synaptic impairment. Again, these effects were obtained at the lowest dose and remained significant 1 month post-treatment. Our results indicate that in adolescence, even a brief period of continuous or intermittent nicotine exposure, elicits lasting alterations in cholinergic systems in brain regions associated with nicotine dependence. As the effects are detected at exposures that produce plasma concentrations as little as one-tenth of those in regular smokers, the exquisite sensitivity of the adolescent brain to nicotine may contribute to the onset of nicotine dependence even in occasional smokers.

Nicotine is a neurotoxin in the adolescent brain: critical periods, patterns of exposure, regional selectivity, and dose thresholds for macromolecular alterations

In the fetus, nicotine is a neuroteratogen that elicits cell damage and loss and subsequent abnormalities of synaptic function. We explored whether these effects extend into adolescence, the period when most people begin smoking. Beginning on postnatal day 30, rats were given a 1 week regimen of nicotine infusions or twice-daily injections, at doses (0.6, 2 and 6 mg/kg/day) set to achieve plasma levels found in occasional to regular smokers. We assessed indices of cell packing density and cell number (DNA concentration and content), cell size (total protein/DNA ratio) and neuritic projections (membrane/total protein) in the midbrain, hippocampus and cerebral cortex, three regions known to be vulnerable to developmental effects of nicotine. With either route of administration, nicotine evoked shortfalls in DNA concentration and content, compensatory elevations of total protein/DNA, and reductions in the membrane/total protein ratio. Nearly all of the effects were apparent even at the lowest dose of nicotine and remained fully evident 1 month posttreatment. Although both males and females showed significant alterations, in general the effects were larger in females. Our results indicate that in adolescence, even a brief period of continuous or intermittent nicotine exposure, elicits lasting alterations in biomarkers associated with cellular and neuritic damage. As the effects are detected at exposures that produce plasma concentrations one-tenth of those in regular smokers, the exquisite sensitivity of the adolescent brain to nicotine neurotoxicity may contribute to lasting neurobehavioral damage even in occasional smokers.

The history of adolescent medicine

The field of adolescent medicine is unique as a subspecialty in that the practice of providing care to teenagers has always been viewed historically as a responsibility of generalists. Scientific advances in subspecialty fields such as endocrinology, gynecology, gastroenterology, infectious disease, and sports medicine were incorporated with considerable success into the general practices of not only pediatricians but also internists and family practitioners. However, societal changes in the past century began to shape the way health professionals thought about adolescents and their families and significantly influenced the practice of providing health care to adolescents. The most notable change, however, was the shift from the traditional role of providing anticipatory guidance to parents toward a reduction of risk-taking behaviors aimed directly at the adolescent. The subspecialty of adolescent medicine thus emerged as an amalgam of researchers, clinicians, and educators, who, through a variety of settings, hoped to advance science, moderate public and social policy, improve health care, and stimulate health promotion to this special population of patients.

Constructing a short form of the Smoking Consequences Questionnaire with adolescents and young adults

The goal of the present studies was to construct and validate a short form of the 50-item Smoking Consequences Questionnaire (SCQ; T.H. Brandon & T. B. Baker, 1991), a measure of smoking outcome expectancies. In Study 1, a 21-item short form (S-SCQ) was derived from a sample of 107 young adults previously treated for substance abuse. In Study 2, the measure was cross-validated on 125 adolescents in treatment for substance abuse. Confirmatory factor analyses revealed good model fit and factorial invariance for the 4 S-SCQ subscales across both samples. Validation analyses on each sample found that subscale scores generally correlated significantly with smoking-related variables. The present studies provide initial evidence for the utility of the S-SCQ when used with young adults and adolescents.

Smoking differences among African American, Hispanic, and White middle school students in an urban setting

INTRODUCTION

Cross-sectional studies have repeatedly observed that African American adolescents are less likely to smoke when compared to White and Hispanic adolescents. Although much is known among high school samples, few scientifically based studies have reported these race and ethnic differences in cigarette smoking among younger samples.

METHODS

This study employed a secondary analysis of data from a 3-year middle school violence prevention project. The study design was a 3-year serial cross-sectional survey, out of which a cohort of students from sixth to eighth grade was formed. Smoking measurers were taken yearly.

RESULTS

8865 students responded in 1994, 9115 in 1995, and 9364 in 1996; 1589 students are in the 3-year cohort. Smoking prevalence rates from both measurement periods confirm the disparity between African Americans, Whites, and Hispanic youth. Although weak in sixth grade, by eighth grade, White and Hispanic students are smoking at two to four times the rate of their African American classmates.

CONCLUSIONS

Clearly, more etiological research needs to be conducted to understand the social, cultural, and intrapersonal forces that operate to inhibit the onset of smoking in African American youth and promote the onset of smoking in White and Hispanic youth.

Intervention to reduce intentions to use tobacco among pediatric cancer survivors

PURPOSE

In this randomized controlled trial, we sought to determine whether a risk counseling intervention would increase knowledge and perceived vulnerability to tobacco-related health risks and decrease future intentions to use tobacco among preadolescents and adolescents previously treated for cancer.

