Differential contribution of parents and friends to smoking trajectories during adolescence

Tobacco use among in-school young adolescents in Indonesia: Exploring availability, affordability, and accessibility

The research on Indonesian adolescents' perception of tobacco control in schools is limited. This study aimed to explore the availability, affordability, and accessibility of tobacco among young adolescents in Yogyakarta Municipality, Indonesia, with a focus on advocating for school teenagers. Focus groups, comprising participants from diverse backgrounds and stakeholders, were conducted in Yogyakarta, Indonesia, to systematically collect varied data. The subsequent analysis employed a robust thematic approach, combining both inductive and deductive processes to ensure a nuanced exploration of emerging patterns and pre-existing frameworks. In addition to focus group data, the study incorporated insights from extensive field observations and research group discussions. The multifaceted approach enhanced the depth of analysis but also facilitated a comprehensive understanding of the complex dynamics. The findings of this study revealed that young adolescents found it extremely easy to purchase cigarettes from local markets. The smoking prevalence among young adolescents was relatively low, with only 10% of the respondents admitting to smoking. Although the Indonesian government has increased surveillance and regulations regarding smoking among young individuals, the actual implementation and effectiveness of these measures remain questionable. The existing anti-smoking approaches in Indonesia have been unsuccessful in curbing smoking among Indonesian school students. The study argues that it is crucial to recognize and value students' perceptions of smoking, as their knowledge of smoking is actively constructed. To address this issue, future anti-smoking education in schools should incorporate interactive sessions rather than solely relying on didactic approaches that highlight the harms of smoking. By engaging students in interactive discussions, they can actively participate in constructing their understanding of the consequences of smoking. Additionally, efforts should be made to enhance the implementation of tobacco control measures within schools and extend the reach of these measures to off-campus environments.

Analyzing Trajectories of Acute Cigarette Reduction Post-Introduction of an E-Cigarette Using Ecological Momentary Assessment Data

Electronic cigarettes (ECs) may hold great potential for helping smokers transition off combustible cigarettes (CCs); however, little is known about the patterns that smokers follow when using an EC as a CC-substitute in order to ultimately reduce and quit smoking. Our primary aim in this study was to evaluate whether common patterns of CC use exist amongst individuals asked to substitute an EC for at least half of the CCs they would normally smoke. These patterns may elucidate the immediate switching and reduction behaviors of individuals using ECs as a reduction/cessation tool. This analysis uses data from a randomized controlled trial of 84 adult smokers assigned to receive either 4.5% nicotine or placebo (0% nicotine) EC. Participants were advised to use the EC to help them reach a 50% reduction in cigarettes-per-day (CPD) within 3 weeks. Longitudinal trajectory analysis was used to identify CPD reduction classes amongst the sample; participants clustered into four distinct, linear trajectories based on daily CC use during the 3-week intervention. Higher readiness to quit smoking, prior successful quit attempts, and lower baseline CC consumption were associated with assignment into "more successful" CC reduction classes. ECs may be a useful mechanism to promote CC reduction. This study demonstrates that a fine-grained trajectory approach can be applied to examine switching patterns in the critical first weeks of an attempt.

Do high school friends still matter for health behavior in adulthood? Variations in smoking trajectories by adolescent peer smoking networks, race/ethnicity, and gender

Peers play an influential role in the initiation of smoking during adolescence. However, there has been limited literature examining whether adolescent peers are associated with longer-term patterns of smoking. This study uses data from the National Longitudinal Study of Adolescent to Adult Health to examine whether age-based trajectories of smoking likelihood from adolescence to adulthood are associated with the number of adolescent friends who smoked and how this association differs by race/ethnicity and gender. Findings using multilevel growth curve models indicate that individuals who have more adolescent friends who smoked have higher probabilities of smoking during adolescence than those with no adolescent smoking friends. As individuals age into adulthood, the association between adolescent friends’ smoking behavior and individual-level smoking begin to dissipate but does not completely disappear. Further analyses show that there are no differences in this association by gender, but there are differences by race/ethnicity. These findings suggest that high school friends continue to be associated with trajectories of smoking even twenty years after high school. These results indicate that anti-smoking campaigns should take a network approach to preventing smoking in adolescence as well as recognize that the same campaign strategy may not work for all groups.

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Adolescent friends are associated with smoking trajectories into adulthood.

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The friends-smoking association wanes with age but does not completely dissipate.

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This friends-smoking association increases with age for Black adults.

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There are no significant differences in the friends-smoking association by gender.

Cigarette smoking trajectories in adolescent smokers: Does the time axis metric matter?

INTRODUCTION

Most studies modeling adolescent cigarette smoking trajectories use age as the time axis, possibly obscuring depiction of the natural course of cigarette smoking. We used a simulated example and real data to contrast smoking trajectories obtained from models that used time since smoking onset or calendar time (age) as the time axis.

METHODS

Data were drawn from a longitudinal investigation of 1293 grade 7 students (mean age 12.8 years) recruited from 10 high schools in Montreal, Canada in 1999-2000, who were followed into young adulthood. Cigarette consumption was measured every 3 months during high school, and again at mean age 20.4 and 24.0. Analyses using time since onset of smoking as the time metric was restricted to 307 incident smokers; analysis using calendar time included 645 prevalent and incident smokers. Smoking status and nicotine dependence (ND) were assessed at mean age 20.4 and 24.0. Simulated data mimicked the real study during high school.

RESULTS

Use of different time metrics resulted in different numbers and shapes of trajectories in the simulated and real datasets. Participants in the calendar time analyses reported more ND in young adulthood, reflecting inclusion of 388 prevalent smokers who had smoked for longer durations.

CONCLUSIONS

Choosing the right time metric for trajectory analysis should be balanced against research intent. Trajectory analyses using the time since onset metric depict the natural course of smoking in incident smokers. Those using calendar time offer a snapshot of smoking across age during a given time period.

IMPLICATIONS

This study uses simulated and real data to show that trajectory analyses of cigarette smoking that use calendar time (e.g., age) versus time since onset as the time axis metric tell a different story. Trajectory analyses using the time since onset metric depict the natural course of smoking in incident smokers. Those using calendar time offer a snapshot of smoking across age during a given time period. Choosing the right time metric should be balanced against research intent.

Parents, Peers, and Trajectories of Cigarette Smoking: A Group-Based Approach

This study examines the independent, relative, and additive associations between both parent and peer role models and longitudinal patterns of smoking across adolescence and early adulthood. An analysis of data from the National Longitudinal Study of Adolescent to Adult Health (N=10,166) reveals at least four distinct trajectories of smoking across ages 13-35: (1) non-smokers; (2) late peak (almost 10 cigarettes per day around age 30); (3) an early peak group that reached roughly 10 cigarettes per day around age 20 and declined; and (4) a high group that increased during adolescence and early adulthood and then remained high. Parent and peer smoking behaviors were associated with trajectory group membership net of controls for sociodemographic characteristics, parental SES, parent-child relations, and the availability of cigarettes in the family home. Parents and peers appear to have at least some independent associations net of each other, but their combined effects are powerful.

