Risk factors for adolescent smoking: parental smoking and the mediating role of nicotine dependence

Risk factors for smoking in adolescence: evidence from a cross-sectional survey in Switzerland

BACKGROUND

Cigarette smoking during adolescence is a major public health concern with far-reaching health implications. Adolescents who smoke are at an increased risk of developing long-term health problems and are more likely to continue smoking into adulthood. Therefore, it is vital to identify and understand the risk factors that contribute to adolescent smoking - which in turn facilitate the development of targeted prevention and intervention programs.

METHODS

Data was drawn from a cross-sectional survey conducted between October and December 2021, encompassing adolescents of adolescents aged 14 to 19 residing in Switzerland (n = 2,683). Multiple logistic regression analysis was employed to explore which demographic, household, behavioural and psychographic factors are associated with current smoking status.

RESULTS

The regression results showed higher odds of smoking for female respondents (OR 1.39; p-value 0.007); older adolescents (OR 1.30; p-value < 0.001); those living in the French-speaking part of Switzerland (OR 1.39; p-value 0.021), in suburban areas (OR 1.35; p-value 0.023) and with a smoker in the same household (OR 2.41; p-value < 0.001); adolescents consuming alcohol (OR 4.10; p-value < 0.001), cannabis products (OR 6.72; p-value < 0.001) and hookah (OR 5.07; p-value < 0.001) at least once a month; respondents not engaging in sports (OR 1.90; p-value < 0.001) or music (OR 1.42; p-value 0.031) as top five leisure activities and those experiencing high stress levels at home (OR 1.74; p-value < 0.001). Adolescents with high scores in health awareness (OR 0.33; p-value < 0.001), on the relational self-esteem scale (OR 0.78; p-value 0.054) and on the general well-being scale (OR 0.52; p-value 0.022) were less likely to smoke than their counterparts with lower scores. High risk-seeking was associated with higher odds of smoking (OR 2.15; p-value < 0.001).

CONCLUSIONS

Our results suggest the importance of a comprehensive approach at both individual and institutional levels to reduce smoking rates in adolescents. More specifically, a holistic strategy that encompasses adolescents, families, schools and policymakers ranging from strengthening adolescents' self-esteem, smoking cessation support for parents, to increasing engagement in musical and physical activities, and enhancing health awareness in the school curriculum.

Pubertal development at age 14 is associated with male adolescents' combustible cigarette smoking and dual use, but not with e-cigarette use - Findings from the UK Millennium Cohort Study

BACKGROUND

Adolescent nicotine exposure via electronic cigarettes (e-cigarettes) is a global health concern. Pubertal development earlier than peers increases the risk of tobacco smoking compared to peers experiencing on-time or late maturation, yet relationships of pubertal timing with e-cigarettes are unknown. We examine whether early pubertal timing is associated with risk for e-cigarette use, tobacco cigarettes, or both by age 14.

METHODS

The Millennium Cohort Study follows a representative cohort of 18,552 9-month-old children born 2000-2002 in the United Kingdom. Our sample includes 11,445 adolescents (5697 boys, 5748 girls) classified at age 14 as early, on-time, or late in pubertal development timing (PDT) relative to same-age, same-sex peers using the Pubertal Development Scale. Outcomes were use of e-cigarettes, tobacco cigarettes, or both by age 14. We included childhood liability confounders and demographics measured from age 7-11.

RESULTS

For girls, no PDT differences in age 14 e-cigarette or tobacco cigarette use were observed. All relative to on-time PDT boys, early maturing boys' odds of tobacco cigarette use were 59% higher (OR=1.59, 95% confidence interval (CI)=1.08,2.35), and odds of dual-use were 49% higher (OR=1.49, CI=1.11,1.99), both compared to odds of never use. Among late PDT boys, dual-use odds were lower than never use by 35% (OR=0.65, CI=0.47,0.91) and lower than e-cigarette use only by 36% (OR=0.64, CI=0.42,0.97).

CONCLUSIONS

At age 14, PDT was not associated with e-cigarette use for either sex, yet it was linked with tobacco use and dual use among boys.

Roles of parental smoking and family structure for the explanation of socio-economic inequalities in adolescent smoking

BACKGROUND AND AIMS

Among European countries, France is particularly concerned by adolescent tobacco smoking, especially in disadvantaged socio-economic backgrounds (SES). We measured the respective contributions of parental smoking and family living arrangement to social disparities in smoking during adolescence.

DESIGN

Secondary analysis of survey data.

SETTING

A cross-sectional nation-wide exhaustive 12-day survey in March 2017 of French youth aged 17-18.5 years participating in the national mandatory civic information day.

PARTICIPANTS

A total of 13 314 adolescents answering a pen-and-paper questionnaire about their own tobacco consumption and the smoking of their parents.

MEASUREMENTS

Risk ratios (RRs) were computed using modified Poisson regressions, and population-attributable fraction (PAF) was used as a measure of the explanatory roles of the different factors as mediators of SES.

FINDINGS

Adolescents living within very privileged and privileged SES were significantly less likely to report daily tobacco smoking (20.4 and 22.7%, respectively) than those within modest and disadvantaged ones (26.0 and 28.6%, respectively). Parental smoking and family living arrangement independently explained the smoking inequalities among adolescents. After adjusting for schooling factors, the risks associated with parental smoking ranged between RR = 1.64 [95% confidence interval (CI) = 1.50-1.79] when the father only smoked and RR = 2.17 (95% CI = 1.99-2.36) when both parents smoked, compared with non-smoking parents; the risk associated with living in a non-intact family was 1.35 (95% CI = 1.26-1.43) and that of living outside the parental home was 1.20 (95% CI = 1.10-1.30). Apprentices and adolescents out of school had higher risks than those at school (RR = 1.82, 95% CI = 1.68-1.98) and RR = 2.10, 95% CI = 1.92-2.29). The contribution of parental smoking to adolescent smoking (PAF = 32%) was greater than that of SES (PAF = 9%), family living arrangement (PAF = 17%) or schooling factors (14%). The share of SES decreased from 18 to 9% when considering these mediating factors.

CONCLUSION

In France, parental smoking appears to be the factor that most influences adolescent smoking, followed by family living arrangement; the role of family socio-economic status is small in comparison.

Paternal nicotine taking elicits heritable sex-specific phenotypes that are mediated by hippocampal Satb2

Nicotine intake, whether through tobacco smoking or e-cigarettes, remains a global health concern. An emerging preclinical literature indicates that parental nicotine exposure produces behavioral, physiological, and molecular changes in subsequent generations. However, the heritable effects of voluntary parental nicotine taking are unknown. Here, we show increased acquisition of nicotine taking in male and female offspring of sires that self-administered nicotine. In contrast, self-administration of sucrose and cocaine were unaltered in male and female offspring suggesting that the intergenerational effects of paternal nicotine taking may be reinforcer specific. Further characterization revealed memory deficits and increased anxiety-like behaviors in drug-naive male, but not female, offspring of nicotine-experienced sires. Using an unbiased, genome-wide approach, we discovered that these phenotypes were associated with decreased expression of Satb2, a transcription factor known to play important roles in synaptic plasticity and memory formation, in the hippocampus of nicotine-sired male offspring. This effect was sex-specific as no changes in Satb2 expression were found in nicotine-sired female offspring. Finally, increasing Satb2 levels in the hippocampus prevented the escalation of nicotine intake and rescued the memory deficits associated with paternal nicotine taking in male offspring. Collectively, these findings indicate that paternal nicotine taking produces heritable sex-specific molecular changes that promote addiction-like phenotypes and memory impairments in male offspring.