PATIENT AND METHODS

Participants included 103 cancer survivors between the ages of 10 and 18 years who were randomly assigned to either a standard care control (SCC) group or a tobacco intervention (TI) group. Patients in the SCC group received standard advice about the risks of tobacco use. Patients in the TI group received more intensive late effects risk counseling in addition to an educational video, goal setting, written physician feedback, smoking literature, and follow-up telephone counseling. The effect of our intervention was assessed by self-reported knowledge, perceived vulnerability, and intentions at baseline, 6, and 12 months.

RESULTS

Compared with the SCC group, patients who received our intervention had significantly higher knowledge scores, higher perceived vulnerability scores, and lower intention scores at 12 months. No significant differences between the SCC and TI groups at 6 months, across all measures, were found.

CONCLUSION

Pediatric survivors' knowledge, perceived vulnerability to health risks, and intentions to use tobacco can be modified by a risk counseling intervention. The delayed effect of our intervention indicates that these changes may evolve over time. Implications for health care providers who engage in tobacco counseling with young cancer survivors are discussed. Additional longitudinal studies are needed to determine definitive long-term intervention effects on actual tobacco use in this high-risk population.

Adolescent nicotine administration alters serotonin receptors and cell signaling mediated through adenylyl cyclase

Nicotine is a neuroteratogen that targets synaptic function during critical developmental stages and recent studies indicate that CNS vulnerability extends into adolescence, the age at which smoking typically commences. We administered nicotine to adolescent rats via continuous minipump infusions from PN30 to PN47.5, using 6 mg/kg/day, a dose rate that replicates the plasma nicotine levels found in smokers, and examined 5HT receptors and related cell signaling during nicotine administration (PN45) and in the post-treatment period (PN50, 60, 75). Adolescent nicotine decreased 5HT(2) receptor binding in brain regions containing 5HT projections (hippocampus and cerebral cortex), with selectivity for females in the cerebral cortex; regions containing 5HT cell bodies showed either an increase (midbrain in males) or no change (brainstem). In contrast, there were no significant changes in 5HT(1A) receptors; however, the ability of the receptors to signal through adenylyl cyclase (AC) showed a switch from stimulatory to inhibitory effects in females during the post-treatment period. There were also transient alterations in AC responses to beta-adrenergic receptor stimulation, as well as pronounced induction of the AC response to the non-receptor-mediated stimulant, forskolin. Our results indicate that adolescent nicotine exposure alters the concentrations and functions of postsynaptic 5HT receptors in a manner commensurate with impaired 5HT synaptic function. The direction of change, emergence of defects after the cessation of nicotine administration, and sex-preference for effects in females, all support a relationship of impaired 5HT function to the higher incidence of depression seen in adolescent smokers.

Smoking habits and attitudes towards smoking among university students in Jordan

The aim of this study was to estimate the prevalence of smoking and to describe the habits, attitudes, and practices related to smoking among students of Jordan University of Science and Technology (JUST), Irbid, Jordan. Students (n = 650) were recruited in randomly selected, cluster samples drawn from the medical and engineering colleges of JUST. They were made familiar with a modified Arabic version of the World Health Organisation Smoking Questionnaire and the Attitudes towards Smoking Questionnaire to study their habits, attitudes, and beliefs in relation to smoking. The study revealed that the prevalence of smoking was 28.6% (50.2% among males and 6.5% among females). Friends, not family, were the main source of the first smoking, and this most often occurred after 15 years of age (82.3%). Males preferred smoking in the cafeteria, females in the bathroom. The main advantage of smoking for males was calming down, while for females it was independence. Non-smokers chose not to smoke because of health and hatred of the habit. The non-smokers had more positive attitudes against smoking and were more aware of the adverse effects of smoking. The reasons smokers gave for starting smoking were pleasure, followed by stress and curiosity. Two-thirds of smokers intended to quit smoking in the future. Some smokers disagreed with some criticisms against smoking, and reasons why they did not want to quit included social attitudes, addiction, and not knowing how to quit. Results of this study may provide baseline data to develop an anti-smoking program in the university and encourage policy makers to limit smoking in the university by strengthening the policies against smoking.

Applying genetic approaches to the treatment of nicotine dependence

To advance the science of tobacco control, an enhanced understanding of the bio-behavioral basis of nicotine addiction is needed. In this study, we provide an overview of data from investigations of genetic factors in smoking behavior, discuss potential bio-behavioral mechanisms and effect modifiers, and suggest avenues for pharmacogenetics research in the area of smoking cessation treatment. The evidence to date is very consistent with respect to the significance of genetic contributions to smoking behavior. However, attempts to elucidate the role of specific genetic variants have met with mixed success. Explanations for the lack of consistency in the results of genetic association studies include biases in ascertainment, ethnic admixture, lack of attention to co-variates or modifiers of genetic risk, and the need for more refined phenotypes. As the field of genetics and smoking research progresses, increasing attention is being devoted to gene-environment interactions, with particular attention to the identification of genetic variants that may modify the effects of pharmacological treatment for smoking. With advances in molecular biology and genomics technology, individualized tailoring of smoking cessation therapy to genotype is within our grasp. Such research has the potential to improve treatment outcome, thereby reducing morbidity and mortality from smoking-related disease.