A systematic review of cigarette smoking trajectories in adolescents

Trajectory analyses differentiate subgroups of smokers based on early patterns of cigarette use, but no study has summarized this literature. We systematically reviewed the literature on adolescent cigarette smoking trajectories to document the number and shapes of trajectories identified, assess if certain study characteristics influence the number or shapes of trajectories identified, summarize factors associated with and outcomes of trajectory group membership, and assess whether the results of trajectory analyses help identify windows of opportunity for intervention. We searched PubMed and EMBASE (1/1/1980 to 1/11/2018) and identified 1695 articles. Forty-three articles with data from 37 unique datasets were retained. Each trajectory was categorized into one of three groups (i.e., low-stable, increasing, other). Number of trajectories ranged from 2 to 6 (mode = 4); 44-76% of participants were low-stable cigarette consumers, 11-21% increased consumption, and 3-11% were categorized as "other." Number of data points, smoking indicator used, and time axis influenced the number of trajectories identified. Only two articles depicted the natural course of smoking since onset. Factors associated with trajectory membership included age, sex/gender, race/ethnicity, parental education, behavior problems, depression, academic performance, baseline cigarette use, parental and friends smoking, alcohol use, and cannabis use. Outcomes included illicit drug and alcohol use. Beyond parsimoniously describing cigarette smoking patterns, it is not clear whether trajectory analyses offer increased insight into the natural course, determinants or outcomes of cigarette smoking in ways that inform the development of intervention.

Cross-Cultural Comparison of Genetic and Cultural Transmission of Smoking Initiation Using an Extended Twin Kinship Model

BACKGROUND

Considerable evidence from twin and adoption studies indicates that genetic and shared environmental factors play a role in the initiation of smoking behavior. Although twin and adoption designs are powerful to detect genetic and environmental influences, they do not provide information on the processes of assortative mating and parent-offspring transmission and their contribution to the variability explained by genetic and/or environmental factors.

METHODS

We examined the role of genetic and environmental factors in individual differences for smoking initiation (SI) using an extended kinship design. This design allows the simultaneous testing of additive and non-additive genetic, shared and individual-specific environmental factors, as well as sex differences in the expression of genes and environment in the presence of assortative mating and combined genetic and cultural transmission, while also estimating the regression of the prevalence of SI on age. A dichotomous lifetime 'ever' smoking measure was obtained from twins and relatives in the 'Virginia 30,000' sample and the 'Australian 25,000'.

RESULTS

Results demonstrate that both genetic and environmental factors play a significant role in the liability to SI. Major influences on individual differences appeared to be additive genetic and unique environmental effects, with smaller contributions from assortative mating, shared sibling environment, twin environment, cultural transmission, and resulting genotype-environment covariance. Age regression of the prevalence of SI was significant. The finding of negative cultural transmission without dominance led us to investigate more closely two possible mechanisms for the lower parent-offspring correlations compared to the sibling and DZ twin correlations in subsets of the data: (1) age × gene interaction, and (2) social homogamy. Neither of the mechanism provided a significantly better explanation of the data.

CONCLUSIONS

This study showed significant heritability, partly due to assortment, and significant effects of primarily non-parental shared environment on liability to SI.

The influence of peer behavior as a function of social and cultural closeness: A meta-analysis of normative influence on adolescent smoking initiation and continuation

Although the influence of peers on adolescent smoking should vary depending on social dynamics, there is a lack of understanding of which elements are most crucial and how this dynamic unfolds for smoking initiation and continuation across areas of the world. The present meta-analysis included 75 studies yielding 237 effect sizes that examined associations between peers' smoking and adolescents' smoking initiation and continuation with longitudinal designs across 16 countries. Mixed-effects models with robust variance estimates were used to calculate weighted-mean Odds ratios. This work showed that having peers who smoke is associated with about twice the odds of adolescents beginning (OR ¯ = 1.96, 95% confidence interval [CI] [1.76, 2.19]) and continuing to smoke (OR ¯ = 1.78, 95% CI [1.55, 2.05]). Moderator analyses revealed that (a) smoking initiation was more positively correlated with peers' smoking when the interpersonal closeness between adolescents and their peers was higher (vs. lower); and (b) both smoking initiation and continuation were more positively correlated with peers' smoking when samples were from collectivistic (vs. individualistic) cultures. Thus, both individual as well as population level dynamics play a critical role in the strength of peer influence. Accounting for cultural variables may be especially important given effects on both initiation and continuation. Implications for theory, research, and antismoking intervention strategies are discussed. (PsycINFO Database Record

New Zealand adolescents' discouragement of smoking among their peers

OBJECTIVE

This study examines the extent to which young people are acting as 'agents of change' in discouraging smoking among their peers.

METHODS

This study used data from a survey of 2,919 New Zealand secondary school students who participated in the 2014 national Youth In-depth Survey. Relevant questions were used to assess the extent to which students engaged in behaviours to discourage or promote smoking among their peers.

RESULTS

About half of all students reported some form of behaviour discouraging others from smoking, while only one in ten reported encouraging smoking. Discouragement was associated with non-smoking or lower levels of smoking, having more friends who smoked, and exposure to more health promotion messages about not smoking. Māori and Pacific young people also reported more discouraging behaviours.

CONCLUSIONS

The results highlight the positive impact that young people can have on discouraging smoking among their peers. Implications for public health: The findings of this study point to encouraging and training young people as 'agents of change' to spread the smokefree message.

Psychometric evaluation of an abbreviated version of the intragroup marginalization inventory

Tobacco and marijuana use among U.S. young adults is a top public health concern, and racial/ethnic minorities may be at particular risk. Past research examining cultural variables has focused on the individual in relation to the mainstream U.S. culture; however, an individual can also experience within-group stress, or intragroup marginalization. We used the 2014 San Francisco Bay Area Young Adult Health Survey to validate an abbreviated measure of intragroup marginalization and identify associations between intragroup marginalization and tobacco and marijuana use among ethnic minority young adults (N = 1,058). Exploratory factor analysis was conducted to identify factors within the abbreviated scale, and logistic regressions were conducted to examine relationships between intragroup marginalization and tobacco and marijuana use. Two factors emerged from the abbreviated scale. The first factor encompassed items related to belonging and membership, capturing whether individuals experienced marginalization due to not fitting in because of physical appearance or behavior. The second factor encompassed whether individuals shared similar hopes and dreams to their friends and family members. Factor 1 (membership) was associated with increased odds of marijuana use (OR = 1.34, p < .05) and lower odds of using cigars (OR = 0.79, p < .05), controlling for sociodemographic factors. Results suggest that young adults may use marijuana as a means to build connection and belonging to cope with feeling marginalized. Health education programs focused on ethnic minority young adults are needed to help them effectively cope with intragroup marginalization without resorting to marijuana use.

Can smoking initiation contexts predict how adult Aboriginal smokers assess their smoking risks? A cross-sectional study using the 'Smoking Risk Assessment Target'

OBJECTIVES

Smoking prevalence is slow to reduce among Indigenous Australians of reproductive age. We analysed the relationships between age of smoking initiation, recalled initiation influences and self-assessment of smoking risks in Aboriginal smokers.