Estimating causal and time-varying effects of maternal smoking on youth smoking

INTRODUCTION

Maternal smoking is a well-known risk factor for youth smoking, yet whether this relationship is causal remains unresolved. This study utilizes propensity score methods for causal inference to robustly account for shared risk factors between maternal and offspring smoking.

METHODS

An 8-year longitudinal cohort of 900 adolescents in the Chicago area were followed starting from approximately age 15.6. The effects of maternal lifetime smoking (MLS) and prenatal tobacco exposure (PTE) (among participants reporting MLS) on offspring's past 30-day smoking, daily smoking status and smoking frequency were examined using logistic regression and Poisson regression after nearest-neighbor propensity matching. Age dependency of this relationship was then examined across the age range of 15-25 using time-varying effect modeling.

RESULTS

Propensity matching yielded 438 and 132 pairs for MLS and PTE study samples, respectively. MLS demonstrated significant associations with past 30-day smoking (RR 1.09; 95% CI 1.04-1.14), daily smoking (RR 1.08; 95% CI 1.05-1.12), and smoking frequency of offspring (RR 1.32; 95% CI 1.15-1.52), with stable effects across age. Among participants reporting MLS, having PTE showed significant additional effects on daily smoking (RR 1.09; 95% CI 1.02-1.17) and age-dependency that showed significance during young adulthood but not adolescence.

CONCLUSION

The relationship between maternal and offspring smoking was not fully accounted for by shared risk factors, suggesting possible causation with PTE having a delayed effect across age. Targeted prevention efforts should be made on maternal smoking-exposed adolescents to mitigate their risks of developing heavy smoking habits in adulthood.

Communication About Adolescent and Caregiver Smoking and Vaping During Pediatric Asthma Visits: Implications for Providers

INTRODUCTION

Although rates of cigarette smoking among U.S. adolescents have declined, rates of vaping (i.e., using e-cigarettes) have increased. We conducted a secondary analysis of 359 transcripts of medical visits of adolescents with asthma to examine communication about caregiver and adolescent smoking and vaping.

METHOD

Adolescents aged 11-17 years with persistent asthma and their parents were enrolled from four pediatric clinics in 2015-2017. Youth were randomized to the intervention or usual care groups. Intervention group adolescents watched a video and then completed an asthma question prompt list before their visits.

RESULTS

Forty providers and 359 patients participated. Providers, adolescents, and caregivers discussed smoking during 38.2% of their visits. Vaping was never discussed.

DISCUSSION

There is room to improve how often providers in a primary care setting discuss smoking and vaping. Further investigation might focus on how a smoking and vaping prompt list for adolescents could increase tobacco discussions during visits.

The effect of maternal smoking on offspring smoking is unrelated to heritable personality traits or initial subjective experiences

INTRODUCTION

Maternal smoking is a risk factor for offspring smoking. Lifetime maternal smoking vs. prenatal tobacco exposure (PTE) appear to act through different mechanisms. This study tested the hypothesis that maternal smoking measures' effects on offspring smoking could be attributable to hereditary mechanisms: personality traits (novelty-seeking, impulsivity, neuroticism, self-esteem) and initial subjective smoking experiences (pleasurable, unpleasurable, dizziness).

METHODS

Data were drawn from the Social and Emotional Contexts of Adolescent Smoking Patterns (SECASP) study, an 8-year longitudinal study of 9 th or 10 th graders at baseline (≈age 15) who experiment with smoking (<100 lifetime cigarettes; N=594) at baseline. Young adult smoking frequency at the 8-year follow-up (≈age 23) was examined as a function of baseline characteristics (heritable trait, maternal smoking, PTE, sex) and baseline smoking frequency and nicotine dependence. Structural equation models determined whether inclusion of each heritable trait among offspring confounded the effects of maternal smoking (PTE or maternal smoking) on offspring smoking and nicotine dependence.

RESULTS

Impulsiveness was associated with intermediate adolescent smoking frequency (B=0.135, SD=0.043 p=0.002) and nicotine dependence (B=0.012, SD=0.003, p<0.001). Unpleasurable first experience (B=0.886, SD=0.374, p=0.018) and dizziness (B=0.629, SD=0.293, p=0.032) showed a trend with intermediate smoking frequency that was non-significant after correcting for multiple comparisons. These traits did not confound maternal smoking's effects.

CONCLUSIONS

None of the heritable traits examined in this model explained the effect of maternal smoking measures on adolescence or young adulthood offspring smoking. Further research is needed to elucidate the mechanism by which PTE and maternal smoking are linked to offspring smoking.

Tobacco-Related Counseling and Documentation in Adolescent Primary Care Practice: Challenges and Opportunities

INTRODUCTION

Primary care visits present an opportunity to reduce tobacco use and tobacco smoke exposure (TSE) among adolescents. To date, few studies have examined tobacco-related electronic health record (EHR) documentation in adolescent visits. The purpose of this study was to (1) describe tobacco-related EHR documentation practices in adolescent care clinics, including whether alternative tobacco products, parental use, and TSE were addressed; and (2) identify aspects of adolescent tobacco use that may inform EHR updates and counseling and documentation practices.

METHODS

Following a convergent mixed-methods design, we conducted an EHR review of 508 adolescent well-child visits, performed focus groups with pediatric providers and staff, and conducted in-depth interviews with adolescent patients. Record review data and interview transcripts were analyzed and interpreted concurrently.

RESULTS

In the EHR review, cigarette screening was documented in 92.3% of visits, smokeless tobacco screening in 51.4%, parental tobacco use in 23.2%, and home TSE in 33.1% of visits. Smoking status options were not mutually exclusive and did not include noncigarette products. No records documented assessment of e-cigarette use, despite nearly half of adolescent interview respondents citing these as the most popular products among adolescents. In interviews, adolescents discussed their experiences with alternative tobacco/nicotine products more than cigarettes.

CONCLUSIONS

Tobacco use status prompts should be revised for clarity and include noncigarette tobacco products and TSE. Provider education on noncigarette products and TSE assessment is needed. Improvements in EHR systems, resources, and tools can lead to better tobacco screening, prevention, and treatment practices among primary care providers.

IMPLICATIONS

Clinical guidelines call for pediatricians to assess and treat adolescent and parental tobacco use during primary care visits. The use of electronic health records (EHRs) can improve screening and counseling practices; however, few studies have examined tobacco-related EHR documentation practices in adolescent care settings. This mixed-methods study found low rates of EHR documentation related to noncigarette nicotine/tobacco products, parental tobacco use, and tobacco smoke exposure. These results demonstrate the need for increased provider training and EHR modifications to facilitate comprehensive tobacco control efforts in the adolescent population.

Cigarette, shisha, and electronic smoking and respiratory symptoms in Swiss children: The LUIS study

BACKGROUND

Smoking habits in adolescents are changing. We assessed active smoking of conventional cigarettes, e-cigarettes and shishas in Swiss schoolchildren, studied risk factors and compared respiratory problems between smokers and non-smokers.

