The importance of timing of transitions for risk of regular smoking and nicotine dependence

Time to first report of signs of nicotine dependence among youth who use e-cigarettes and cigarettes in the United States: A nationally representative cohort study, findings from the Population Assessment of Tobacco and Health, 2013-2019

OBJECTIVE

To determine the time to first report of signs of nicotine dependence among youth exclusive e-cigarette users and compare this time to that for exclusive cigarette users.

METHODS

Secondary analysis of data (Waves 1-5; 2013-2019) from the Population Assessment of Tobacco and Health was conducted. Youth never tobacco users in the United States who reported exclusive past-30-day (P30D) e-cigarette or cigarette use (n = 2940, N = 5,391,642) in at least one wave were included in the current analysis. Survival analysis was used to estimate the time to the first report of three nicotine dependence indicators (i.e., "use within 30 minutes of waking"; "cravings" and "really needing to use") following the first report of P30D use. Multivariable Cox proportional hazard models were used to estimate adjusted hazard ratios (aHR).

RESULTS

There were no significant differences in the time to first report of "use within 30 minutes of waking" (aHR = 1.1, 95% CI = 0.87-1.40) and "cravings" (aHR = 1.09, 95% CI = 0.81-1.47) between exclusive P30D e-cigarette use and exclusive P30D cigarette use. However, compared to exclusive P30D e-cigarette use, the hazard of first reporting "really needing to use" tobacco was 39% (aHR 1.39; 95% CI: 1.05-1.84) times higher for those who reported exclusive P30D cigarette use after controlling for covariates.

CONCLUSION

Compared to exclusive P30D cigarette use, no differences in the time to first report of signs of nicotine dependence ("use within 30 minutes" and "cravings") were observed among exclusive P30D e-cigarette users. Policymakers and regulatory agencies should consider this evidence when assessing the abuse liability of e-cigarette products.

Selection of eligible participants for screening for lung cancer using primary care data

Lung cancer screening is effective if offered to people at increased risk of the disease. Currently, direct contact with potential participants is required for evaluating risk. A way to reduce the number of ineligible people contacted might be to apply risk-prediction models directly to digital primary care data, but model performance in this setting is unknown.

METHOD

The Clinical Practice Research Datalink, a computerised, longitudinal primary care database, was used to evaluate the Liverpool Lung Project V.2 (LLP_v2) and Prostate Lung Colorectal and Ovarian (modified 2012) (PLCO_m2012) models. Lung cancer occurrence over 5-6 years was measured in ever-smokers aged 50-80 years and compared with 5-year (LLP_v2) and 6-year (PLCO_m2012) predicted risk.

RESULTS

Over 5 and 6 years, 7123 and 7876 lung cancers occurred, respectively, from a cohort of 842 109 ever-smokers. After recalibration, LLP_V2 produced a c-statistic of 0.700 (0.694-0.710), but mean predicted risk was over-estimated (predicted: 4.61%, actual: 0.9%). PLCO_m2012 showed similar performance (c-statistic: 0.679 (0.673-0.685), predicted risk: 3.76%. Applying risk-thresholds of 1% (LLP_v2) and 0.15% (PLCO_m2012), would avoid contacting 42.7% and 27.4% of ever-smokers who did not develop lung cancer for screening eligibility assessment, at the cost of missing 15.6% and 11.4% of lung cancers.

CONCLUSION

Risk-prediction models showed only moderate discrimination when applied to routinely collected primary care data, which may be explained by quality and completeness of data. However, they may substantially reduce the number of people for initial evaluation of screening eligibility, at the cost of missing some lung cancers. Further work is needed to establish whether newer models have improved performance in primary care data.

Increasing socioeconomic disparities in tobacco smoking decline among French adolescents (2000-2017)

BACKGROUND

This paper studies the evolution of transitions from first cigarette use to daily use by socioeconomic status (SES) among French adolescents over the course of 17 years, in a context of decreasing prevalence of tobacco use.

METHODS

A total of 182 266 adolescents participated in the nationally representative ESCAPAD survey at nine different time points between 2000 and 2017. Discrete time-event analysis was used to model the transition to daily cigarette use as a function of SES, gender, age at onset and the use of other psychoactive substances.