DESIGN, SETTING AND PARTICIPANTS

A community-based cross-sectional survey of Aboriginal smokers aged 18-45 years (N=121; 58 men) was undertaken, using single-item measures. The Smoking Risk Assessment Target (SRAT) as the primary outcome measure enabled self-assessment of smoking risks from 12 options, recategorised into 3 groups. Participants recalled influences on their smoking initiation. Multinomial logistic regression modelling included age, gender, strength of urges to smoke, age at initiation (regular uptake) and statistically significant initiation influences on χ(2) tests ('to be cool', alcohol and cannabis).

RESULTS

Frequent initiation influences included friends (74%; SD 0.44), family (57%; SD 0.5) and alcohol (40%; SD 0.49). 54% (n=65) of smokers had the highest risk perception on the SRAT, selected by those who cared about the smoking risks and intended to quit soon. On multivariate analyses, compared with the highest level of SRAT, male gender, lower age of uptake and strong urges to smoke were significantly associated with the lowest level of SRAT, selected by those who refuted risks or thought they could not quit. Lower age of uptake and alcohol were associated with mid-level of SRAT, selected by those who cared about smoking risks, but did not consider quitting as a priority.

CONCLUSIONS

Characteristics of smoking initiation in youth may have far-reaching associations with how smoking risks are assessed by adults of reproductive age, and their intentions to quit smoking. Becoming a regular smoker at under the age of 16 years, and influences of alcohol on smoking uptake, were inversely associated with high-level assessment of smoking risks and intention to quit in regional Aboriginal smokers. The SRAT may help tailor approaches to Indigenous smoking cessation.

Influence of family and friend smoking on intentions to smoke and smoking-related attitudes and refusal self-efficacy among 9-10 year old children from deprived neighbourhoods: a cross-sectional study

Background

Smoking often starts in early adolescence and addiction can occur rapidly. For effective smoking prevention there is a need to identify at risk groups of preadolescent children and whether gender-specific intervention components are necessary. This study aimed to examine associations between mother, father, sibling and friend smoking and cognitive vulnerability to smoking among preadolescent children living in deprived neighbourhoods.

Methods

Cross-sectional data was collected from 9–10 year old children (n =1143; 50.7% girls; 85.6% White British) from 43 primary schools in Merseyside, England. Children completed a questionnaire that assessed their smoking-related behaviour, intentions, attitudes, and refusal self-efficacy, as well as parent, sibling and friend smoking. Data for boys and girls were analysed separately using multilevel linear and logistic regression models, adjusting for individual cognitions and school and deprivation level.

Results

Compared to girls, boys had lower non-smoking intentions (P = 0.02), refusal self-efficacy (P = 0.04) and were less likely to agree that smoking is ‘definitely’ bad for health (P < 0.01). Friend smoking was negatively associated with non-smoking intentions in girls (P < 0.01) and boys (P < 0.01), and with refusal self-efficacy in girls (P < 0.01). Sibling smoking was negatively associated with non-smoking intentions in girls (P < 0.01) but a positive association was found in boys (P = 0.02). Boys who had a smoking friend were less likely to ‘definitely’ believe that the smoke from other people’s cigarettes is harmful (OR 0.57, 95% CI: 0.35 to 0.91, P = 0.02). Further, boys with a smoking friend (OR 0.38, 95% CI: 0.21 to 0.69, P < 0.01) or a smoking sibling (OR 0.45, 95% CI: 0.21 to 0.98) were less likely to ‘definitely’ believe that smoking is bad for health.

Conclusion

This study indicates that sibling and friend smoking may represent important influences on 9–10 year old children’s cognitive vulnerability toward smoking. Whilst some differential findings by gender were observed, these may not be sufficient to warrant separate prevention interventions. However, further research is needed.

Initial responses to the first dose of nicotine in novel smokers: the role of exposure to environmental smoking and genetic predisposition

BACKGROUND

Sensitivity to initial smoking constitutes an early predictor of the risk of dependence. We investigated the role of exposure to smoking (by parents, siblings, and peers) and reward-related candidate gene polymorphisms (OPRM1 A118G, DRD2 TaqlA and DRD4 bp VNTR) in adolescents' responses to initial smoking.

METHODS

We used cross-sectional survey data and saliva samples from 171 Dutch students who had never inhaled on a cigarette (mean age: 13.9 years). The outcome measure was adolescents' self-reported responses to initial smoking.

RESULTS

Exposure to peer smoking was associated with increased liking (OR = 1.74, CI = 1.13-2.70) and more pleasant sensations (β = .21, p = .01). Exposure to maternal smoking was associated with less unpleasant sensations (β = -.20, p = .01). Adolescents carrying the G-variant of the OPRM1 A118G polymorphism were more likely to report liking (OR = 2.50, CI = 1.09-5.73) and adolescents homozygous for the C-variant of the DRD2 TaqlA polymorphism reported less unpleasant sensations (β = .18, p = .04).

CONCLUSION

Although preliminary, these findings suggest that exposure to environmental smoking and polymorphisms in the OPRM1 and DRD2 gene may affect initial sensitivity to nicotine, an early phenotype of the risk of dependence. In the future, collaborative efforts to combine data from multiple studies in meta-analyses are needed to improve accuracy of estimated effects in genetic studies.

Environmental smoking and smoking onset in adolescence: the role of dopamine-related genes. Findings from two longitudinal studies

Although environmental smoking (i.e., paternal and maternal smoking, sibling smoking, and peer smoking) is one of the most important factors for explaining adolescent smoking behavior, not all adolescents are similarly affected. The extent to which individuals are vulnerable to smoking in their environment might depend on genetic factors. The aim of this study was to examine the interplay between environmental smoking and genes encoding components of the dopaminergic system (i.e., dopamine receptor D2, D4, and dopamine transporter DAT1) in adolescent smoking onset. Data from two longitudinal studies were used. Study 1 consisted of 991 non-smoking early adolescents (mean age = 12.52, SD = .57) whereas study 2 consisted of 365 non-smoking middle to late adolescents (mean age = 14.16, SD = 1.07) who were followed for 16 and 48 months, respectively. Logistic regression analyses were conducted using Mplus. In study 1, we found positive associations between parents' and friends' smoking at the first measurement and smoking status 16 months later. In study 2 we found a positive association between friends' smoking and smoking onset 48 months later. Neither study demonstrated any interaction effects of the DRD2, DRD4, or DAT1 genotypes. In conclusion, the effects of environmental smoking on smoking onset are similar for adolescent carriers and non-carriers of these specific genes related to the dopaminergic system.

Individual- and community-level correlates of cigarette-smoking trajectories from age 13 to 32 in a U.S. population-based sample

BACKGROUND

Characterizing smoking behavior is important for informing etiologic models and targeting prevention efforts. This study explored the effects of both individual- and community-level variables in predicting cigarette use vs. non-use and level of use among adolescents as they transition into adulthood.

METHODS

Data on 14,779 youths (53% female) were drawn from the National Longitudinal Study of Adolescent Health (Add Health); a nationally representative longitudinal cohort. A cohort sequential design allowed for examining trajectories of smoking typologies from age 13 to 32 years. Smoking trajectories were evaluated by using a zero-inflated Poisson (ZIP) latent growth analysis and latent class growth analysis modeling approach.