METHODS

We used data from LuftiBus in the school (LUIS), a school-based survey of respiratory health of children carried out 2013 to 2016 in the canton of Zurich, Switzerland. Participants were asked about use of cigarettes, shishas, and electronic smoking devices (ESD), and current respiratory symptoms. We studied associations between smoking and risk factors using logistic regression.

RESULTS

We included 3488 schoolchildren. Among 6 to 12-year-olds, 90/1905 (5%) had smoked occasionally (<once/week). Among 13 to 17-year-olds, 563/1583 (36%) had smoked occasionally of whom 414 smoked ESDs, 409 shishas, and 276 cigarettes. Among 13 to 17-year-olds who smoked frequently (≥once/week), 41/54 (76%) smoked cigarettes. A 22% of 15 to 17-year-olds (104/477) had used all three products. Smoking was more common in adolescents who were male (adjusted OR, 2.1; 95% CI, 1.7-2.6), lived in rural areas (1.8, 95% CI, 1.2-2.9 vs small urban), and whose mother (1.7, 95% CI, 1.3-2.3) or father (1.5, 95% CI, 1.2-1.9) smoked. Current respiratory symptoms like rhinitis, dyspnea, and wheeze were more common among frequent smokers (44%, 30%, 12%, respectively) and occasional smokers (32%, 22%, 13%) than in never smokers (29%,19%, 8%, P for trend <.05).

CONCLUSION

Smoking of shishas and ESDs is common among Swiss adolescents and often combined with smoking cigarettes. Adolescent smokers reported more respiratory symptoms than never smokers. We recommend smoking preventive strategies that include all forms of smoking.

The Enduring Effects of Parental Alcohol, Tobacco, and Drug Use on Child Well-being: A Multilevel Meta-Analysis

The effects of psychoactive substance abuse are not limited to the user, but extend to the entire family system, with children of substance abusers being particularly at risk. This meta-analysis attempted to quantify the longitudinal relationship between parental alcohol, tobacco, and drug use and child well-being, investigating variation across a range of substance and well-being indices and other potential moderators. We performed a literature search of peer-reviewed, English language, longitudinal observational studies that reported outcomes for children aged 0 to 18 years. In total, 56 studies, yielding 220 dependent effect sizes, met inclusion criteria. A multilevel random-effects model revealed a statistically significant, small detriment to child well-being for parental substance abuse over time (r = .15). Moderator analyses demonstrated that the effect was more pronounced for parental drug use (r = .25), compared with alcohol use (r = .13), tobacco use (r = .13), and alcohol use disorder (r = .14). Results highlight a need for future studies that better capture the effect of parental psychoactive substance abuse on the full breadth of childhood well-being outcomes and to integrate substance abuse into models that specify the precise conditions under which parental behavior determines child well-being.Registration: PROSPERO CRD42017076088.

Addressing Ethnic Disparities in Adolescent Smoking: Is Reducing Exposure to Smoking in the Home a Key?

INTRODUCTION

Smoking among New Zealand (NZ) adolescents has declined since 2000, but ethnic disparities remain pronounced. To inform prevention efforts, we investigated exposure to and relative importance of known predictors of adolescent smoking and how these have changed over time, for Māori (NZ's indigenous population) and adolescents overall.

METHODS

We used repeat cross-sectional data, 2003-2015, from a national survey of 14- to 15-year olds (N = 20 443-31 696 per year). For the overall sample and for Māori and non-Māori, we calculated adjusted odds ratios (aORs) to assess the association between regular smoking and risk factors each year: one or more parents smoke, best friend smokes, older sibling(s) smoke, and past week exposure to smoking in the home. We calculated population attributable risk (PAR) for risk factors in 2003 and 2015.

RESULTS

Between 2003 and 2015, aORs for exposure to smoking in the home increased from 1.7 (95% CI 1.6% to 1.8%) to 2.6 (2.1% to 3.1%) overall and from 1.8 (1.6% to 2.1%) to 3.4 (2.5% to 4.5%) for Māori; aORs for "best friend smokes" also increased, while aORs for sibling smoking and parental smoking did not change meaningfully. PAR for exposure to smoking in the home increased from 17% to 31% overall and from 28% to 57% for Māori, while PARs for other risk factors decreased.

CONCLUSIONS

Exposure to smoking in the home has become more strongly associated with adolescent smoking over time and is an increasingly important risk factor at the population level (independent of parental smoking), particularly for Māori.

IMPLICATIONS

Our findings have implications for reducing smoking uptake and ethnic disparities in NZ, and potentially elsewhere, given the similarity in risk factors and trends for adolescent smoking internationally. Our findings suggest that reducing second-hand smoke exposure in homes will likely reduce uptake of smoking. Because Māori children are both more exposed and appear to be more strongly influenced by exposure to smoking in the home, interventions to reduce indoor smoking could have differentially positive effects for Māori. Greater research and policy attention to reducing smoking in homes is warranted.

Preoperative vaping prevalence and behavior of French surgical patients: A multicentre study

INTRODUCTION

Prevalence and tobacco-related perioperative complications have been largely reported. The impact of vaping (e-cigarette use) on the perioperative period has been rarely evaluated. The purpose of this multicentre cross-sectional survey was to assess the prevalence of vaping and behaviour of patients undergoing elective surgery.

METHODS

After institutional review board committee and patient approvals, patients (aged ≥18 years) scheduled for elective non-cardiac surgery in six French hospitals were assessed preoperatively. Demographic characteristics, and information on vaping, smoking or dual-use status and consumption were reported.

RESULTS

In six centres, 1712 eligible patients were approached and 1664 patients were included in this study from June 2016 to January 2017. Of these, 62 patients used e-cigarettes in the preoperative period (3%; 95% CI: 2–4), including 24 exclusive e-cigarette users (1%; 95% CI: 1–2), 38 dual-users (2%; 95% CI: 2–3) and 365 smokers (22%; 95% CI: 20–24). Vapers were older than smokers (53 vs 47 years old; p=0.01). During the preoperative period, 12 patients (1%) reported vaping the morning of surgery.

CONCLUSIONS

In the preoperative period, vaping was ten-fold less prevalent than smoking. Although the clinical relevance may be weak, further research is needed to explore the real impact of vaping on patients’ outcomes and to elaborate on clinical recommendations.

Time-varying effects of family smoking and family management on adolescent daily smoking: The moderating roles of behavioral disinhibition and anxiety

BACKGROUND

Family smoking environment and family management are associated with risk of teen smoking behaviors. However, less is known about whether these associations increase or decrease in strength across adolescence, and whether there are person-environment interactions. The current study examined 1) the age-varying main effects of family smoking and family management on adolescent daily smoking from ages 12-18 and tested 2) whether behavioral disinhibition and anxiety moderated these relationships.

METHODS

Data were drawn from the Seattle Social Development Project (SSDP; N = 808), a longitudinal study examining prosocial and antisocial behavior. Analyses used time-varying effect modeling (TVEM), which tested the stability of the relationship between family smoking and family management and youth daily smoking across adolescence.

RESULTS

Greater family smoking increased the likelihood of adolescent daily smoking, whereas greater family management reduced the likelihood of daily smoking. Significant interactions between family management and youth behavioral disinhibition and anxiety during early and mid-adolescence indicated that family management was more protective for adolescents with low (compared to high) behavioral disinhibition and anxiety. The effect of family smoking was not moderated by behavioral disinhibition or anxiety.