RESULTS

Although lifetime cigarette smoking and daily cigarette smoking decreased significantly over the studied time span, suggesting a positive impact of prevention policies, disadvantaged adolescents were consistently more prone to engage in daily cigarette smoking, more so in 2017 than 15 years earlier. In the same time span, transitions from initiation to daily cigarette smoking have shortened, with an accelerated pace among underprivileged adolescents.

CONCLUSIONS

Accelerated transitions from initiation to daily cigarette use are a prevalent trend among disadvantaged adolescents in France. Efforts to mitigate the impact of marketing strategies and to promote health literacy should be pursued to reduce social inequalities in health.

Cigarette smoking as a risk factor for schizophrenia or all non-affective psychoses

BACKGROUND

Smoking tobacco is regarded as an epiphenomenon in patients with schizophrenia when it may be causal. We aimed to examine whether smoking status is related to the onset of schizophrenia or the broader diagnosis of non-affective psychosis, including schizophrenia.

METHODS

We used data from The Health Improvement Network primary care database to identify people aged 15-24 between 1 January 2004 and 31 December 2009. We followed them until the earliest of: first diagnosis of schizophrenia (or psychosis), patient left the practice, practice left THIN, patient died or 31 December 2014.

RESULTS

In men, incidence rates for schizophrenia per 100 000 person years at risk were higher in smoking initiators (non-smoker who became a smoker during the study) than in non-smokers (adjusted IRR 1.94; 95% CI 1.29-2.91) and higher still in smokers (adjusted IRR 3.32; 95% CI 2.67-4.14). Among women, the incidence rate of schizophrenia was higher in smokers than in non-smokers (adjusted IRR 1.50; 95% CI 1.06-2.12), but no higher in smoking initiators than non-smokers. For non-affective psychosis, the pattern was similar for men but more evident in women where psychosis incidence rates were higher in smoking initiators (adjusted IRR 1.90; 95% CI 1.40-2.56) and in smokers (adjusted IRR 2.13; 95% CI 1.76-2.57) than in non-smokers.

CONCLUSIONS

We found an important and strong association between smoking and incidence of schizophrenia. Smoking may increase risk through as yet unknown pathways or smoking may share genetic risk with schizophrenia and non-affective psychoses.

Smoking in Young Adults: A Study of 4-Year Smoking Behavior Patterns and Residential Presence of Features Facilitating Smoking Using Data From the Interdisciplinary Study of Inequalities in Smoking Cohort

INTRODUCTION

Young adults have the highest prevalence of smoking among all age groups in most industrialized countries and exhibit great variability in smoking behavior. Differences in associations between features in residential environments and smoking initiation, prevalence, and cessation have been extensively examined in the literature. Nonetheless, in many cases, findings remain inconsistent. This paper proposes that a potential driver of these inconsistencies is an almost exclusive focus on point-specific smoking outcomes, without consideration for the different behavior patterns that this age group may experience over time.

AIMS AND METHODS

Based on data from the Interdisciplinary Study of Inequalities in Smoking cohort of 18- to 25-year-old Montreal residents (n = 1025), we examined associations between 4-year smoking patterns measured at three timepoints and proximal presence/density of tobacco retail outlets and presence of smoker accommodation facilities in Montreal, Canada. Associations were tested using two-level multinomial and logistic models.

RESULTS

In fully adjusted models, compared to never-smokers, residents of areas with a higher density of tobacco retail were more likely to (1) be characterized as established smokers, (2) have experienced repeated changes in smoking status (being "switchers") during the 4-year study period, and (3) be former smokers.

CONCLUSIONS

From a conceptual standpoint, these findings highlight the importance of acknowledging and examining smoking behavior patterns among young adults. Furthermore, specific pattern-feature associations may point to unique mechanisms by which features could influence smoking behavior patterns. These findings require replication and extension, including testing hypotheses regarding tobacco retail density's role in sustaining smoking and in influencing changes in smoking status.

IMPLICATIONS

Results from this study highlight the importance of describing and examining different young adult smoking behavior patterns and how they may be influenced by residential environment features such as the density of tobacco retail. Findings suggest that young adults residing in areas with a higher density of tobacco retailers are more likely to have experienced repeated changes in smoking status and to be established smokers. Further research in this area is needed to advance knowledge of the putative mechanisms by which residential features may influence smoking behavior patterns and to ultimately orient policy and interventions seeking to curb smoking at the local level.