RESULTS

Significant relationships emerged between both individual- and community-level variables and smoking outcomes. Maternal and peer smoking predicted increases in smoking over development and were associated with a greater likelihood of belonging to any of the four identified smoking groups versus Non-Users. Conduct problems and depressive symptoms during adolescence were related to cigarette use versus non-use. State-level prevalence of adolescent smoking was related to greater cigarette use during adolescence.

CONCLUSIONS

Individual- and community-level variables that distinguish smoking patterns within the population aid in understanding cigarette use versus non-use and the quantity of cigarette use into adulthood. Our findings suggest that efforts to prevent cigarette use would benefit from attention to both parental and peer smoking and individual well-being. Future work is needed to better understand the role of variables in the context of multiple levels (individual and community-level) on smoking trajectories.

HIV-infected adolescent, young adult and pregnant smokers: important targets for effective tobacco control programs

Tobacco use is inextricably linked to a number of health risks both in the general and HIV-infected populations. There is, however, a dearth of research on effective tobacco control programs among people living with HIV, and especially among adolescents, young adults and pregnant women, groups with heightened or increased vulnerability secondary to tobacco use. Adolescents and young adults constitute a growing population of persons living with HIV infection. Early and continued tobacco use in this population living with a disease characterized by premature onset multimorbidity and chronic inflammation is of concern. Additionally, there is an increased acuity for tobacco control among HIV-infected pregnant women to reduce pregnancy morbidity and improve fetal outcome. This review will provide an important summary of current knowledge of tobacco use among HIV-infected adolescents, young adults and pregnant women. The effects of tobacco use in these specific populations will be presented and the current state of tobacco control within these populations, assessed.

Predictors of nicotine dependence symptoms among never-smoking adolescents: a longitudinal analysis from the Nicotine Dependence in Teens Study

BACKGROUND

Recent cross-sectional studies suggest some adolescents who have never smoked cigarettes experience nicotine dependence (ND) symptoms and that exposure to second-hand smoke, social exposure to smoking, and alcohol use are plausible correlates. The aim of this study was to replicate and extend these findings by investigating possible predictors of ND symptoms longitudinally.

METHOD

Participants included 847 secondary school students who had never smoked cigarettes enrolled in the Nicotine Dependence in Teens Study. Adolescents completed self-report questionnaires measuring smoking status, ND symptoms, and risk factors for ND in smokers (i.e., socio-demographic indicators, social exposure to smoking, psychosocial indicators, and substance use) in 20 survey cycles from 7 to 11th grade. Generalized estimating equations, which account for repeated measures within individuals, were used to test the predictors of ND symptoms.

RESULTS

Consistent with previous research, 7.8% of never-smokers across all cycles endorsed at least one ND symptom. Younger age (p ≤ .001), country of birth (p ≤ .05), peer smoking (p ≤ .001), teacher smoking (p ≤ .05), depression (p ≤ .05), stress (p ≤ .001), lower self-esteem (p ≤ .05), impulsivity (p ≤ .05), and alcohol use (p ≤ .001) predicted greater ND symptoms in multivariable modeling.

CONCLUSIONS

Replicating previous cross-sectional findings, peer smoking and alcohol use predicted ND symptoms among never-smoking adolescents. Extending these findings, previous predictors only observed among ever-smokers, including socio-demographic and psychosocial indicators, also predicted ND symptoms. This longitudinal investigation demonstrated the temporal relation of the predictors preceding ND symptoms. Future research should consider longer prospective studies with younger children to capture early onset of ND symptoms and with longer follow-up to detect eventual smoking uptake.

The role of environmental smoking in smoking-related cognitions and susceptibility to smoking in never-smoking 9-12 year-old children

Environmental smoking has numerous adverse effects on child health, and children are frequently exposed to environmental smoking. In the present study, we investigated the role of environmental smoking (parental smoking, sibling smoking, peer smoking) in smoking-related cognitions (pros of smoking, perceived safety of casual smoking, cue-triggered wanting to smoke) and susceptibility to smoking among 9-12 year old never-smoking children (N=778). We collected cross-sectional survey data from children attending 15 Dutch primary schools. Using structural equation modelling, we assessed direct as well as indirect relationships among study variables. The results showed that children who were exposed to more smoking parents, siblings, and peers perceived more pros of smoking. Additionally, parental smoking was associated with higher perceived safety of casual smoking and more cue-triggered wanting to smoke. In turn, perceiving a higher safety of casual smoking and more cue-triggered wanting to smoke were associated with a higher susceptibility to smoking in children. No direct effects of environmental smoking on children's susceptibility to smoking were found. However, parental smoking was associated with children's susceptibility to smoking through children's perceived safety of casual smoking and cue-triggered wanting to smoke. The present study indicates that pre-adolescents may already display favourable smoking-related cognitions and that these cognitions may be an early indicator of a child's vulnerability to smoking. Environmental smoking, particularly parental smoking, is associated with more favourable smoking-related cognitions in never-smoking children. In the intergenerational transmission of smoking from parents to children, children's risk perceptions of smoking and the experience of cue-triggered wanting to smoke may constitute mechanisms of action, which need to be investigated in longitudinal research.

Starting to smoke: a qualitative study of the experiences of Australian indigenous youth

Background

Adult smoking has its roots in adolescence. If individuals do not initiate smoking during this period it is unlikely they ever will. In high income countries, smoking rates among Indigenous youth are disproportionately high. However, despite a wealth of literature in other populations, there is less evidence on the determinants of smoking initiation among Indigenous youth. The aim of this study was to explore the determinants of smoking among Australian Indigenous young people with a particular emphasis on the social and cultural processes that underlie tobacco use patterns among this group.

Methods

This project was undertaken in northern Australia. We undertook group interviews with 65 participants and individual in-depth interviews with 11 youth aged 13–20 years led by trained youth ‘peer researchers.’ We also used visual methods (photo-elicitation) with individual interviewees to investigate the social context in which young people do or do not smoke. Included in the sample were a smaller number of non-Indigenous youth to explore any significant differences between ethnic groups in determinants of early smoking experiences. The theory of triadic influence, an ecological model of health behaviour, was used as an organising theory for analysis.

Results

Family and peer influences play a central role in smoking uptake among Indigenous youth. Social influences to smoke are similar between Indigenous and non-Indigenous youth but are more pervasive (especially in the family domain) among Indigenous youth. While Indigenous youth report high levels of exposure to smoking role models and smoking socialisation practices among their family and social networks, this study provides some indication of a progressive denormalisation of smoking among some Indigenous youth.

Conclusions

Future initiatives aimed at preventing smoking uptake in this population need to focus on changing social normative beliefs around smoking, both at a population level and within young peoples’ immediate social environment. Such interventions could be effectively delivered in both the school and family environments. Specifically, health practitioners in contact with Indigenous families should be promoting smoke free homes and other anti-smoking socialisation behaviours.

Genetic influences on developmental smoking trajectories

AIMS

To investigate the relative contribution of genetic and environmental factors on smoking trajectory membership and to test whether individual smoking trajectories represent phenotypical thresholds of increasing genetic risk along a common genetic liability dimension.

DESIGN

Prospective study of a birth cohort of female like-sex twin pairs.

SETTING

Participants completed diagnostic interview surveys four times from adolescence (average age 16) to young adulthood (average age 25).

PARTICIPANTS

Female twins who had smoked ≥100 cigarettes life-time (n = 1466 regular smokers).