CONCLUSIONS

Family smoking and family management are key risk and protective factors that may be targeted for adolescent smoking prevention. Our interaction results for individual differences in behavioral disinhibition and anxiety suggest that certain types of youth may respond differently to family management practices. Findings also show periods during adolescence where family-centered preventive interventions could be optimally timed to prevent or reduce persistent adolescent smoking.

Determinants of mental health and abuse of psychoactive substances associated with tobacco use. A case-control study

This study aimed to estimate the strength of association among smokers with variables regarding mental health, family functionality, and use of other psychoactive substances. This is a case-control observational study developed from March to November 2016. The study was conducted in a Brazilian Midwest municipality with 646 subjects, of which 323 were cases. In the model, the case group comprised subjects with a certain degree of tobacco dependence. The control group included subjects that were not exposed to tobacco. Concerning tobacco use time, the mean exposure of the case group was 25.65 years. In the multiple logistic regression analysis model the following were positively associated: non-white skin color (p = 0.002); years of study ≤ 8 (p < 0.001); having children (p < 0.001); informal work (p = 0.024); not having a health plan (p < 0.001); high family dysfunction (p = 0.007); AUDIT ≥ 8 (p < 0.001); depression (p < 0.001); having illicit drug in lifetime (p < 0.001); living with other people (p = 0.003) and no religion (p = 0.001). This study reinforces the vulnerability of smokers, associating variables correlated to the field of mental health, and innovates by discussing the influence of family relationships on nicotinic dependence.

The Role of Nicotine Dependence in E-Cigarettes' Potential for Smoking Reduction

Introduction

E-cigarettes (Electronic Nicotine Delivery Systems, or ENDS) are an increasingly popular tobacco product among youth. Some evidence suggests that e-cigarettes may be effective for harm reduction and smoking cessation, although these claims remain controversial. Little is known about how nicotine dependence may contribute to e-cigarettes' effectiveness in reducing or quitting conventional smoking.

Methods

A cohort of young adults were surveyed over 4 years (approximately ages 19-23). Varying-coefficient models (VCMs) were used to examine the relationship between e-cigarette use and conventional smoking frequency, and how this relationship varies across users with different nicotine dependence levels.

Results

Lifetime, but not recent, e-cigarette use was associated with less frequent concurrent smoking of conventional cigarettes among those with high levels of nicotine dependence. However, nondependent e-cigarette users smoked conventional cigarettes slightly more frequently than those who had never used e-cigarettes. Nearly half of ever e-cigarette users reported using them to quit smoking at the last measurement wave. For those who used e-cigarettes in a cessation attempt, the frequency of e-cigarette use was not associated with reductions in future conventional smoking frequency.

Conclusions

These findings offer possible support that e-cigarettes may act as a smoking reduction method among highly nicotine-dependent young adult cigarette smokers. However, the opposite was found in non-dependent smokers, suggesting that e-cigarette use should be discouraged among novice tobacco users. Additionally, although a substantial proportion of young adults used e-cigarettes to help them quit smoking, these self-initiated quit attempts with e-cigarettes were not associated with future smoking reduction or cessation.

Implications

This study offers potential support for e-cigarettes as a smoking reduction tool among highly nicotine-dependent young adult conventional smokers, although the extent and nature of this remains unclear. The use of e-cigarettes as a quit aid was not associated with reductions in conventional smoking, consistent with most other quit aids in this sample except for nicotine replacement therapy, which was only effective for the most dependent smokers. Notably, these findings highlight the necessity of accounting for smokers' nicotine dependence levels when examining tobacco use patterns.

Smoking Trajectory Classes and Impact of Social Smoking Identity in Two Cohorts of U.S. Young Adults

This study describes cigarette smoking trajectories, the influence of social smoker self-identification (SSID), and correlates of these trajectories in two cohorts of U.S. young adults: a sample from the Chicago metropolitan area (Social Emotional Contexts of Adolescent and Young Adult Smoking Patterns [SECAP], n = 893) and a national sample (Truth Initiative Young Adult Cohort Study [YA Cohort], n = 1,491). Using latent class growth analyses and growth mixture models, five smoking trajectories were identified in each sample: in SECAP: nonsmoking (n = 658, 73.7%), declining smoking (n = 20, 2.2%), moderate/stable smoking (n = 114, 12.8%), high/stable smoking (n = 79, 8.9%), and escalating smoking (n = 22, 2.5%); and in YA Cohort: nonsmoking (n = 1,215, 81.5%), slowly declining smoking (n = 52, 3.5%), rapidly declining smoking (n = 50, 3.4%), stable smoking (n = 139, 9%), and escalating smoking (n = 35, 2.4%). SSID was most prevalent in moderate/stable smoking (35.5% SECAP), rapidly declining smoking (25.2% YA Cohort), and nonsmoking. Understanding nuances of how smoking identity is formed and used to limit or facilitate smoking behavior in young adults will allow for more effective interventions to reduce tobacco use.

Socioeconomic Trends in Adolescent Smoking in Finland From 2000 to 2015

PURPOSE

Smoking is a significant cause of morbidity and mortality worldwide. In the past decades, the prevalence of adolescent smoking has decreased in industrial countries. However, whether the decreasing trend can be seen across all socioeconomic groups is unknown. The aim of this study was to examine time trends in adolescent smoking according to the socioeconomic status among Finnish adolescents between 2000 and 2015.

METHODS

A population-based school survey was conducted biennially among 14- to 16-year-old Finns between 2000 and 2015 (n = 761,278). Distributions for frequent smoking, lifelong nonsmoking, and socioeconomic adversities (low parental education, not living with both parents and parental unemployment during the past year) were calculated. Associations were studied using binomial logistic regression results shown by odds ratios with 95% confidence intervals.

RESULTS

Frequent smoking was positively associated and lifelong nonsmoking was negatively associated with socioeconomic adversities. Over the study period, the overall prevalence of frequent smoking decreased and lifelong nonsmoking increased. However, no similar changes were observed among adolescents with most socioeconomic adversities.

CONCLUSION

Socioeconomic differences in adolescent smoking increased in Finland between 2000 and 2015. Although the overall prevalence of frequent smoking decreased, no similar decrease was observed among adolescents with most socioeconomic adversities. Similarly, although the overall prevalence of lifelong nonsmoking increased, this was not observed among adolescents with most socioeconomic adversities. Socioeconomic adversities should be considered in the prevention of adolescent smoking.

Satisfaction with job and family life, and association with smoking and alcohol drinking behaviors among young men in Malawi: analysis from a multiple indicator survey

Objective

The objective of the present study was to investigate if satisfaction with job and family life has any connection with smoking and alcohol drinking behavior among young men in Malawi.

Results

Results of multivariable logistic regression analysis indicate that compared to men who were unemployed, those who were dissatisfied were 0.90 times less likely to be non-smokers [OR = 0.90; 95% CI = 0.36–2.24], 0.83 times [OR = 0.83; 95% CI = 0.63–1.08] as likely to try drinking alcohol. Among those who reported being satisfied with job, the odds of trying alcohol was relatively more [OR = 0.77; 95% CI = 0.63–0.93], however the odds of cigarette smoking were less [OR = 1.05; 95% CI = 0.48–2.31] relative to those who were unemployed. Results also showed that not being satisfied with overall life increased the odds of smoking and alcohol drinking [OR = 0.60; 95% CI = 0.24–1.46] and [OR = 0.95; 95% CI = 0.72–1.24] respectively compared to those who were satisfied with overall life.