'Time to first tobacco cigarette soon after waking' occurs more often among underage newly incident smokers in the United States, 2004-2017

AIMS

Time to first cigarette (TTFC) after waking is a highly regarded and readily measured manifestation of a tobacco dependence process. We aim to estimate short TTFC as it occurs very soon after the onset of cigarette smoking (CS) in a community sample of newly incident smokers, all 12-21 years of age, and to study risk variation with the age of CS onset.

METHODS

United States National Surveys on Drug Use and Health, 2004-2017, drew large nationally representative samples of 12-to-21-year-old community residents, and used computerized self-interviews to measure tobacco cigarette smoking, the Fagerstrom TTFC construct, and related variables. A 'short' TTFC was defined as smoking the first cigarette after waking up within 30 min vs. 'long' TTFC or smoking more than 30 min. We studied 8188 newly incident smokers, all assessed within six months after the first puff. Estimated age-specific cumulative incidence proportions (CIP) and odds ratios (OR) are estimated and compared, with due attention to complex survey design and weights.

RESULTS

Among underage newly incident smokers (12-17 years old), an estimated 5.2% experienced short TTFC within 6 months after CS onset (95% CI = 4.4%, 6.2%), versus 3.7% for older new smokers (18-21 years; 95% CI = 2.8%, 4.6%). Underage smokers are 1.5 times more likely to develop short TTFC compared to older initiates (95% CI = 1.1, 2.1). No male-female variations are seen, but exploratory analysis disclosed findings that involve Census-defined race-ethnicity subgroups. Non-Hispanic African-American initiates are twice as likely to develop short TTFC, and Hispanic initiates are less likely to develop short TTFC, as compared with non-Hispanic White smokers.

CONCLUSIONS

Based on US community samples our study offers new evidence about TTFC formation observed within six months after the first puff when cigarette smoking starts before age 18 years.

Assessment of an electronic and clinician-delivered brief intervention on cigarette, alcohol and illicit drug use among women in a reproductive healthcare clinic

BACKGROUND

Women are at highest risk for development of a substance use disorder during their reproductive years. We recently evaluated the efficacy of an electronic screening, brief intervention and referral to treatment (e-SBIRT) and a clinician-delivered SBIRT (SBIRT) compared with enhanced usual care (EUC) for reducing overall substance use among women recruited from reproductive health clinics. The present study assessed the impact of the SBIRT interventions within three primary substance subgroups: cigarettes, illicit drugs, and alcohol.

METHODS

This is a secondary analysis from a 3-group randomized trial comparing e-SBIRT and SBIRT to EUC. For the present study, participants (N = 439) were grouped according to their primary substance: cigarettes, alcohol, or illicit drugs. Differences in days per month of primary substance use over time between treatment groups were examined using generalized estimating equations, modelling linear as well as quadratic effects of time.

RESULTS

Cigarettes were the most frequently reported primary substance (n = 251), followed by illicit drugs (n = 137) and alcohol (n = 51). For primary cigarette use the interaction between the linear effect of time and treatment was significant for SBIRT (β (SE) = -0.067 (0.029), p = .020), but not e-SBIRT, suggesting greater reductions in cigarette use over the first 3 months following treatment with SBIRT compared to EUC. However, the significant interaction of SBIRT with time-squared (β (SE) = 0.009 (0.004), p = .049) showed that reductions in cigarette use attenuated over time, such that after month 3, monthly reductions in cigarette use were similar between groups. Results followed a similar pattern for primary illicit drug use among the e-SBIRT group in which the interaction of e-SBIRT treatment with linear time (β (SE) = -0.181 (0.085), p = .033) and quadratic time (β (SE) = 0.028 (0.012), p = .018) were statistically significant suggesting greater reductions in illicit drug use with e-SBIRT versus EUC, which attenuated with time. Neither SBIRT nor e-SBIRT was associated with a significant reduction in days of alcohol use per month, as compared to EUC.

CONCLUSIONS

Reproductive-age women appear to respond differently to electronic- and clinician-delivered interventions, depending on their primary substance. SBIRT reduced use of cigarettes, and e-SBIRT reduced illicit drug use. Although neither intervention reduced primary alcohol use, the sample size was small (n = 51), suggesting a need for further testing in a larger sample.

Age of initiation and transition times to tobacco dependence: Early onset and rapid escalated use increase risk for dependence severity

BACKGROUND

Research indicates that early tobacco initiation increases risk for dependence, but despite this, early initiation is associated with slower transitions to escalated tobacco use. In contrast to these findings, other studies suggest that rapid escalated tobacco use is associated with increased dependence outcomes.