MEASUREMENTS

Number of cigarettes smoked per day during the heaviest period of smoking (two waves) or during the past 12 months (two waves).

FINDINGS

A four-trajectory class solution provided the best fit to cigarette consumption data and was characterized by low (n = 564, 38.47%), moderate (n = 366, 24.97%) and high-level smokers (n = 197, 13.44%), and smokers who increased their smoking from adolescence to young adulthood (n =339, 23.12%). The best genetic model fit was a three-category model that comprised the low, a combined increasing + moderate and high trajectories. This trajectory categorization was heritable (72.7%), with no evidence for significant contribution from shared environmental factors.

CONCLUSIONS

The way in which smoking patterns develop in adolescence has a high level of heritability.

Smoking-specific communication and children's smoking onset: an extension of the theory of planned behaviour

The aim of this study was to test whether maternal smoking-specific communication and parental smoking related to smoking cognitions (i.e. attitude, self-efficacy and social norm) derived from the Theory of Planned Behaviour in association with smoking onset during preadolescence. A total of 1478 pairs of mothers and children participated (mean age: 10.11; standard deviation = 0.78). Structural equation models in Mplus were used to examine whether smoking-specific communication influences children's smoking cognitions, which in turn, affect smoking onset. A positive association was found between pro-smoking attitudes and smoking onset. Smoking-specific communication and parental smoking were related to smoking cognitions. Specifically, frequency of communication was negatively associated with pro-smoking attitudes, social norms of mother and best friend. Quality of communication related negatively to pro-smoking attitudes and positively to self-efficacy and norms of friends. Parental smoking was positively associated with pro-smoking attitudes and norms of mother and (best) friends. Additionally, more frequent communication and higher levels of parental smoking were associated with higher smoking onset. In conclusion, smoking-specific communication and parental smoking were associated with smoking cognitions and smoking onset. Already during preadolescence, parents contribute to shaping the smoking cognitions of their children, which may be predictive of smoking later in life.

Smoking of parents and best friend--independent and combined effects on adolescent smoking and intention to initiate and quit smoking

INTRODUCTION

This study investigates the independent and combined effects of smoking of parents and best friend on smoking and the intention to initiate or quit smoking in adolescents.

METHODS

In this school-based survey, 6,553 Hong Kong students aged 13-18 reported their demographic characteristics, smoking status of themselves, parents, and best friend; and intention to smoke (initiation among never-smokers and reinitiation among ex-smokers) or quit smoking among current smokers. Logistic regression yielded adjusted odds ratios (AORs) of student smoking (current/ever) and intention to smoke or quit smoking for parental (paternal/maternal/both parents vs. none) and best friend (yes vs. no) smoking.

RESULTS

Parental smoking and having a smoking best friend were associated with adolescent current smoking, ever smoking, and intention to initiate smoking. Having a smoking best friend was also associated with reinitiating and quitting smoking. The AORs (95% CI) of current smoking for having a smoking best friend, in addition to smoking father, mother, or both were 19.14 (14.36-25.51), 20.38 (12.42-33.43), and 24.18 (15.89-36.77). The respective AORs of ever smoking were 8.30 (6.74-10.22), 8.92 (5.63-14.12), and 11.99 (8.05-17.87).

CONCLUSIONS

Parental smoking and best friend smoking have independent effects on adolescent smoking behaviors. Their combined effects on current and ever smoking were particularly large. Smoking prevention programs should pay special attention to adolescents with both best friend and parents who smoke.

The influence of parents, siblings and peers on pre- and early-teen smoking: a multilevel model

INTRODUCTION AND AIMS

Despite considerable success in tobacco control, many teenagers in Australia and other industrialised countries still smoke tobacco. There is mixed evidence on the relative influence of proximal social networks (parents/siblings/peers) on pre- and early-teen smoking, and no research has examined how these influences compare after accounting for school- and community-level effects.The aim of this study was to compare the relative influences of parents, siblings and peers, after accounting for school- and community-level variation in smoking.

DESIGN AND METHODS

A cross-sectional fixed and random effects model of smoking prevalence was used, with individuals (n = 7314) nested within schools (n = 231) nested within communities (n = 30). Grade 6 and 8 students (modal ages 11 and 13 years) completed an on-line survey. Key variables included parent/sibling/peer use. Controls included alcohol involvement, sensation seeking, pro-social beliefs, laws/norms about substance use and school commitment.

RESULTS

There was significant variation in smoking at both the school and community levels, supporting the need for a multilevel model. Individual-level predictors accounted for much of the variance at higher levels. The strongest effects were for number of friends who smoke, sibling smoking and alcohol involvement. Smaller significant effects were found for parent smoking. At the community level, socioeconomic disadvantage was significant, but community-level variance in pro-social and drug-related laws/norms was not related to smoking.

DISCUSSION AND CONCLUSIONS

Cross-level interactions were generally non-significant. Early teenage smoking was best explained by sibling and peer smoking, and individual risks largely accounted for the substantial variation observed across schools and communities. In terms of future tobacco control, findings point to the utility of targeting families in disadvantaged communities.

The changing role of self-efficacy in adolescent smoking initiation

BACKGROUND

Refusal self-efficacy is assumed to be linked to adolescent smoking. The aim of the present study was to examine the changing role of self-efficacy in adolescent smoking over time while controlling for parental, sibling, and friends' smoking.

METHODS

This study used data from five annual waves of the "Family and Health" project. A total of 428 adolescents (mean age = 13.3 years; standard deviation = .48) and their parents participated at baseline. Only never smokers at baseline (n = 272) were included to measure smoking initiation. First, the effects of baseline self-efficacy, parental, sibling, and friends' smoking on adolescent smoking initiation at measurement five were examined. Second, with latent growth curves analyses, individual growth curve parameters of adolescent smoking, self-efficacy, parental, sibling, and friends' smoking were calculated. Subsequently, these growth parameters were used to predict growth of adolescent smoking.

RESULTS

Findings showed that baseline self-efficacy, parental and friends' smoking did not predict adolescent smoking at wave five, but baseline sibling smoking did. However, growth curve parameters showed that a decrease in self-efficacy, an increase in proportion of smoking friends, and an increase in sibling smoking over time were related to an increase in adolescent smoking. Initial levels of sibling and friends' smoking moderated the link between self-efficacy and adolescent smoking over time.

CONCLUSION

A decrease in self-efficacy over time, rather than baseline self-efficacy, is associated with smoking initiation in adolescence. Findings emphasize the need for more fine-grained analyses when looking at self-efficacy or other individual characteristics that might fluctuate over time.

The relation between smoking-specific parenting and smoking trajectories of adolescents: how are changes in parenting related to changes in smoking?