Why has adolescent smoking declined dramatically? Trend analysis using repeat cross-sectional data from New Zealand 2002-2015

OBJECTIVES

Adolescent smoking has declined in New Zealand and in many other countries since the late 1990s, yet the reasons for the decline are not well understood. We investigated the extent to which established risk factors for adolescent smoking (parental, sibling and peer smoking, and exposure to smoking in the home) explained the downward trend.

DESIGN

Trend analysis of repeat cross-sectional data from an annual nationally representative survey.

SETTING

New Zealand.

PARTICIPANTS

Secondary school students aged 14-15 (n=398 221).

OUTCOME MEASURE

Regular (at least monthly) smoking.

METHODS

For each risk factor (parental smoking, best friend smoking, older sibling smoking and past week exposure to smoking in the home) we plotted prevalence of exposure, 2002-2015. Next, using multivariable logistic regression, we modelled the trend in regular smoking (expressed as an OR for year) adjusting for age, sex, ethnicity and socioeconomic position. The risk factors were added to the model-individually and collectively-to test whether they attenuated the OR for year.

RESULTS

Exposure to all risk factors except 'past week exposure to smoking in the home' decreased between 2002 and 2015. We observed a strong downward trend in regular smoking among adolescents (OR=0.88 per year, 95% CI 0.88 to 0.88, p<0.001). 'Best friend smoking' was the only risk factor that significantly attenuated the trend. However, due to circularity, this factor provides an unsatisfactory explanation for population level smoking decline.

CONCLUSIONS

The established risk factors that we explored do not appear to have contributed to the remarkable decline in adolescent smoking in New Zealand between 2003 and 2015. Further research is needed to assess the possible contribution of factors outside our model, such as changes in the policy context, the social meaning of smoking and broader social and economic conditions.

The role of nicotinic receptor genes (CHRN) in the pathways of prenatal tobacco exposure on smoking behavior among young adult light smokers

BACKGROUND

Prenatal tobacco exposure (PTE) is associated with more frequent smoking among young, light smokers. Little is known about how nicotinic acetylcholine receptor (CHRN) genes may contribute to this relationship.

METHODS

Data were drawn from a longitudinal cohort of young light smokers of European ancestry (N = 511). Three single nucleotide polymorphisms (SNPs) among offspring, rs16969968 and rs6495308 in CHRNA5A3B4 and rs2304297 in CHRNB3A6, were analyzed with respect to whether they 1) predict PTE status; 2) confound the previously-reported effects of PTE on future smoking; 3) have effects on youth smoking frequency that are mediated through PTE; and 4) have effects that are moderated by PTE.

RESULTS

rs2304297 and rs6495308 were associated with increased likelihood and severity of PTE, respectively. In a path analysis, rs16969968 directly predicted more frequent smoking in young adulthood (B = 1.50, p = .044); this association was independent of, and not mediated by, PTE. The risk of rs16969968 (IRR = 1.07, p = .015) and the protective effect of rs2304297 (IRR = 0.84, p < .001) on smoking frequency were not moderated by PTE. PTE moderated the effect of rs6495308, such that these alleles were protective against later smoking frequency only among non-exposed youth (IRR = 0.85, p < .001).

CONCLUSIONS

The association between offspring CHRNB3A6 and PTE is a novel finding. The risk of rs16969968 on youth smoking is independent and unrelated to that of PTE among young, light smokers. PTE moderates the protective effect of rs6495308 on youth smoking frequency. However, PTE's pathway to youth smoking behavior was not explained by these genetic factors, leaving its mechanism(s) of action unclear.

Secondhand Smoke Exposure and Preclinical Markers of Cardiovascular Risk in Toddlers

OBJECTIVE

To investigate relationships between secondhand smoke exposure in young children and several preclinical markers of cardiovascular risk that have been established as relevant to adult populations.

STUDY DESIGN

There were 139 children, 2-5 years of age, enrolled in a cross-sectional study. Secondhand smoke exposure was objectively determined by hair nicotine level; a comprehensive panel of clinical markers (morning blood pressure, fasting glucose and insulin, lipid profiles, inflammation) and research markers (markers of oxidation, endothelial stress, and endothelial repair) of cardiovascular risk status were assessed. Univariate and multivariate linear regression were used to evaluate relationships between secondhand smoke exposure and cardiovascular risk markers.

RESULTS

Hair nicotine levels were correlated directly with blood pressure and serum C-reactive protein, and inversely correlated with serum high-density lipoprotein cholesterol and endothelial cell progenitor cell prevalence. In multivariate analyses, these relationships remained when controlled for age, sex, body mass index z-score, maternal education, and method of payment. Additionally, in multivariate analyses, hair nicotine level was significantly negatively correlated with total antioxidant capacity.

CONCLUSIONS

These results support the view that secondhand smoke exposure in the very young has a detectable relationship with several markers of cardiovascular risk, long before the emergence of clinical disease. Further studies to define mechanisms and strategies to prevent and mitigate these risks early in life are warranted.

Determinants of tobacco use by students

OBJECTIVE

Estimate the prevalence and determinants of tobacco use by students.

METHODS

This cross-sectional study, carried out between 2013 and 2014, evaluates 701 public school students between 10 and 79 years of age living in a city in the countryside of the State of Goias, Midwest of Brazil. A structured questionnaire collected the data and the predictor variables were demographic data, family nucleus, religion, physical activity practice, family functionality and parental smoking. Two multivariable models were implemented, the first for occasional tobacco use and the second for regular use, acquiring the measure of prevalence ratio (PR) and their respective 95%CI. Variables with p < 0.10 were included in Poisson regression models with robust variance to obtain the adjusted PR (adPR) and 95%CI. The Wald Chi-Squared test examined the differences between proportions, and values with p < 0.05 were statistically significant.

RESULTS

The prevalence of occasional and regular tobacco use were 33.4% (95%CI 29.8–36.9) and 6.7% (95%CI 5.0–8.8), respectively. The factors associated with occasional tobacco consumption were age of 15 to 17 years (adPR = 1.98) and above 18 years (adPR = 3.87), male gender (adPR = 1.23), moderate family dysfunction (adPR = 1.30), high family dysfunction (adPR = 1.97) and parental smoking (adPR = 1.60). In regards to regular consumption of tobacco, age above 18 years (adPR = 4.63), lack of religion (adPR = 2.08), high family dysfunction (adPR = 2.35) and parental smoking (adPR = 2.89) remained associated.

CONCLUSIONS

Students exhibit a high prevalence of occasional and regular tobacco use. This consumption relates to sociodemographic variables and family dysfunction.

Prenatal tobacco exposure, maternal postnatal nicotine dependence and adolescent risk for nicotine dependence: Birth cohort study

AIMS

The goals of this study are to determine if there is (a) a threshold effect for prenatal tobacco exposure (PTE) on adolescent risk for nicotine dependence, and (b) an additive effect of PTE and maternal postnatal nicotine dependence on adolescent risk for nicotine dependence.

METHODS

Pregnant women were recruited in their 4th or 5th gestational month and asked about cigarette use during the first trimester. Mothers reported on third trimester cigarette use at delivery. Sixteen years post-partum, mothers and offspring reported on current levels of cigarette use (N=784). Nicotine dependence was assessed in both using a modified Fagerström questionnaire.