METHODS

Our sample was comprised of 5668 twins (2834 twin-pairs, mean age: 26.89, s.d = 4.42, 53.67% female, 57.69% monozygotic) from Colorado and Minnesota twin cohorts. We assessed the associations between 1) age of tobacco initiation and the speed of transitions (latency) to tobacco problem use and dependence and the associations between 2) age of initiation and latencies to tobacco problem use and dependence with tobacco dependence symptom severity. To further understand the etiological unfolding of these processes, we conducted univariate twin models and causally informative co-twin control models.

RESULTS

After adjustment for covariates, we found that early tobacco initiation was associated with a slower transition from initiation to problem use but a faster transition from problem use to dependence. Additionally, we found that earlier initiation and faster transitions to tobacco problem use and dependence predicted greater tobacco dependence severity within twin pairs (consistent with causal influences). The contribution of shared genetic and environmental factors was also evident for these relationships.

CONCLUSIONS

Our study further disentangles the role of early initiation with transition times to tobacco problem use and dependence. In addition to common risk factors, we found potential causal roles for early tobacco initiation and rapid escalated tobacco use with increased risk for tobacco dependence severity.

Prospective cohort study of childhood behaviour problems and adolescent sexual risk-taking: gender matters

Background Externalising (delinquent, aggressive) and internalising (anxious/depressed, withdrawn) behaviour problems are prevalent in childhood. Few studies have prospectively measured relationships between childhood behaviour problems and adolescent health risk behaviour, a major predictor of morbidity and mortality. This study sought to determine relationships, by gender, between childhood behaviour problems and adolescent risky sexual behaviours and substance use.

METHODS

In a population-based birth cohort [The Western Australian Pregnancy Cohort (Raine) Study], total, externalising and internalising behaviour problems (domain-specific T≥60) were calculated from parent-reported Child Behavior Checklist at ages 2, 5, 8, 10 and 14 years. At age 17 years, 1200 (49% male) participants reported sexual and substance use activity Results: For both genders, those with earlier externalising behaviour problems were more likely to be sexually active (oral sex or sexual intercourse) by age 17 years. Males with childhood externalising behaviour problems were more likely to have multiple sexual partners by age 17 years than those without such problems [adjusted odds ratio (aOR) 2.96, 95% confidence interval (CI) 1.49-5.86]. Females with childhood externalising behaviour problems were more likely to have had unwanted sex (aOR 1.91, 95% CI 1.04-3.53). Externalising behaviour problems were associated with substance use for both genders. No association was found between internalising behaviour problems and risky behaviour.

CONCLUSIONS

Externalising behaviour problems from as early as 5 years old in boys and 8 years old in girls predict a range of risky sexual behaviour in adolescence, which has important implications for targeting interventions in adolescence.

Prevalence and correlates of adolescents' e-cigarette use frequency and dependence

BACKGROUND

Understanding predictors of e-cigarette use among adolescents in the context of wide availability and extreme popularity of these products is important for prevention and treatment. This study identifies correlates of e-cigarette use frequency and dependence among adolescent users.

METHODS

Adolescent e-cigarette users (N = 173) were recruited from the San Francisco Bay Area. Participants reported demographic and psychosocial characteristics, e-cigarette use behaviors, and cigarette use. Bivariate relationships between potential correlates were examined, and correlates significant at p < .10 were included in full models predicting frequency and dependence.

RESULTS

In the full models, frequent use was associated with receiving one's first e-cigarette from a family member rather than a friend (r = -0.23, p < .001) or a store ( = -0.13, p = .037), using nicotine in all e-cigarettes versus some e-cigarettes (r = -0.17, p = .007) or unknown nicotine use (r = -0.15, p = .014), using a customizable device versus a Juul (r = -0.22, p < .001), vape pen (r = -0.20, p = .002), or other/unknown device (r = -0.16, p = .009), and friends' e-cigarette use (r = 0.20, p = .002). Dependence was associated with younger age of first use (r = -0.18, p = .012), friends' use (r = 0.18, p = .01), and recent cigarette use (r = 0.17, p = .019).

CONCLUSIONS

When assessing problematic e-cigarette use among adolescents, it is important to consider social factors (e.g., friends' and family members' e-cigarette use), device type, and dual use with cigarettes.