In this study, we tested to what extent smoking-specific parenting and changes in parenting are related to adolescents' smoking trajectories. Data were used from a four-wave prospective study including 428 adolescents (aged M = 15.2; SD = 0.60). Latent Class Growth Analyses were conducted to identify trajectories. Multinomial Logistic Regression Analyses were executed to examine the relations between parenting and class membership. Longitudinal cross-lagged models were tested to examine causal predominance between parenting and smoking. Four trajectories were found, consisting of Non-smokers, Increasers, Stable smokers and Decreasers. Quality of parental smoking-specific communication was strongly related to the membership in different trajectories. Along with the cross-lagged associations demonstrating that the quality of communication was predominantly related to future smoking rather than vice versa, these findings indicate that parents who talked about smoking in a constructive and respectful manner were more likely to have non-smoking children. In contrast, parents who talked often about smoking-related issues and increased these discussions over time were more likely to have smoking children; cross-lagged associations indicated that these findings could be best explained by children changing their parents. Having a non-smoking agreement was related to a lower risk in becoming a regular smoker.

Social influence, intention to smoke, and adolescent smoking behaviour longitudinal relations

OBJECTIVES

There is a debate on the determinants of smoking behaviour, their relative impact, and how impacts are exerted. This longitudinal study is on the relations among social influence, intention to smoke, and smoking behaviour, controlling for attitude and self-efficacy.

DESIGN AND METHODS

A model combining parents and peers with subjective and descriptive norms, resulting in four factors, was used to assess social influence. Data were collected at the beginning of the 7th(-T1), 8th(-T2), and 9th(-T3) school years, concerning 578 students (M(age) = 13.04 at T1). Structural Equation Modelling was used to test longitudinal effects.

RESULTS

Variances explained by the model were high: R(2) (intention-T2) = .65, R(2) (behaviour-T2) = .67, and R(2) (behaviour-T3) = .76. Longitudinal analyses confirmed the effects of social influence on intention and behaviour. These effects on behaviour were direct and indirect (peers' and parents' descriptive norms in both cases). Descriptive norms had a stronger effect on behaviour than subjective norms. Peers' effect on behaviour was stronger than parents', but peers' effect was exerted only through descriptive norms while parents' effect was exerted through both norms. The intention effect on behaviour was not as detached as expected and its role of full mediator between other variables' effects on behaviour was not confirmed, since descriptive norms and self-efficacy had also a mediation role.

CONCLUSIONS

Results show direct and indirect effects of social influence on behaviour. Descriptive norms are an important variable to operationalize social influence. Peers and parents exert influence on adolescents' intention and behaviour through different processes. The impact of intention on behaviour is not as important as expected.

Recent findings on peer group influences on adolescent smoking

This review addresses peer group influences on adolescent smoking with a particular focus on recently published longitudinal studies that have investigated the topic. Specifically, we examine the theoretical explanations for how social influence works with respect to adolescent smoking; discuss the association between peer and adolescent smoking; consider socialization and selection processes with respect to smoking; investigate the relative influence of best friends, close friends, and crowd affiliations; and examine parenting behaviors that could buffer the effects of peer influence. Our review indicates the following with respect to adolescent smoking: (a) substantial peer group homogeneity of smoking behavior; (b) support for both socialization and selection effects, although evidence is somewhat stronger for selection; (c) an interactive influence of best friends, peer groups, and crowd affiliation; and (d) an indirect protective effect of positive parenting practices against the uptake of adolescent smoking. We conclude with implications for research and prevention programs.

Critical discussion of social-cognitive factors in smoking initiation among adolescents

Social-cognitive models have often been used in research on prevention in adolescent populations, even though the models were designed to describe adult behavior. The aim of the study reported here was to examine critically and constructively the five social-cognitive factors in the 'attitude, social influence, self-efficacy' (ASE) model. Methods. The examination draws on the results of a qualitative follow-up study of smoking initiation based on semi-structured interviews and observations of 12 adolescents in two Danish school classes, grades 7 and 8. The qualitative study was conducted in connection with and sampled from a large quantitative study and the results of both studies are discussed. In the analyses, we explored the ASE constructs according to how they are described in the ASE theory. Furthermore, we examined contradictions and aspects which are not explained in the model and if relevant discussed these aspects using other theoretical frameworks. Results. The results showed that aspects other than those in the ASE model are also important. Smoking initiation was often situational and unplanned and was sometimes used in negotiating social relationships and identity. Furthermore, the social-cognitive models are based on the assumption that adolescents talk about smoking norms and have a high degree of individual reflexivity, which is not always characteristic of adolescent behavior. Conclusion. Applying theoretical models in health research should be a continuous process of both applying the model and discussing the theoretical assumptions of the model when applied to a specific sample. The results of the qualitative study provide some support for use of the ASE model, but the results also suggest that further studies are needed to explore how social-cognitive models can be expanded to be more comprehensive behavioral models.

Using System Dynamics tools to gain insight into intervention options related to the interaction between tobacco and tuberculosis

Tobacco exposure is an important risk factor for tuberculosis (TB) when considering its effects on population-level disease outcomes. If we hope to gain control over TB globally, we must begin to think ‘outside of the box’ to identify an extended and multi-faceted intervention strategy that is grounded in an understanding of the particular ways in which key risk factors worsen TB. In light of the role of tobacco exposure as an important, identifiable, modifiable, and preventable risk factor for TB, efforts aiming at reducing tobacco use merit inclusion in such a comprehensive TB control program. The goal of this paper is to share the conceptual framework we have developed using System Dynamics methodology, which diagrams the likely effects of tobacco exposure on TB dynamics in a typical low-income country setting. Using this framework as a guide, we leverage an understanding of the likely mechanisms by which tobacco exposure affects TB risk to systematically explore TB control intervention options. We hope that this paper will help inspire new approaches to extend and enhance traditional TB control efforts. We also hope that the conceptual framework will spark further discussion and research on this important and potentially explosive combination of global public health crises.

Evaluation of California's in-school tobacco use prevention education (TUPE) activities using a nested school-longitudinal design, 2003-2004 and 2005-2006

BACKGROUND

Current legislative language requires the California Department of Public Health, California Tobacco Control Program, to evaluate the effectiveness of the school-based Tobacco Use Prevention Education (TUPE) programme in California every 2 years. The objective of the study was to measure change and to identify the impact of school-based tobacco use prevention education activities on youth smoking prevalence and attitudes over time, spanning two school year surveys (2003-2004 and 2005-2006).

METHODS

Evaluation focused on school-based tobacco use prevention activities in 57 schools (student sample size, n=16 833) that participated in the in-school administration of the 2003-2004 and 2005-2006 California Student Tobacco Surveys. Hierarchical linear models were used to predict student tobacco use and precursors to tobacco use.

RESULTS

Overall, student tobacco use, intention to smoke, number of friends smoking and perceived smoking prevalence by peers increased as students moved through grades 9 and 10 to grades 11 and 12. TUPE-related activities showed a suggestive association (p=0.06) with reduced rate in student tobacco use between the two surveys after adjusting for other contextual factors such as each school's socioeconomic characteristics.

CONCLUSIONS

TUPE activities appears to be beneficial in reducing tobacco use in California high school students over time. Other contextual factors were important moderating influences on student tobacco use.

Contribution of parental and school personnel smoking to health risk behaviours among Finnish adolescents

BACKGROUND

This study compared parental smoking with school personnel smoking in relation to adolescents' smoking behaviours, alcohol use, and illicit drug use.

METHODS

A cross-sectional survey for 24,379 adolescents was linked to a survey for 1946 school employees in 136 Finnish schools in 2004-2005. Surveys included smoking prevalence reported by school staff, adolescents' reports of school staff and parental smoking, adolescents' own smoking behaviours, alcohol use, and illicit drug use. Multilevel analyses were adjusted for individual and school-level confounding factors.