RESULTS

Based on the results of a threshold analysis for PTE, four groups were created: threshold PTE only (10+ cigarettes per day), maternal nicotine postnatal dependence with no-low PTE (0-<10 cigarettes per day), threshold PTE+maternal postnatal nicotine dependence, and a referent group with no-low PTE and no maternal postnatal nicotine dependence. Adolescents in the PTE-only group and the PTE+maternal postnatal nicotine dependence group were significantly more likely to be at risk for nicotine dependence than the offspring from the referent group. However, there was no evidence for an additive effect of maternal postnatal nicotine dependence, and maternal nicotine dependence was not a significant predictor of adolescent risk for nicotine dependence in regression models including prenatal tobacco exposure.

CONCLUSIONS

Bivariate analysis revealed a threshold effect for PTE of 10 cigarettes per day. In multivariate analysis, PTE remained significantly related to risk for offspring nicotine dependence, after controlling for maternal postnatal nicotine dependence and other covariates associated with adolescent cigarette use.

Classification Tree Analysis as a Method for Uncovering Relations Between CHRNA5A3B4 and CHRNB3A6 in Predicting Smoking Progression in Adolescent Smokers

INTRODUCTION

Prior research suggests the CHRNA5A3B4 and CHRNB3A6 gene clusters have independent effects on smoking progression in young smokers. Here classification tree analysis uncovers conditional relations between these genes.

METHODS

Conditional classification tree and random forest analyses were employed to predict daily smoking at 6-year follow-up in a longitudinal sample of young smokers (N = 480) who had smoked at least one puff at baseline and were of European ancestry. Potential predictors included gender, lifetime smoking, Nicotine Dependence Syndrome Scale (NDSS), and five single nucleotide polymorphisms (SNPs) tagging CHRNB3A6 and CHRNA5A3B4 Haplotypes A, B, and C. Conditional random forest analysis was used to calculate variable importance.

RESULTS

The classification tree identified NDSS, the CHRNB3A6 SNP rs2304297, and the CHRNA5A3B4 Haplotype C SNP rs6495308 as predictive of year 6 daily smoking with the baseline NDSS identified as the strongest predictor. The CHRNB3A6 protective effect was contingent on a lower level of baseline NDSS, whereas the CHRNA5A3B4 Haplotype C protective effect was seen at a higher level of baseline NDSS. A CHRNA5A3B4 Haplotype C protective effect also was observed in participants with low baseline NDSS who had no CHRNB3A6 rs2304297 minor allele.

CONCLUSIONS

The protective effects of CHRNA5A3B4 Haplotype C and CHRNB3A6 on smoking progression are conditional on different levels of baseline cigarette use. Also, duplicate dominant epistasis between SNPs indicated the minor allele of either SNP afforded comparable protective effects in the absence of a minor allele at the other locus. Possible mechanisms underlying these conditional relations are discussed.

IMPLICATIONS

The substantive contributions of this paper are the demonstration of a difference in the protective effects of CHRNB3A6 and CHRNA5A3B4 Haplotype C in young smokers attributable to level of cigarette use, as well as observation of duplicate dominant epistasis between the two markers. The methodological contribution is demonstrating that classification tree and random forest statistical methods can uncover conditional relations among genetic effects not detected with more common regression methods.

Early-Emerging Nicotine Dependence Has Lasting and Time-Varying Effects on Adolescent Smoking Behavior

Novice and light adolescent smokers can develop symptoms of nicotine dependence, which predicts smoking behavior several years into the future. However, little is known about how the association between these early - emerging symptoms and later smoker behaviors may change across time from early adolescence into young adulthood. Data were drawn from a 7-year longitudinal study of experimental (<100 cigarettes/lifetime; N = 594) and light (100+ cigarettes/lifetime, but ≤5 cigarettes/day; N = 152) adolescent smokers. Time-varying effect models were used to examine the relationship between baseline nicotine dependence (assessed at age 15 ± 2 years) and future smoking frequency through age 24, after controlling for concurrent smoking heaviness. Baseline smoking status, race, and sex were examined as potential moderators of this relationship. Nicotine dependence symptoms assessed at approximately age 15 significantly predicted smoking frequency through age 24, over and above concurrent smoking heaviness, though it showed declining trends at older ages. Predictive validity was weaker among experimenters at young ages (<16), but stronger at older ages (20-23), relative to light smokers. Additionally, nicotine dependence was a stronger predictor of smoking frequency for white smokers around baseline (ages 14.5-16), relative to nonwhite smokers. Nicotine dependence assessed in mid-adolescence predicts smoking frequency well into early adulthood, over and above concurrent smoking heaviness, especially among novice smokers and nonwhite smokers. Early-emerging nicotine dependence is a promising marker for screening and interventions aimed at preventing smoking progression.

Oxidative Stress in Youth and Adolescents With Elevated Body Mass Index Exposed to Secondhand Smoke

INTRODUCTION

Our objective was to investigate the relationships between secondhand smoke (SHS) exposure and oxidative stress in a group of youth and adolescents with elevated body mass index.

METHODS

Participants in this cross sectional study were healthy nonsmoking youth and adolescents ages 9 to 18 years old. Three-quarters of the participants were either overweight or obese. SHS exposure was determined by survey and hair nicotine level. Markers of oxidation were total antioxidant capacity and protein malondialdehyde adducts (MDA).

RESULTS

Ninety subjects were studied; adequate hair samples were available for 86. The mean hair nicotine level was 0.75ng/mg, the median was 0.58ng/mg and the range was 0.09-2.88ng/mg. There was a significant relationship between MDA and the three survey questions regarding smoke exposure ([mother smokes, r = 0.29, P = .006], [smoker lives in the home, r = 0.31, P = .004], and [number of smokers in the home, r = 0.36, P = .002]). There was a significant positive relationship between log-hair nicotine and MDA (Pearson r = 0.233, P = .031), which remained significant after controlling for age, sex, race, and method of insurance. No relationship was found between log-hair nicotine and total antioxidant capacity. However, there was a significant relationship between number of smokers in the home (r = 0.24, P = .042) and total antioxidant capacity.

CONCLUSIONS

We have demonstrated a significant positive relationship hair nicotine level and MDA in a group of youth with a high proportion of overweight/obese subjects.

IMPLICATIONS

We have shown a significant relationship between objectively measured SHS exposure and one marker of oxidative stress in a sample of youth and adolescents with a high proportion of overweight/obese subjects, and who were nonsmokers with relatively low tobacco exposure. This finding remains significant after controlling for age, sex, race, and type of medical insurance. Since the cardiovascular effects of SHS exposure are related to oxidative stress, this finding adds to our knowledge that the sequence of deleterious effects of tobacco exposure on the cardiovascular system begins long before clinical disease is evident.

CYP2A6 Effects on Subjective Reactions to Initial Smoking Attempt

INTRODUCTION

In very novice smokers, CYP2A6 genotypes that reduce nicotine metabolism to an intermediate rate may increase smoking risk, relative to both normal and slow rates. The present study examined the hypothesis that intermediate metabolism variants are associated with greater pleasurable effects of the initial smoking attempt than either normal or slow metabolism variants.