Nicotine-induced conditioned place preference in adolescent and adult rats

About 1 million American adolescents start smoking every year. Adolescents may be unusually sensitive to certain consequences of nicotine, demonstrating, for instance, significantly higher rates of dependence than adults at the same level of nicotine use. To explore whether adolescents may be more sensitive to rewarding properties of nicotine than adults, the present study used an animal model to assess the rewarding effects of a low nicotine dose (0.6 mg/kg) in a conditioned place preference (CPP) paradigm. Locomotor activity during conditioning and testing was also evaluated. Nicotine was observed to induce place preference conditioning in adolescent Sprague-Dawley rats, whereas the training dose of 0.6 mg/kg failed to produce convincing place preference in their adult counterparts. Age differences were also apparent in terms of nicotine influences on motor activity, with adults being more sensitive to nicotine-suppressant effects and only adolescents showing an emergence of nicotine-stimulatory effects upon repeated exposures. An increased predisposition to stimulatory nicotine effects during adolescence may contribute to age-specific rewarding properties of the drug as revealed using the CPP paradigm in this experiment. Increased sensitivity to stimulatory and rewarding effects during adolescence could potentially contribute to the high rate of nicotine use and dependence among human adolescents.

Television viewing and initiation of smoking among youth

BACKGROUND

Smoking is the leading preventable cause of death in the United States, and the risk of disease increases the earlier in life smoking begins. The prevalence of smoking among US adolescents has increased since 1991. Despite bans on television tobacco advertising, smoking on television remains widespread.

OBJECTIVE

To determine whether youth with greater exposure to television viewing exhibit higher rates of smoking initiation.

METHODS

We used the National Longitudinal Survey of Youth, Child Cohort to examine longitudinally the association of television viewing in 1990 among youth ages 10 to 15 years with smoking initiation from 1990-1992. Television viewing was based on the average of youth and parent reports. We used multiple logistic regression, taking into account sampling weights, and controlled for ethnicity; maternal education, IQ, and work; household structure; number of children; household poverty; child gender; and child aptitude test scores.

RESULTS

Among these youth, smoking increased from 4.8% in 1990 to 12.3% in 1992. Controlling for baseline characteristics, youth who watched 5 or more hours of TV per day were 5.99 times more likely to initiate smoking behaviors (95% confidence interval: 1.39-25.71) than those youth who watched <2 hours. Similarly, youth who watched >4 to 5 hours per day were 5.24 times more likely to initiate smoking than youth who watched <2 hours (95% confidence interval: 1.19-23.10).

CONCLUSIONS

Television viewing is associated in a dose-response relationship with the initiation of youth smoking. Television viewing should be included in adolescent risk behavior research. Interventions to reduce television viewing may also reduce youth smoking initiation.

Early predictors of daily smoking in young women: the national heart, lung, and blood institute growth and health study

BACKGROUND

Smoking is highly prevalent in young women and little is known about early multilevel independent risk or protective factors that are predictive of daily smoking in young women.

METHODS

Multiple logistic regression was conducted on data from NGHS, a 10-year cohort study of Black (1,213) and White (1,166) girls recruited from three clinical centers in the United States, ages 9-10 years on entry to ages 18-19.

RESULTS

Compared with never smokers, White girls were at higher risk than Black girls of being daily smokers at ages 18-19. Early predictors of daily smoking at ages 18-19 years included lower parental education, one parent in the household, drinking alcohol at ages 11-12, higher drive for thinness at ages 11-12, lower behavioral conduct at ages 11-12, and lower stress at ages 10-11 and higher stress at ages 12-13. For both Black and White girls weight-related variables were significant. Stress, behavioral conduct, and one-parent household were also important predictors for White girls.

CONCLUSIONS

There is evidence that childhood and adolescent factors are related to young adult smoking behavior. Body weight concerns as well as family, social environment, and behavioral factors are important issues in determining which girls will become daily smokers.

Adolescent nicotine: deficits in immune function

Maternal cigarette smoking during pregnancy is known to alter immune function in the offspring and recent studies with animals indicate that prenatal nicotine exposure leads to lasting deficiencies in T-lymphocyte mitogenic responses, likely through excessive cholinergic stimulation during a critical stage of development. The current study was conducted to determine if the vulnerable period for nicotine-induced mis-programming of immune responses extends into adolescence, the stage at which most smokers begin tobacco use. Adolescent rats were given nicotine via osmotic minipump infusions on postnatal days (PN) 30-47.5, using a regimen that produces plasma levels (25 ng/ml) of nicotine similar to those in smokers or in users of transdermal nicotine patches. Toward the end of the infusion period (PN45) and 1 month after termination of nicotine exposure (PN80), we examined the mitogenic responses of splenocytes to Concanavalin A. Although no deficiencies were seen on PN45, there were robust decreases in mitogenic responses on PN80, with deficits apparent at both suboptimal and optimal concentrations of Concanavalin A. These results indicate that the adolescent immune system is vulnerable to nicotine-induced disruption of T-cell function.

Characterization of the smoking habit among high school students in Syria

OBJECTIVES

To establish an accurate estimate of the prevalence of smoking among high school students in Aleppo-Syria and to characterize the smoking habit in this age group.

DESIGN

A cross-sectional survey was performed, in which a self-administered questionnaire was distributed to 10th, 11th and 12th graders.

SUBJECTS

A sample of 1587 students (784 males; mean age 16 years, and 803 females; mean age 15.9 years) was studied. This sample was drawn from 16 schools randomly selected from a total of 73 schools in the city.