RESULTS

Parental smoking was associated with all health risk behaviours among both sexes (risk range 1.39 to 1.95 for other outcomes; Odds Ratio OR for smoking cessation 0.64, 95% Confidence Interval CI: 0.57, 0.72 among boys, 0.72; 0.64, 0.81 among girls). Among boys, high vs. low smoking prevalence among school personnel was associated with higher probability of smoking (OR 1.19; 95% CI 1.01,1.41), higher frequency of smoking during school time (Cumulative Odds Ratio COR 1.81; 95% CI 1.32, 2.48), frequent alcohol use (OR 1.23; 95% CI 1.01, 1.50), illicit drug use (OR 1.40; 95% CI 1.16, 1.69), and higher odds of reporting adults smoking at school (COR 1.51; 95% CI 1.09, 2.09). Among girls, high smoking prevalence among school personnel was related to higher odds of smoking (OR 1.18; 95% CI 1.02, 1.37) and lower odds of smoking cessation (OR 0.84; 95% CI 0.72, 0.99).

CONCLUSION

Parental smoking and school personnel smoking are both associated with adolescents' health risk behaviours but the association of parental smoking seems to be stronger.

Relative risks of exposure to different smoking models on the development of nicotine dependence during adolescence: a five-wave longitudinal study

PURPOSE

Many studies have focused upon predictors of smoking onset and continuation in adolescents. However, less is known about the development of nicotine dependence (ND) and how smoking in the interpersonal environment relates to this. To examine which smoking models have the largest impact on the development of ND, we examined the relative impact of current smoking from fathers, mothers, siblings, best friends, and friend groups on the development of ND in adolescents.

METHODS

Data were used from five annual waves of the "Family and Health" survey project. At baseline 428 adolescents (mean age=15.2 years; SD=.60), both their parents, and their siblings were participating. In this study we included only smoking adolescents (n=175). To assess the individual development of ND of each adolescent, and whether current smoking exposure affected changes from baseline across time, we used latent growth curve modeling (LGC).

RESULTS

Findings revealed that smoking of sibling and best friend were related to baseline levels of ND, but not to the rates of change over time. Of all models, only having smoking friends in the friend group was related to a faster development of ND.

CONCLUSIONS

The current findings highlight the key role of smoking friends in the development of ND and suggest that interventions targeting at peers are probably effective in reducing the prevalence of ND symptoms among adolescents.

Constitutional mechanisms of vulnerability and resilience to nicotine dependence

The core nature of nicotine dependence is evident in wide variations in how individuals become and remain smokers. Individuals with pre-existing behavioral traits are more likely to develop nicotine dependence and experience difficulty when attempting to quit. Many molecular factors likely contribute to individual variations in the development of nicotine dependence and behavioral traits in complex manners. However, the identification of such molecules has been hampered by the phenotypic complexity of nicotine dependence and the complex ways molecules affect elements of nicotine dependence. We hypothesize that nicotine dependence is, in part, a result of interactions between nicotine and pre-existing behavioral traits. This perspective suggests that the identification of the molecular bases of such pre-existing behavioral traits will contribute to the development of effective methods for reducing smoking dependence and for helping smokers to quit.

Disruptiveness, peer experiences and adolescent smoking: a long-term longitudinal approach

AIMS

This study examined links of peer experiences (i.e. social status and affiliation with disruptive peers) throughout childhood with respect to adolescent smoking trajectories, after controlling for childhood disruptiveness. Specifically, we tested four models regarding links of peer experiences and deviant behaviours.

DESIGN

Prospective community sample.

PARTICIPANTS

A total of 312 children, aged 6.17 years at baseline.

MEASUREMENTS

Growth parameters of own disruptive behaviour, disruptive behaviour of friends and social status measured at ages 7-12 years as predictors of smoking assessed at ages 13-15 years, while controlling for own disruptive behaviour at age 6 years.

FINDINGS

We found three groups with distinct profiles of smoking. One group displayed hardly any or no smoking at all; a second group showed a trajectory of increased smoking; and a third group that showed high smoking rates initially and increased in smoking intensity over time. Results support the assumption of the selection model that the link between disruptive peers and smoking is spurious and due to shared variances with own early disruptiveness. Moreover, support was found for the popularity-socialization model supporting the assumption that age-related increases in social status are associated with smoking.

CONCLUSIONS

The findings emphasize that early disruptiveness is predictive of later smoking. In addition, it was shown that smoking becomes less deviant over time, in line with group norms. Future prevention programmes should emphasize the need to change these norms.

The relationship between local clean indoor air policies and smoking behaviours in Minnesota youth

BACKGROUND

While clean indoor air (CIA) policies are intended to reduce exposure to second-hand smoke in the workplace, restrictions in public workplaces have the potential to discourage youth smoking. There is growing evidence from cross-sectional and ecological studies, but limited evidence from longitudinal studies that this is so.

OBJECTIVE

To evaluate the association between local CIA policies and smoking behaviours among Minnesota youth over time.

DESIGN, SETTING AND SUBJECTS

A cohort of 4233 Minnesota youths, ages 11 to 16 at baseline, was interviewed via telephone for 6 years (2000-2006). Individual, family and community level variables were collected from participants every 6 months. A generalised estimating equation (GEE) logistic regression was used to assess the relationship between CIA policies and past-month smoking in youth over time. The analysis was controlled for potential confounders at individual and community levels.

RESULTS

There was not significant association between CIA policies and youth smoking behaviours in the multivariate analyses. At the individual level, parental smoking significantly increased the odds of smoking nearly 40% and close friend smoking increased the odds of past-month smoking by nearly 100% for each close friend. Banning smoking in the home was significantly associated with a 12% reduction in the odds of past-month smoking.

CONCLUSION

After accounting for other community and individual level factors known to be associated with youth smoking, there was no significant association between CIA policies and past-month smoking for youth over time.

Nicotine dependence symptoms among young never-smokers exposed to secondhand tobacco smoke

BACKGROUND

To extend previous observations that secondhand tobacco smoke (SHS) is associated with nicotine markers in children, we investigated if SHS exposure is associated with self-reports of nicotine dependence (ND) symptoms among young never-smokers.

METHOD

Data on number of persons who smoke inside the home, number of days exposed to SHS in a motor vehicle in the past week, number of parents, siblings, and friends who smoke, and ND symptoms, were collected from 10-12 year-old students in self-report questionnaires. The association between SHS and ND symptoms among young never-smokers was assessed in logistic regression models.

RESULTS

Sixty-nine of 1488 never-smokers (5%) reported one or more ND symptom. After controlling for sibling and peer smoking, and susceptibility to initiating smoking, exposure to SHS in a motor vehicle was independently associated with ND symptoms (OR, 95% CI=1.2, 1.0-1.4). The OR for number of persons who smoke inside the home was 1.1 (0.9-1.4).

CONCLUSION

SHS exposure in motor vehicles may be associated with ND symptoms among young never-smokers. If replicated, this finding provides support for interventions that promote non-smoking in motor vehicles.