Development of a Just-in-Time Adaptive Intervention for Smoking Cessation Among Korean American Emerging Adults

PURPOSE

Cigarette smoking is a preventable risk factor that contributes to unnecessary lung cancer burden among Korean Americans and there is limited research on effective smoking cessation strategies for this population. Smartphone-based smoking cessation apps that leverage just-in-time adaptive interventions (JITAIs) hold promise for smokers attempting to quit. However, little is known about how to develop and tailor a smoking cessation JITAI for Korean American emerging adult (KAEA) smokers.

METHOD

This paper documents the development process of MyQuit USC according to design guidelines for JITAI. Our development process builds on findings from a prior ecological momentary assessment study by using qualitative research methods. Semi-structured interviews and a focus group were conducted to inform which intervention options to offer and the decision rules that dictate their delivery.

RESULTS

Qualitative findings highlighted that (1) smoking episodes are highly context-driven and that (2) KAEA smokers believe they need personalized cessation strategies tailored to different contexts. Thus, MyQuit USC operates via decision rules that guide the delivery of personalized implementation intentions, which are contingent on dynamic factors, to be delivered "just in time" at user-scheduled, high-risk smoking situations.

CONCLUSION

Through an iterative design process, informed by quantitative and qualitative formative research, we developed a smoking cessation JITAI tailored specifically for KAEA smokers. Further testing is under way to optimize future versions of the app with the most effective intervention strategies and decision rules. MyQuit USC has the potential to provide cessation support in real-world settings, when KAEAs need them the most.

Tobacco smoking: Health impact, prevalence, correlates and interventions

BACKGROUND AND OBJECTIVES

Despite reductions in prevalence in recent years, tobacco smoking remains one of the main preventable causes of ill-health and premature death worldwide. This paper reviews the extent and nature of harms caused by smoking, the benefits of stopping, patterns of smoking, psychological, pharmacological and social factors that contribute to uptake and maintenance of smoking, the effectiveness of population and individual level interventions aimed at combatting tobacco smoking, and the effectiveness of methods used to reduce the harm caused by continued use of tobacco or nicotine in some form.

RESULTS AND CONCLUSIONS

Smoking behaviour is maintained primarily by the positive and negative reinforcing properties of nicotine delivered rapidly in a way that is affordable and palatable, with the negative health consequences mostly being sufficiently uncertain and distant in time not to create sufficient immediate concern to deter the behaviour. Raising immediate concerns about smoking by tax increases, social marketing and brief advice from health professionals can increase the rate at which smokers try to stop. Providing behavioural and pharmacological support can improve the rate at which those quit attempts succeed. Implementing national programmes containing these components are effective in reducing tobacco smoking prevalence and reducing smoking-related death and disease.

Association of Lifetime Mental Disorders and Subsequent Alcohol and Illicit Drug Use: Results From the National Comorbidity Survey-Adolescent Supplement

OBJECTIVE

To estimate the association of prior lifetime mental disorders with transitions across stages of substance use in a cross-sectional, nationally representative sample of US adolescents.

METHOD

The sample includes 10,123 adolescents aged 13 to 18 years who participated in the National Comorbidity Survey-Adolescent Supplement (NCS-A), and who were directly interviewed with the Composite International Diagnostic Interview (CIDI) Version 3.0 that generates criteria for DSM-IV disorders.

RESULTS

Adolescents with prior lifetime mental disorders had high rates of both alcohol (10.3%) and illicit drug (14.9%) abuse, with or without dependence. Alcohol and drug abuse were highest among adolescents with prior anxiety disorders (17.3% and 20%, respectively) and behavior disorders (15.6% and 24%, respectively). Any prior disorder significantly increased the risk of transition from nonuse to first use, and from use to problematic use of either alcohol or illicit drugs. Multivariate models attenuated the magnitude of the risk of transition associated with each disorder, although prior weekly smoking and illicit drug use demonstrated significant risks of transitions across the 3 stages of alcohol or drug use, as did behavior disorders.

CONCLUSION

The findings provide the first evidence from a nationally representative sample that prior mental disorders represent risk factors for the transition from nonuse to use, and the progression to drug- and alcohol-related problems. Treatment of primary mental disorders is likely to be an important target for the prevention of secondary substance use disorders in youth.