RESULTS

The prevalence of current smoking was 15.9% for males and 6.6% for females. The prevalence of daily smoking was 2.4% for males and 0.5% for females. Almost all smoking categories increased with age and grade. Forty seven percent of male daily smokers were heavy smokers. Peer influence was evident in all stages of the smoking process, especially for males. Parental smoking was also an important associated factor. The combination of parental and siblings smoking was the strongest predictor of the smoking status of the surveyed (OR: 4.4; 95% CI: 2.7-7). Thirty eight percent of male smokers and 47.2% of female smokers smoke out of boredom. Fifty one percent of male smokers were introduced to smoking by a friend. Forty percent of male smokers buy their cigarettes, while 56.6% of female smokers obtain their cigarettes from home. Logistic regression analyses showed that parental and siblings smoking were the most important predictors of ever trying to smoke or current smoking among male and female students.

CONCLUSIONS

Our study shows that smoking is more frequent in male than female students. Parental and sibling smoking are the most important factors associated with smoking in this population, and peer influence is important particularly in the smoking-initiation stage. Pattern of smoking and associated factors differed substantially between males and females in this study.

The association between cigarette smoking and drug abuse in the United States

Cigarette smoking has been identified as an independent risk factor for many human diseases. However, the association between cigarette smoking and illegal drug use has not been thoroughly investigated. We have analyzed the 1994 National Household Survey on Drug Abuse to clarify whether cigarette smoking has any effect on the initiation of illegal drug use. Data from 17,809 respondents completing the 1994 "new" (1994-B) questionnaire were analyzed. Logistic regression analyses were performed with the use of statistical package SUDAAN, taking into consideration the multistage sampling design. The results show that those who had smoked cigarettes were far more likely to use cocaine (OR = 7.5; 95% CI: 5.7-9.9), heroin (OR = 16.0; 95% CI: 6.8-37.9), crack (OR = 13.9; 95% CI: 7.9-24.5) and marijuana (OR = 7.3; 95% CI: 6.2-8.7). The associations are consistent across age-strata and remain after adjusting for race and gender. This study suggests that cigarette smoking may be a gateway drug to illegal drug use.

High-risk behaviors associated with early smoking: results from a 5-year follow-up

PURPOSE

To compare grade 7 nonsmokers, experimenters, and smokers on the basis of prevalence of other problem behaviors at both grade 7 and grade 12.

METHODS

Based on longitudinal self-report data from 4327 California and Oregon students, we used logistic regression to develop weighted estimates of the prevalence of academic difficulties, substance use, and delinquent behavior within the three smoking status groups at grades 7 and 12. Huber variance estimates, which adjust for weighting and clustering of observations, were used to assess the statistical significance of differences across groups.

RESULTS

Compared with nonsmokers, early smokers were at least 3 times more likely by grade 12 to regularly use tobacco and marijuana, use hard drugs, sell drugs, have multiple drug problems, drop out of school, and experience early pregnancy and parenthood. These adolescents were also at higher risk for low academic achievement and behavioral problems at school, stealing and other delinquent behaviors, and use of predatory and relational violence. Early experimenters were at significantly greater risk for these problems as well, although to a lesser extent than smokers. Importantly, the higher risk among experimenters and smokers of experiencing many of these problems was evident as early as grade 7.

CONCLUSIONS

Early experimenters and smokers are more likely than nonsmokers to experience various problem behaviors by grade 12, with many of these problems evident as early as grade 7. Results suggest that substance use programs that target multiple problems in addition to smoking may be most effective for these high-risk adolescents.

Sources of information on the health effects of environmental tobacco smoke among African-American children and adolescents

PURPOSE

To determine the common sources of information regarding the effects of smoking on health and their relationship to knowledge, attitudes, and preventative efforts regarding exposure to environmental tobacco smoke (ETS) among urban African-American children and adolescents.

METHODS

All students who were enrolled in Grades 5-12 in an urban public school district located in the greater metropolitan area of Detroit, Michigan were surveyed using a structured, written questionnaire that assessed sources of information on the health effects of smoking, as well as knowledge, attitudes, and preventive efforts with respect to exposure to ETS. The primary analytic procedures utilized in the study were correlation analysis and analysis of variance.

RESULTS

The African-American students surveyed in this study received information regarding the health effects of smoking from many sources, most notably television, family, and teachers. Second, students who received information on the effects of smoking on health from family and external sources (teacher, parent's friend, and religious leader) had higher overall knowledge, attitude, and preventive efforts scores than students who received information from other sources (friends, electronic media, and printed media). Finally, family influence was greater when parents were not smokers, and influenced elementary students more than middle school or high school students.

CONCLUSIONS

The active involvement of teachers, religious leaders, parents, and other influential adults should be elicited in tobacco education and prevention efforts to maximize their effectiveness.

Smoking in adolescence do attitudes matter?

A number of factors have emerged as being associated with adolescent smoking. While theoretical evidence suggests that attitude can be an important factor influencing smoking, empirical findings are somewhat contradictory. The main goal of the present study has been to identify the characteristics/dimensions of attitudes toward smoking in adolescence. Data were collected among primary (Grades 7-8), and secondary (Grades 9-12) school students using randomly selected classes in Szolnok, Hungary (N= 261). The self-administered questionnaire consisted of questions on sociodemographics, smoking behavior, beliefs, and attitudes related to smoking (items adapted from The Students' Health and Lifestyle Study developed by the research team of The University of Western Ontario, Canada). Factor analysis of the statements concerning smoking gave five factors: antismoking attitude, liking attitude, worrying attitude, disliking attitude, and unrealistic attitude. Antismoking attitude proved to be the most important influencing factor of tobacco use, which was greatly independent from the number of smoking friends in boys and older adolescents. However, peer smoking could definitely moderate this attitude and thus the linkage between attitude and smoking activity in girls and younger adolescents. Our findings support the idea that antismoking interventions can be adapted to the target groups as programs may have different impact on boys and girls and on different age groups.