METHODS

Participants were novice smokers (N = 261, 65% female) of European descent. Predicted nicotine metabolic rate based on CYP2A6 diplotypes (CYP2A6 Diplotype Predicted Rate [CDPR]) was partitioned into Normal, Intermediate, and Slow categories using a metabolism metric. Subjective reactions to the initial smoking attempt were assessed by the Pleasurable Smoking Experiences (PSE) scale, which was collected within 3 years of the initial smoking attempt. The effect of CDPR on PSE was tested using a generalized linear model in which CDPR was dummy coded and Intermediate CDPR was the reference condition. Gender was included in the model as a control for higher PSE scores by males.

RESULTS

Lower PSE scores were associated with Normal CDPR, β = -0.34, P = .008, and Slow CDPR, β = -0.52, P = .001, relative to Intermediate CDPR.

CONCLUSIONS

Intermediate CDPR-enhanced pleasurable effects of the initial smoking attempt relative to other CYP2A6 variants. This finding is consistent with the hypothesis that the risk effect of Intermediate CDPR on early smoking is a function of optimal pleasurable effects.

IMPLICATIONS

This study supports our recent hypothesis that CYP2A6 diplotypes that encode intermediate nicotine metabolism rate are associated with enhanced pleasurable events following the initial smoking attempt, compared with diplotypes that encode either normal or slow metabolism. This hypothesis was offered to account for our unexpected previous finding of enhanced smoking risk in very novice smokers associated with intermediate metabolism rate. Our new finding encourages further investigation of time-dependent relations between CYP2A6 effects and smoking motives, and it encourages laboratory study of the mechanisms underlying the initial smoking enhancement in novice smokers associated with intermediate metabolism.

Clinical Practice Policy to Protect Children From Tobacco, Nicotine, and Tobacco Smoke

Tobacco dependence starts in childhood. Tobacco exposure of children is common and causes illness and premature death in children and adults, with adverse effects starting in the womb. There is no safe level of tobacco smoke exposure. Pediatricians should screen for use of tobacco and other nicotine delivery devices and provide anticipatory guidance to prevent smoking initiation and reduce tobacco smoke exposure. Pediatricians need to be aware of the different nicotine delivery systems marketed and available.Parents and caregivers are important sources of children's tobacco smoke exposure. Because tobacco dependence is a severe addiction, to protect children's health, caregiver tobacco dependence treatment should be offered or referral for treatment should be provided (such as referral to the national smoker's quitline at 1-800-QUIT-NOW). If the source of tobacco exposure cannot be eliminated, counseling about reducing exposure to children should be provided.Health care delivery systems should facilitate the effective prevention, identification, and treatment of tobacco dependence in children and adolescents, their parents, and other caregivers. Health care facilities should protect children from tobacco smoke exposure and tobacco promotion. Tobacco dependence prevention and treatment should be part of medical education, with knowledge assessed as part of board certification examinations.

CYP2A6 Longitudinal Effects in Young Smokers

INTRODUCTION

The present study sought to identify time-dependent within-participant effects of CYP2A6 genotypes on smoking frequency and nicotine dependence in young smokers.

METHODS

Predicted nicotine metabolic rate based on CYP2A6 diplotypes (CYP2A6 diplotype predicted rate [CDPR]) was partitioned into Normal, Intermediate, and Slow categories using a metabolism metric. Growth-curve models characterized baseline and longitudinal CDPR effects with data from eight longitudinal assessments during a 6-year period (from approximately age 16-22) in young smokers of European descent (N = 296, 57% female) who had smoked less than 100 cigarettes lifetime at baseline and more than that amount by Year 6. Phenotypes were number of days smoked during the previous 30 days and a youth version of the Nicotine Dependence Syndrome Scale (NDSS). A zero-inflated Poisson growth-curve model was used to account for the preponderance of zero days smoked.

RESULTS

At baseline, Intermediate CDPR was a risk factor relative to both Normal and Slow CDPR for smoking frequency and the NDSS. Slow CDPR was associated with the highest probability of smoking discontinuation at baseline. However, due to CDPR time trend differences, by young adulthood these baseline effects had been reordered such that the greatest risks for smoking frequency and the NDSS were associated with Normal CDPR.

CONCLUSIONS

Reduced metabolism CYP2A6 genotypes are associated with both risk and protective effects in novice smokers. However, differences in the time-by-CDPR effects result in a reordering of genotype effects such that normal metabolism becomes the risk variant by young adulthood, as has been reliably reported in older smokers.

Nicotine-dependence-varying effects of smoking events on momentary mood changes among adolescents

INTRODUCTION

Theories of nicotine addiction emphasize the initial role of positive reinforcement in the development of regular smoking behavior, and the role of negative reinforcement at later stages. These theories are tested here by examining the effects of amount smoked per smoking event on smoking-related mood changes, and how nicotine dependence (ND) moderates this effect. The current study examines these questions within a sample of light adolescent smokers drawn from the metropolitan Chicago area (N=151, 55.6% female, mean 17.7years).

INSTRUMENTS

Ecological momentary assessment data were collected via handheld computers, and additional variables were drawn from a traditional questionnaire.

METHODS

Effects of the amount smoked per event on changes in positive affect (PA) and negative affect (NA) after vs. before smoking were examined, while controlling for subject-averaged amount smoked, age, gender, and day of week. ND-varying effects were examined using varying effect models to elucidate their change across levels of ND.

RESULTS

The effect of the amount smoked per event was significantly associated with an increase in PA among adolescents with low-to-moderate levels of ND, and was not significant at high ND. Conversely, the effect of the amount smoked was significantly associated with a decrease in NA only for adolescents with low levels of ND.

CONCLUSIONS

These findings support the role of positive reinforcement in early stages of dependent smoking, but do not support the role of negative reinforcement beyond early stages of smoking. Other potential contributing factors to the relationship between smoking behavior and PA/NA change are discussed.

Secondhand smoke exposure and endothelial stress in children and adolescents

OBJECTIVE

Links between secondhand smoke exposure and cardiovascular disease in adults are well established. Little is known about the impact of this exposure on cardiovascular status during childhood. The purpose of this study was to investigate relationships between secondhand smoke exposure in children and adolescents and cardiovascular disease risk--systemic inflammation, endothelial stress, and endothelial repair.

METHODS

A total of 145 subjects, aged 9 to 18 years, were studied. Tobacco smoke exposure was determined by hair nicotine level. Cardiovascular risk was assessed by markers of systemic inflammation (C-reactive protein [CRP] and adiponectin); by soluble intercellular adhesion molecule 1 (s-ICAM1), which measures endothelial activation after surface vascular injury; and by endothelial repair. This was measured by prevalence of endothelial progenitor cells (EPCs), which are bone marrow-derived cells that home preferentially to sites of vascular damage.

RESULTS

Hair nicotine was directly correlated with s-ICAM1 (r = 0.4090, P < .0001) and negatively correlated with EPC prevalence (r = -0.2002, P = .0195). There was no relationship between hair nicotine and CRP, and a trend toward a weak relationship with adiponectin. Hair nicotine and body mass index were independent variables in a multivariate model predicting s-ICAM1; hair nicotine was the only significant variable in a model predicting EPC prevalence.

CONCLUSIONS

Secondhand smoke exposure during childhood and adolescence is detrimental to vascular health because s-ICAM1 is a marker for endothelial activation and stress after vascular surface injury, and EPCs contribute to vascular repair. The fact that body mass index is also a factor in the model predicting s-ICAM1 is concerning, in that 2 risk factors may both contribute to endothelial stress.