Beyond Smoking Prevalence: Exploring the Variability of Associations between Neighborhood Exposures across Two Nested Spatial Units and Two-Year Smoking Trajectory among Young Adults

Young adults have the highest prevalence of smoking amongst all age groups. Significant uptake occurs after high school age. Although neighborhood exposures have been found to be associated with smoking behavior, research on neighborhood exposures and the smoking trajectories among young adults, and on the role of geographic scale in shaping findings, is scarce. We examined associations between neighborhood exposures across two nested, increasingly large spatial units and smoking trajectory over two years among young adults living in Montreal, Canada. A sample of 2093 participants aged 18-25 years from the Interdisciplinary Study of Inequalities in Smoking (ISIS) was surveyed. The dependent variable was self-reported smoking trajectory over the course of two years. Residential addresses, data on presence of tobacco retail outlets, and the presence of smoking accommodation facilities were coded and linked to spatial units. Three-level multinomial models were used to examine associations. The likelihood of being a smoker for 2+ years was significantly greater among those living in larger spatial unit neighborhoods that had a greater presence of smoking accommodation. This association was not statistically significant at the smaller spatial units. Our findings highlight the importance of studying young adults' smoking trajectories in addition to static smoking outcomes, and point to the relevance of considering spatial scale in studies of neighborhoods and smoking.

New methods shed light on age of onset as a risk factor for nicotine dependence

INTRODUCTION

Early onset of substance use is a risk factor for later drug use, abuse, and dependence. This study examines how the rate of nicotine dependence differs as a function of age of onset of regular smoking in continuous time, in order to identify critical age periods that are most predictive of later dependence for males and females.

METHODS

Time-varying effect modeling (TVEM) can reveal specific ages of onset that confer greatest risk for adult nicotine dependence. The rate of dependence in adulthood is modeled as a flexible function of age of onset using a subset of adults (N = 15,748) from the National Epidemiologic Survey on Alcohol and Related Conditions who ever smoked regularly.

RESULTS

The peak risk of adult nicotine dependence coincides with onset of regular use at approximately 10 years old, with an elevated risk persisting to 20 years. The risk of dependence is significantly higher for females compared to males for onset of regular use between ages 9 and 18.

CONCLUSIONS

Results suggest that the risk of adult nicotine dependence is highest when onset of regular smoking occurs at around 10 years, though the associated risk is high for ages of onset into young adulthood. Early onset of regular use is a relatively stronger risk factor for adolescent females than males. Smoking prevention programs should focus on late childhood through early adolescence, particularly among females. TVEM provides a more nuanced understanding of the risk associated with different ages of onset of health risk behaviors.

The association between peer, parental influence and tobacco product features and earlier age of onset of regular smoking among adults in 27 European countries

BACKGROUND

Factors that influence smoking initiation and age of smoking onset are important considerations in tobacco control. We evaluated European Union (EU)-wide differences in the age of onset of regular smoking, and the potential role of peer, parental and tobacco product design features on the earlier onset of regular smoking among adults <40 years old in 27 EU countries.

METHODS

We analysed data from 4442 current and former smokers aged 15-39 years, collected for the Eurobarometer 77.1 survey (2012). Respondents reported their age at regular smoking onset and factors that influenced their decision to start smoking, including peer influence, parental influence and features of tobacco products. Multi-variable logistic regression, adjusted for age; geographic region; education; difficulty to pay bills; and gender, was used to assess the role of the various pro-tobacco influences on early onset of regular smoking (i.e. <18 years).

RESULTS

Among ever smokers, the mean age of onset of regular smoking was 16.6 years, ranging from 15.8 to 18.8 years in member countries. 68.1% responded that they started smoking regularly when they were <18 years old. Ever smokers who reported they were influenced by peers (OR = 1.70; 95%CI 1.30-2.20) or parents (OR = 1.60; 95%CI 1.21-2.12) were more likely to have started smoking regularly <18 years old. No significant association between design and marketing features of tobacco products and an early initiation of regular smoking was observed (OR = 1.04; 95%CI 0.83-1.31).

CONCLUSIONS

We identified major differences in smoking initiation patterns among EU countries, which may warrant different approaches in the prevention of tobacco use.

Neural correlates of performance monitoring in daily and intermittent smokers

OBJECTIVES

Despite efforts that have increased smoking regulation, cigarette taxation, and social stigma, cigarette smoking remains the leading cause of preventable death worldwide, and a significant personal and public economic burden. In the U.S., intermittent smokers comprise approximately 22% of all smokers and represent a stable, non-dependent group that may possess protective factors that prevent the transition to dependence. One possibility is that intermittent smokers have intact CNS frontal regulatory and control mechanisms that enable resistance to nicotine-induced changes.