Epidemiology of tobacco use among US adolescents

Among persons in the United States under age 18 years, every day more than 6000 try cigarette smoking for the first time and more than 3000 become daily smokers. The overwhelming majority of adults who smoke began by age 18 years. Slightly more than one-third of US high school students were cigarette smokers in 1997. In recent years, males were about as likely as females to smoke. American Indians/Alaska Natives and whites were more likely to smoke than were Hispanics, African-Americans, and Asian-Americans/Pacific Islanders. Overall, cigarette smoking prevalence declined in the late 1970s or early 1980s, leveled off in the 1980s, and increased in the 1990s. The decline in prevalence among African-Americans was especially noteworthy. Among US high school students in 1997, the prevalence of cigar smoking was higher than that of smokeless tobacco use. Indicators of nicotine dependence are prevalent among adolescents who use tobacco products. Efforts to: (1) improve the validity of self-reported behaviors; (2) increase access to school dropouts and infrequent school attendees; and (3) improve school participation rates, data availability, and data linkage systems will benefit the field. Qualitative research can suggest variables to be added to survey questionnaires. Methods research should be conducted to better quantify and explain differences between survey estimates. Tracking relevant environmental variables and new tobacco products will expand the science base and facilitate appropriate public health action.

Adolescent nicotine exposure produces immediate and long-term changes in CNS noradrenergic and dopaminergic function

Animal studies have only recently begun to address whether nicotine evokes unique or persistent effects on brain structure or function during adolescence, the period in which smokers typically begin their habit. In the current study, we examined the impact of adolescent nicotine treatment on catecholaminergic synaptic function in rats infused with nicotine on postnatal days 30-47.5, using a paradigm that reproduces the plasma levels of nicotine found in smokers. We assessed norepinephrine and dopamine content, turnover (an index of neural activity), and the response to an acute challenge dose of nicotine. In the midbrain, the region most closely associated with addiction, both norepinephrine and dopamine turnover were activated during the infusion period, an effect not seen in any other region for norepinephrine, and only in the striatum for dopamine. In the immediate post-infusion period (PN50-60), there was a decrement in midbrain catecholamine turnover restricted to males, whereas there was a later-emerging (PN80) activation of these pathways. Again, this pattern was not observed in any other region: the cerebral cortex showed post-treatment increases in turnover without gender selectivity, the striatum showed late-emerging deficits in dopamine turnover and the hippocampus displayed a profound deficit in noradrenergic activity that was limited to females. We also assessed the catecholaminergic response to an acute challenge with nicotine (0.3 mg/kg s.c.). The midbrain once more displayed unique properties; there was initial suppression of responses followed by post-treatment rebound elevations that were more prominent in males and eventual deficits that, in the case of dopamine, were selective for males. With the exception of the cerebellum, other regions showed the initial loss of response during the infusion period but no persistent changes in responsiveness. The current results indicate that adolescent nicotine produces immediate and long-term changes in CNS catecholaminergic systems, with regional targeting and gender selectivity corresponding to the changes seen previously in nicotinic receptor upregulation or indices of cell damage. These effects may underlie long-term behavioral changes associated with adolescent nicotine exposure.

Cigarette use in adolescents: the Cardiovascular Health in Children and Youth Study

Tobacco is the leading cause of preventable death in the United States, and its use is increasing in adolescents. To determine the interventions needed to prevent the initiation of smoking, it is important to know the factors related to tobacco use by adolescents. In this study the following factors related to cigarette use were examined: age, gender, ethnicity, self-esteem, physical activity, parental smoking, and socioeconomic status. Participants were 1,207 youth completing a written survey for the Cardiovascular Health in Children and Youth Study (CHIC II). Participants ranged in age from 10 to 15 years, with a mean age of 12.2 years; 64.2% were White, 24.0% Black, 5.8% Hispanic, and 6.0% other races. White and Hispanic youth and youth of other races had significantly higher rates of smoking than did Black youth. Significant risk factors for smoking were: higher grade in school, White race, and for girls only, lower self-esteem. In White youth those in the lowest socioeconomic status were most likely to be current and experimental smokers. Smoking was as common in girls as in boys at these ages. Multivariate analysis showed that neither physical activity nor parental smoking were significant predictors of smoking behaviors. These results suggest that smoking prevention programs for adolescents should specifically target White and Hispanic youth and those from families with low socioeconomic status. In addition, these interventions should include ways to increase self-esteem in girls.