Developmental trajectories of criteria of nicotine dependence in adolescence

We describe the nature and predictors of developmental trajectories of symptoms of DSM-IV nicotine dependence in adolescence following smoking initiation. Data are from a longitudinal cohort of 324 new smokers from grades 6-10 in the Chicago Public Schools, interviewed 5 times at 6-month intervals. Monthly data on DSM-IV symptoms of nicotine dependence were available for 36 months. Growth mixture modeling was applied to the monthly histories to identify trajectories of DSM-IV criteria of nicotine dependence. A four-class solution best fitted the data: no DSM criterion (47.7%); early onset/chronic course (19.8%); early onset/remission (17.3%); late onset (15.2%). Blunt use prior to cigarette use was associated with the three symptomatic trajectories. Conduct disorder and prior heavy smoking were associated with Class 2 (chronic). Conduct disorder differentiated Class 2 from Class 4 (late onset), while pleasant initial sensitivity to the first tobacco experience was associated with Classes 2 and 3 (remit) and differentiated Class 2 from Class 4. Novelty seeking characterized Class 3. Parental dependence differentiated chronicity (Class 2) from remission (Class 3) among those who developed symptoms early. Being Hispanic reduced membership in Classes 3 and 4, and being male for Class 3. The data highlight the importance of parental nicotine dependence as a risk factor for early and sustained nicotine dependence by the offspring, pleasant initial sensitivity and conduct disorder for early onset of dependence, and blunt use prior to smoking for all trajectories. The factors important for onset of dependence are not necessarily the same as those for sustained course.

The developmental trajectories of attention focusing, attentional and behavioral persistence, and externalizing problems during school-age years

The developmental trajectories of attention focusing (by parents' and teachers' reports) and attentional and behavioral persistence (observed during a laboratory task)--2 indexes of effortful control--and externalizing problems from ages 5 to 10 years were examined for 356 children combined from a pair of 3-wave (2 years apart) longitudinal studies. The authors identified clusters of children with distinct trajectories for these variables and examined the links between the effortful control trajectories and the externalizing problem trajectories. Although attention focusing remained relatively stable, attentional and behavioral persistence continued to show mean-level changes (especially among the children with lower levels of persistence). Children with high and stable trajectories of effortful control tended to exhibit low and stable trajectories of externalizing problems, whereas those with lower and/or less stable trajectories of effortful control showed more elevated and/or fluctuating trajectories of externalizing problems.

Personality risk factors associated with trajectories of tobacco use

The purpose of this longitudinal, prospective study was to evaluate trajectories of smoking in a cohort of African-American and Puerto Rican young adults and describe personality and behavioral factors associated with specific smoking trajectory group membership. Participants consisted of African-American and Puerto Rican male and female young adults (N = 451, mean age 26) from an inner-city community. Data were collected at four time points over a period of 13 years using structured interviews. Interviews took place within the schools and the participants' homes. Scales with adequate psychometric properties were adapted from previously validated measures. Variables that were examined for this study came from the domains of internalizing behaviors, externalizing behaviors, drug use, and demographic information. Data were analyzed using latent growth mixture modeling to explore discrete smoking trajectories. Logistic regression analyses were then used to examine the risk factors associated with the various smoking trajectory groups. Four trajectory groups were determined to best fit the data: nonsmokers, maturing-out smokers, late-starting smokers, and early-starting continuous smokers. Subjects who were unconventional, experienced intrapersonal distress, and used alcohol and illegal drugs were more likely to belong to one of the smoking trajectory groups than to the nonsmoking group. The early-starting continuous group scored highest on these personal risk attributes. The long-term impact of unconventional behavior, intrapersonal distress, and drug use on developmental trajectories of smoking support the importance of early intervention and prevention.

Youth tobacco use: a global perspective for child health care clinicians

Tobacco dependence, responsible for approximately 4 million annual deaths worldwide, is considered to be a "pediatric disease." The smoking epidemic is spreading rapidly in developing countries. Factors contributing to youth smoking in developing countries include cultural traditions, tobacco's easy accessibility and moderate pricing, peer and family influences, and tobacco companies' advertisements and promotional activities. Secondhand tobacco smoke exposure is a substantial problem that causes increased rates of pneumonia, otitis media, asthma, and other short- and long-term pediatric conditions. Parental tobacco use results in children's deprivation of essential needs such as nutrition and education. In this article we review contemporary evidence with respect to the etiology of nicotine dependence among youth, the forms of youth tobacco products worldwide, global youth tobacco-control efforts to date, medical education efforts, and child health care clinicians' special role in youth tobacco-control strategies. In addition, we provide a review of currently available funding opportunities for development and implementation of youth tobacco-control programs.

Genetic and Cultural Transmission of Smoking Initiation: An Extended Twin Kinship Model

BACKGROUND

Considerable evidence from twin and adoption studies indicates that genetic and shared environmental factors play a significant role in the initiation of smoking behavior. Although twin and adoption designs are powerful to detect genetic and environmental influences, they do not provide information on the processes of assortative mating and parent-offspring transmission and their contribution to the variability explained by genetic and/or environmental factors.

METHODS

We examined the role of genetic and environmental factors for smoking initiation using an extended kinship design. This design allows the simultaneous testing of additive and non-additive genetic, shared and individual-specific environmental factors, as well as sex differences in the expression of genes and environment in the presence of assortative mating and combined genetic and cultural transmission. A dichotomous lifetime smoking measure was obtained from twins and relatives in the Virginia 30,000 sample.

RESULTS

Results demonstrate that both genetic and environmental factors play a significant role in the liability to smoking initiation. Major influences on individual differences appeared to be additive genetic and unique environmental effects, with smaller contributions from assortative mating, shared sibling environment, twin environment, cultural transmission and resulting genotype-environment covariance. The finding of negative cultural transmission without dominance led us to investigate more closely two possible mechanisms for the lower parent-offspring correlations compared to the sibling and DZ twin correlations in subsets of the data: (i) age x gene interaction, and (ii) social homogamy. Neither mechanism provided a significantly better explanation of the data, although age regression was significant.

CONCLUSIONS

This study showed significant heritability, partly due to assortment, and significant effects of primarily non-parental shared environment on smoking initiation.

The incidence of smoking and risk factors for smoking initiation in medical faculty students: cohort study

BACKGROUND

Medical education requires detailed investigation because it is a period during which the attitudes and behaviors of physicians develop. The purpose of this study was to calculate the yearly smoking prevalence and incidence rates of medical faculty students and to identify the risk factors for adopting smoking behaviour.

METHODS

This is a cohort study in which every student was asked about their smoking habits at the time of first registration to the medical faculty, and was monitored every year. Smoking prevalence, yearly incidence of initiation of smoking and average years of smoking were calculated in analysis.

RESULTS

At the time of registration, 21.8% of the students smoked. At the end of six years, males had smoked for an average of 2.6 +/- 3.0 years and females for 1.0 +/- 1.8 years (p < 0.05). Of the 93 medical students who were not smokers at the time of registration, 30 (32.3%) were smokers at the end of the 6 years of the course.

CONCLUSION

The first 3 years of medical education are the most risky period for initiation of smoking. We found that factors such as being male, having a smoking friend in the same environment and having a high trait anxiety score were related to the initiation of smoking. Targeted smoking training should be mandatory for students in the Medical Faculty.