Identification of DNA methylation changes in newborns related to maternal smoking during pregnancy

BACKGROUND

Maternal smoking during pregnancy is associated with significant infant morbidity and mortality, and may influence later disease risk. One mechanism by which smoking (and other environmental factors) might have long-lasting effects is through epigenetic modifications such as DNA methylation.

OBJECTIVES

We conducted an epigenome-wide association study (EWAS) investigating alterations in DNA methylation in infants exposed in utero to maternal tobacco smoke, using the Norway Facial Clefts Study.

METHODS

The Illumina HumanMethylation450 BeadChip was used to assess DNA methylation in whole blood from 889 infants shortly after delivery. Of 889 mothers, 287 reported smoking-twice as many smokers as in any previous EWAS of maternal smoking. CpG sites related to maternal smoking during the first trimester were identified using robust linear regression.

RESULTS

We identified 185 CpGs with altered methylation in infants of smokers at genome-wide significance (q-value < 0.05; mean Δβ = ± 2%). These correspond to 110 gene regions, of which 7 have been previously reported and 10 are newly confirmed using publicly available results. Among these 10, the most noteworthy are FRMD4A, ATP9A, GALNT2, and MEG3, implicated in processes related to nicotine dependence, smoking cessation, and placental and embryonic development.

CONCLUSIONS

Our study identified 10 genes with newly established links to maternal smoking. Further, we note differences between smoking-related methylation changes in newborns and adults, suggesting possible distinct effects of direct versus indirect tobacco smoke exposure as well as potential differences due to age. Further work would be needed to determine whether these small changes in DNA methylation are biologically or clinically relevant. The methylation changes identified in newborns may mediate the association between in utero maternal smoking exposure and later health outcomes.

Parental smoking exposure and adolescent smoking trajectories

OBJECTIVE

In a multigenerational study of smoking risk, the objective was to investigate the intergenerational transmission of smoking by examining if exposure to parental smoking and nicotine dependence predicts prospective smoking trajectories among adolescent offspring.

METHODS

Adolescents (n = 406) ages 12 to 17 and a parent completed baseline interviews (2001-2004), and adolescents completed up to 2 follow-up interviews 1 and 5 years later. Baseline interviews gathered detailed information on parental smoking history, including timing and duration, current smoking, and nicotine dependence. Adolescent smoking and nicotine dependence were assessed at each time point. Latent Class Growth Analysis identified prospective smoking trajectory classes from adolescence into young adulthood. Logistic regression was used to examine relationships between parental smoking and adolescent smoking trajectories.

RESULTS

Four adolescent smoking trajectory classes were identified: early regular smokers (6%), early experimenters (23%), late experimenters (41%), and nonsmokers (30%). Adolescents with parents who were nicotine-dependent smokers at baseline were more likely to be early regular smokers (odds ratio 1.18, 95% confidence interval 1.05-1.33) and early experimenters (odds ratio 1.04, 95% confidence interval 1.04-1.25) with each additional year of previous exposure to parental smoking. Parents' current non-nicotine-dependent and former smoking were not associated with adolescent smoking trajectories.

CONCLUSIONS

Exposure to parental nicotine dependence is a critical factor influencing intergenerational transmission of smoking. Adolescents with nicotine-dependent parents are susceptible to more intense smoking patterns and this risk increases with longer duration of exposure. Research is needed to optimize interventions to help nicotine-dependent parents quit smoking early in their children's lifetime to reduce these risks.

Adolescents smoking in the crosslight of other substance use and parental and peers' smoking behaviors

This study investigates the connectedness of adolescents' smoking status, history of alcohol and cannabis use, and parental and peers' smoking, dimensions only rarely explored concurrently. Multinomial regression models that compared the smoking status of adolescents were estimated based on a representative sample of 3,560 adolescents aged 14–15 from Switzerland. While 49.0% of respondents had never smoked, 9.0% smoked on a daily basis and 12.0% occasionally; 32.6% had never drank alcohol and 74.7% had never used cannabis. Overall, parental and peers' smoking and other substance use factors are significantly associated with smoking status. Yet, history of substance use revealed less consistent associations with smoking status among current smokers (daily versus occasional smoking). The findings highlight the connectedness of adolescents' and other substance use behaviors and support the relevance of concurrent prevention initiatives targeting adolescents with specific substance use profiles and/or growing up in prosmoking social milieus.

Alcohol problems as a signal for sensitivity to nicotine dependence and future smoking

BACKGROUND

Alcohol use is a well-documented risk factor for the emergence of chronic smoking behavior. Very little is known, however, about the mediating pathways through which alcohol and/or alcohol-related problems influence future smoking.

METHODS

Data were drawn from the longitudinal Social and Emotional Contexts of Adolescent Smoking Patterns Study (SECASPS). Adolescents who had smoked under 100 cigarettes in their lifetime (n=898; experimenters) and adolescents who had smoked over 100 cigarettes, but fewer than 5 cigarettes per day (n=152: current smokers) were examined separately (grouping variable). Path analysis was performed to investigate the association between alcohol related problems at baseline (primary predictor) and smoking regularity at the 48 month follow-up (primary outcome), both directly and through mediating variables of smoking quantity and frequency, and nicotine dependence (averaged across these measures at 6-, 15-, and 24-month assessment waves).

RESULTS

Among experimenters, after controlling for smoking and alcohol use, the association between alcohol-related problems at baseline and smoking frequency 48 months later was fully mediated by nicotine dependence symptoms. Among current smokers, only past smoking behavior was associated with 48-month smoking frequency.

CONCLUSIONS

Alcohol-related problems are a risk factor for future smoking among novice adolescent smokers above and beyond drinking or smoking per se. By signaling sensitivity to nicotine dependence symptoms, alcohol related problems represent an easily measureable risk factor that can be used to identify and intervene with adolescents before more chronic smoking behaviors emerge.

Exploring alternate processes contributing to the association between maternal smoking and the smoking behavior among young adult offspring

INTRODUCTION

Maternal smoking during pregnancy (MSP) is a known risk factor for regular smoking in young adulthood and may pose a risk independently of mother's lifetime smoking. The processes through which MSP exerts this influence are unknown but may occur through greater smoking quantity and frequency following initiation early in adolescence or increased sensitivity to nicotine dependence (ND) at low levels of smoking.

METHODS

This study used path analysis to investigate adolescent smoking quantity, smoking frequency, and ND as potential simultaneous mediating pathways through which MSP and mother's lifetime smoking (whether she has ever smoked) increase the risk of smoking in young adulthood among experimenters (at baseline, <100 cigarettes/lifetime) and current smokers (>100 cigarettes/lifetime).

RESULTS

For experimenters, MSP was directly associated with more frequent young adult smoking and was not mediated by adolescent smoking behavior or ND. Independently of MSP, the effect of mother's lifetime smoking was fully mediated through frequent smoking and was heightened ND during adolescence. Controlling for MSP eliminated a previously observed direct association between mother's lifetime smoking and future smoking among experimenters. For current smokers, only prior smoking behavior was associated with future smoking frequency.

CONCLUSIONS

These results seem to rule out sensitivity to ND and increased smoking behavior as contributing pathways of MSP. Further, the impact of MSP on young adult smoking extends beyond that of having an ever-smoking mother. Future work should test other possible mediators; for example, MSP-related epigenetic changes or gene variants influencing the brain's nicotine response.