Persistent and delayed behavioral changes after nicotine treatment in adolescent rats

Despite the increasing use of tobacco by adolescents, few animal studies have addressed the neurobehavioral consequences of nicotine exposure during this period. We administered nicotine to adolescent rats via continuous infusion on postnatal days (PN) 30 through 47.5, using a dosage regimen that maintains plasma levels similar to those found in smokers or in users of the transdermal nicotine patch. Behavior in a novel open field and learning a passive avoidance task were assessed during nicotine treatment and for 2 weeks post-treatment. On PN44, during nicotine exposure, female rats showed decreased grooming, an effect not seen in males; this effect is opposite to the effects of nicotine in adult rats. Two weeks after cessation of nicotine administration, females showed deficits in locomotor activity and rearing, whereas males again were unaffected; the behavioral deficits appeared at the same age at which gender-selective brain cell damage emerges. In contrast, nicotine exposure enhanced passive avoidance, with the effect intensifying and persisting throughout the post-treatment period. These results reinforce the concept that developmental vulnerability to nicotine extends into adolescence, with patterns of drug effects different from those in earlier or later periods. The correlation of neurochemical with behavioral effects strengthens the connection between adolescent nicotine exposure and persistent functional changes that may influence drug habituation, learning and memory.

Psychosocial determinants of the onset and escalation of smoking: cross-sectional and prospective findings in multiethnic middle school samples

PURPOSE

To investigate a broad range of social influence-related and global determinants of smoking to aid in the design of comprehensive multiethnic interventions by testing the most important factors of initiation and escalation of smoking across various subgroups.

METHODS

Cross-sectional (N = 2546) and cohort (N = 736) samples of multiethnic middle school students near a large Southwestern metropolis were surveyed through self-report questionnaires. The confidential questionnaires included information on demographics, risk factors, and smoking behavior and were administered in class by trained data collectors. Multivariable logistic regression analysis was used to examine the statistical significance and strength of the factors.

RESULTS

Those lower in self-esteem and higher in social assertiveness appeared to be most at risk for the onset of smoking, whereas those low in optimism appeared to be the most at risk for the escalation of smoking. Attitudes, friends' norms, parents' norms, perceived behavioral control, and perceived prevalence were consistent predictors of all smoking status outcomes.

CONCLUSIONS

The behavioral-specific determinants of smoking appear to be important predictors of smoking status outcomes in all demographic subgroups. The relationships of the global determinants were more dependent on the smoking outcome variable and subgroup examined. The findings may serve to help facilitate the targeting of comprehensive interventions aimed at reducing adolescent smoking in multiethnic and ethnic group-specific populations.

Adolescent smoking cessation: how effective have we been?

Adolescent smoking, at its current rate, is considered a pediatric epidemic, with 3,000 youths less than 18 years of age becoming regular smokers each day (Johnson, O'Malley, & Bachman, 1998). The reasons adolescents begin and continue to smoke are multifactorial. There is a paucity of research describing effective adolescent smoking-cessation programs. Much of the research on adolescent tobacco use has focused on correlates and prevention of onset, rather than on intervention with active smokers. Current research indicates that 75% of adolescents who currently smoke want to quit. It is essential that nurses involved with adolescent health promotion become active in smoking-cessation efforts. This article describes the risk factors for adolescent smoking and identifies smoking-cessation strategies, with interventions specific to the adolescent population.

Adolescent nicotine exposure alters cardiac autonomic responsiveness: beta-adrenergic and m2-muscarinic receptors and their linkage to adenylyl cyclase

Recent work indicates that adolescent smokers have an abnormally high incidence of heart rate irregularities. In the current study, adolescent rats received nicotine by continuous infusion from postnatal days (PN) 30-47.5, using a regimen designed to produce plasma levels found in smokers. We then assessed the levels of cardiac beta-adrenergic and m2-muscarinic cholinergic receptor binding, and receptor linkages to adenylyl cyclase activity, during nicotine exposure and for 1 month afterwards. In the nicotine-exposed group, m2-receptors showed a significant reduction that persisted through PN75, 1 month after the termination of treatment. beta-Receptors showed a tendency toward initial suppression and subsequent elevation. The receptor changes were accompanied by corresponding alterations in the response of adenylyl cyclase to carbachol and isoproterenol: the inhibitory muscarinic response was reduced, so that the net response to combined treatment with carbachol and isoproterenol was enhanced. There were additional changes in basal and forskolin-Mn(2+)-stimulated adenylyl cyclase activity suggestive of shifts in enzymatic catalytic properties. The effects of adolescent nicotine exposure were distinct from those seen previously with fetal nicotine treatment. In light of the worldwide increase in tobacco use by teenagers, these studies raise concern that cardiovascular function may be especially vulnerable during this critical period.

Modeling adolescent nicotine exposure: effects on cholinergic systems in rat brain regions

Smoking among teenagers is increasing and the initiation of tobacco use during adolescence is associated with subsequently higher cigarette consumption and lower rates of quitting. Few animal studies have addressed whether adolescent nicotine exposure exerts unique or lasting effects on brain structure or function. Initial investigations with a rat model of adolescent nicotine exposure have demonstrated that the vulnerable developmental period for nicotine-induced brain cell damage extends into adolescence. In the current study, we examined the effect of nicotine on cholinergic systems in male and female adolescent rats with an infusion paradigm designed to match the plasma levels found in human smokers or in users of the transdermal nicotine patch. Choline acetyltransferase activity (ChAT) and [3H]hemicholinium-3 binding (HC-3) were monitored; ChAT is a static marker that closely reflects the density of cholinergic innervation, whereas HC-3 binding, which labels the presynaptic high-affinity choline transporter, is responsive additionally to nerve impulse activity. Measurements were carried out in the midbrain, the region most closely involved in reward and addiction pathways, as well as in the cerebral cortex and hippocampus. During nicotine treatment and for 1 month after the termination of treatment, ChAT activity was reduced significantly in the midbrain but not in the other regions. HC-3 binding showed a substantial increase during the course of nicotine treatment and again, the effect was limited to the midbrain. Midbrain values returned to normal immediately after the cessation of nicotine exposure and then showed a subsequent, transient suppression of activity. Although the cerebral cortex showed little or no change in HC-3 binding during or after nicotine administration, activity was reduced persistently in the hippocampus. The regionally-selective effects of adolescent nicotine treatment on cholinergic systems support the concept that adolescence is a vulnerable developmental period for ultimate effects on behavior.

An animal model of adolescent nicotine exposure: effects on gene expression and macromolecular constituents in rat brain regions

Nearly all smokers begin tobacco use in adolescence, and approximately 25% of US teenagers are daily smokers. Prenatal nicotine exposure is known to produce brain damage, to alter synaptic function and to cause behavioral anomalies, but little or no work has been done to determine if the adolescent brain is also vulnerable. We examined the effect of adolescent nicotine exposure on indices of cell damage in male and female rats with an infusion paradigm designed to match the plasma levels found in human smokers or in users of the transdermal nicotine patch. Measurements were made of DNA and protein as well as expression of mRNAs encoding genes involved in differentiation and apoptosis (p53, c-fos) in cerebral cortex, midbrain and hippocampus. Following nicotine treatment from postnatal days 30-47.5, changes in macromolecular constituents indicative of cell loss (reduced DNA) and altered cell size (protein/DNA ratio) were seen across all three brain regions. In addition, expression of p53 showed region- and gender-selective alterations consistent with cell damage; c-fos, which is constitutively overexpressed after gestational nicotine exposure, was unaffected with the adolescent treatment paradigm. Although these measures indicate that the fetal brain is more vulnerable to nicotine than is the adolescent brain, the critical period for nicotine-induced developmental neurotoxicity clearly extends into adolescence. Effects on gene expression and cell number, along with resultant or direct effects on synaptic function, may contribute to increased addictive properties and long-term behavioral deficits.

Prevalence and correlates of smokeless tobacco use in a sample of Connecticut students

We examined the prevalence of smokeless tobacco use, and its relationship to other risky behaviors in Connecticut school children in grades four through 12 (n=31,861). Less than one per cent of students in grades 4-8, and four per cent of those in grades 9-12, used smokeless tobacco. Eighty-two percent of all users were white males. Among high school males, the prevalences of risk-taking behaviors and feelings of stress and depression were significantly higher among users than non-users. Among high school males, the highest prevalences of risky behaviors and stress indicators were reported by joint users of cigarettes and smokeless tobacco.

Trends in adult cigarette smoking in California compared with the rest of the United States, 1978-1994

OBJECTIVES

This study compared trends in adult cigarette smoking prevalence in California and the remainder of the United States between 1978 and 1994.

METHODS

We used data from National Health Interview Surveys and Behavioral Risk Factor Surveillance System surveys to compare trends in smoking prevalence among persons 18 years and older.

RESULTS

In both California and the remainder of the United States, the estimated annual rate of decline in adult smoking prevalence accelerated significantly from 1985 to 1990: to -1.22 percentage points per year (95% confidence interval [CI] = -1.51, -0.93) in California and to -0.93 percentage points per year (95% CI = -1.13, -0.73) in the remainder of the nation. The rate of decline slowed significantly from 1990 to 1994: to -0.39 percentage points per year (95% CI = -0.76, -0.03) in California and to -0.05 percentage points per year (95% CI = -0.34, 0.24) in the remainder of the United States.

CONCLUSIONS

The presence of an aggressive tobacco control intervention has supported a significant decline in adult smoking prevalence in California from 1985 to 1990 and a slower but still significant decline from 1990 to 1994, a period in which there was no significant decline in the remainder of the nation. To restore nationwide progress in reducing smoking prevalence, other states should consider similar interventions.

Exposure of black youths to cigarette advertising in magazines

OBJECTIVE

To estimate the potential exposure of black adolescents to brand specific advertising in magazines.

DESIGN

A probit regression analysis was conducted of pooled 1990 and 1994 data on brand specific advertising in 36 popular US magazines to examine the relationship between the presence or absence of advertising in each magazine for each of 12 cigarette brands, and the proportion of each magazine's youth (ages 12-17 years) readers who were black.

MAIN OUTCOME MEASURES

The presence or absence of advertising in each magazine in 1990 and 1994, for each of 12 cigarette brands.

RESULTS

After controlling for total magazine readership and the percentage of young adult, Hispanic, and female readers, black youth cigarette brands (those whose market share among black youths exceeded their overall market share) were more likely than other brands to advertise in magazines with a higher percentage of black youth readers. Holding all other variables constant at their sample means, the probability of a non-black youth brand advertising in a magazine decreased over the observed range of percentage black youth readership from 0.65 (95% confidence interval (CI) 0.55 to 0.75) for magazines with 5% black youth readers to 0.33 (95% CI 0.00 to 0.69) for magazines with 91% black youth readers. In contrast, the probability of a black youth brand advertising in a magazine increased from 0.40 (95% CI 0.17 to 0.62) at 5% black youth readership to 1.00 (95% CI 0.97 to 1.00) at 91% black youth readership.

CONCLUSIONS

Black youths are more likely than white youths to be exposed to magazine advertising by cigarette brands popular among black adolescents.

Substance use in high school students in New South Wales, Australia, in relation to language spoken at home

PURPOSE

To examine for the first time adolescent substance use by ethnicity, given the high proportion of migrants from non-English-speaking countries in New South Wales, (NSW), Australia.

METHODS

Data from four surveys of NSW secondary school students in 1983, 1986, 1989, and 1992 were used for this analysis. The prevalence of substance use by whether English was spoken at home was stratified by sex and age using data from the most recent survey year. Adjusted odds ratios and 95% confidence intervals were produced by simultaneous logistic regression, adjusting for sex, age group, and the interaction term of sex and age for each of these substances, and for each survey year separately. Data from 1989 and 1992 were pooled together to examine rates of substance use by ethnic subgroups which reflect migration patterns.

RESULTS

The prevalence of smoking and alcohol and illicit drug use was consistently lower among NSW adolescents speaking a language other than English at home, compared with those speaking English at home in all survey years. Only the prevalence of solvent sniffing was higher among younger adolescents speaking a language other than English at home. Students from Southeast Asia showed consistently lower rates of usage of all substances compared to all other groups.

CONCLUSIONS

There may be different opportunities for the prevention of adolescent substance use among native English speakers to be gained from non-English-speaking cultures.

Adolescent nicotine exposure causes persistent upregulation of nicotinic cholinergic receptors in rat brain regions

Whereas numerous studies have explored the consequences of fetal or adult nicotine exposure, little or no basic research has been conducted for nicotine exposure during adolescence, the developmental period in which regular cigarette use typically begins. We administered nicotine to adolescent rats on postnatal days 30-47 via continuous infusion with implanted osmotic minipumps, using a dose rate (3-6 mg kg-1 day-1) set to achieve plasma nicotine levels found in smokers; results were compared to exposure of adult rats. During and after exposure, we assessed nicotinic cholinergic receptor binding in the midbrain, cerebral cortex, and hippocampus, using [3H]cytisine. Robust receptor upregulation was observed with both adolescent and adult nicotine exposure but there were major differences in the regional specificity and persistence of effect. In adolescents, upregulation was uniform across all regions during the infusion period, whereas in adults, there was a distinct regional hierarchy: midbrain < cerebral cortex < hippocampus; accordingly, receptors in the adolescent midbrain were upregulated far more than with adult exposure. In addition, adolescent nicotine treatment produced long-lasting effects on the receptors, with significant increases still apparent in male rats 1 month after the termination of drug exposure. We also obtained evidence for hippocampal cell damage in adolescent female rats exposed to nicotine, characterized by increases in total membrane protein concentration indicative of a decrease in overall cell size. Adolescent nicotine exposure thus elicits region- and gender-selective effects that differ substantially from those in adults, effects that may contribute to increased addictive properties and lasting deficits in behavioral performance.

Primordial prevention of cardiovascular disease among African-Americans: a social epidemiological perspective

BACKGROUND

The primordial prevention of cardiovascular disease (CVD) among African-Americans represents a formidable challenge for public health. This paper discusses the nature of this challenge, highlighting the role that economic and cultural factors play in shaping the distributions of major CVD risk factors among African-Americans. The paper concludes with specific suggestions for research.

METHODS

Data from recent national health surveys on black/white differences in major CVD risk factors like hypertension, obesity, cholesterol, cigarette smoking, and physical inactivity were reviewed for the purpose of identifying promising avenues for primordial prevention research among African-Americans.

RESULTS

Cigarette smoking has a delayed onset among African-Americans compared to whites. Black/white differences in "vigorous" leisure-time physical activity (e.g., social dancing and team sports) are not apparent until around age 40. These findings have relevance for primordial prevention work in black communities since they suggest the existence of broad-based, health-relevant cultural norms which could support primordial prevention programs, such as regular physical activity, across the life cycle.

CONCLUSIONS

CVD primordial prevention programs among African-Americans must be grounded in an understanding of how cultural values as well as economic conditions shape CVD risk factor distributions in this population. Ultimate success will depend on the strength of the partnerships that public health researchers, primary care providers, and community residents are able to build.

Initiation of cigarette smoking and subsequent smoking behavior among U.S. high school students

BACKGROUND

Most adult smokers report trying their first cigarette before age 18 years. Understanding the impact of smoking initiation at young ages may help public health policy makers and practitioners improve strategies to prevent or delay adolescent cigarette smoking.

METHODS

This paper examined age of initiation of cigarette smoking and subsequent patterns of smoking among U.S. high school students 16 years of age and older (N = 13,858). We used data from the 1991-1997 national Youth Risk Behavior Surveys, conducted by the Centers for Disease Control and Prevention.

RESULTS

The majority of students 16 years of age and older (60.4%) reported ever having smoked a whole cigarette, and 11.1% initiated smoking at age 10 years or younger. Age of smoking initiation was significantly related to current frequent smoking, daily smoking, and whether students had ever smoked daily. A younger age of smoking initiation was associated with smoking more cigarettes per day than was initiating at an older age.

CONCLUSIONS

Delaying the onset of smoking may affect the likelihood of becoming addicted to nicotine and smoking heavily. For students who are already addicted to nicotine, smoking cessation programs are needed.