METHODS

The present study measured inhibitory control using a flanker task and a go-nogo continuous performance tasks in daily dependent smokers, intermittent non-dependent smokers, and nonsmokers. Event-related potential (ERP) measures of were concurrently recorded to measure performance monitoring via Event-Related Negativity (ERN) and error positivity (Pe) components during error trials for each task.

RESULTS

In both tasks, behavioral and ERN measures did not differ between groups; however, amplitude of the Pe component was largest among intermittent smokers.

CONCLUSIONS

Thus, intermittent smokers differed from both daily smokers and nonsmokers on error processing, potentially revealing neuroprotective cognitive processes in nicotine dependence.

SIGNIFICANCE

A better understanding of factors that mediate behavioral regulation may provide novel treatment approaches that help individuals achieve controlled smoking or cessation.

Long-term effects of laws governing youth access to tobacco

OBJECTIVES

We sought to examine the association between policies governing access to tobacco during adolescence and subsequent adult smoking.

METHODS

We analyzed adult smoking data from the 1998 through 2006-2007 administrations of the US Current Population Survey Tobacco Use Supplement by employing a quasi experimental approach. Participants (n = 105,519) were adults, aged 18 to 34 years at the time of the survey. Smoking outcomes included having ever smoked 100 cigarettes, smoking at the time of the survey, and having smoked 10 or more cigarettes a day conditioned on being an ever smoker. These were predicted from exposure to state youth access policies at age 17 years.

RESULTS

Four of the 9 policies exhibited significant associations with reduced prevalence of 1 or more smoking outcomes, primarily among women. Lesser effects for other policies could not be ruled out.

CONCLUSIONS

Restrictions on youth access to tobacco might lead to reduction in smoking prevalence later in adulthood. The effect might be limited to women; we estimate that having all policies in place could be associated with a 14% reduction in lifetime smoking prevalence for women, and an additional 29% reduction in heavy smoking among ever smokers.

Transitions to regular smoking and nicotine dependence in the Adolescent National Comorbidity Survey (NCS-A)

OBJECTIVE

This study aims to investigate the occurrence of nicotine dependence following the achievement of previous smoking milestones (initiation, weekly, and daily smoking).

METHOD

Analyses are based on data from The National Comorbidity Survey-Adolescent, a nationally representative face-to-face survey of 10,123 adolescents (age 13-17) conducted between 2001 and 2004.

RESULTS

Among adolescents who had ever smoked (36.0%), 40.7% reached weekly smoking levels and 32.8% had reached daily smoking. Approximately one in five adolescents who had ever smoked (19.6%) met criteria for nicotine dependence. An earlier age of smoking initiation, a shorter time since the onset of smoking and faster transitions among smoking milestones were independently associated with the onset of daily smoking and nicotine dependence.

CONCLUSIONS

These findings shed new light on the course of smoking and nicotine dependence during adolescence by demonstrating a rapid transition across smoking stages for those most at risk for the development of chronic and dependent use.

Differences in time to onset of smoking and nicotine dependence by race/ethnicity in a Midwestern sample of adolescents and young adults from a high risk family study

OBJECTIVE

The objective of this study was to determine whether race/ethnicity was associated with time to smoking initiation and time from first cigarette to onset of DSM-IV nicotine dependence (ND) after adjusting for familial and individual psychosocial risk factors.

METHODS

Cox proportional hazards models with time-dependent covariates were used to analyze data from 1376 offspring aged 12-33 years from 532 families at high risk for substance use problems due to paternal alcohol problems and 235 low risk families. Fifty-six percent of the sample self-identified as African-American (AA) and 44% were mainly of European descent.

RESULTS

Controlling for covariates, AAs began smoking at older ages (HR=0.58; 95% CI: 0.48-0.70) and had longer times between smoking initiation and onset of ND compared to non-AAs (HR=0.25, 95% CI: 0.16-0.39 for ND onset occurring <18 years and HR=0.49, 95% CI: 0.30-0.80 for ND onsets ≥ age 18). After additionally controlling for number of cigarettes smoked daily, the racial/ethnic effects for onset of ND were attenuated, but remained statistically significant for ND onset <18 (HR=0.34, 95% CI: 0.19-0.61); however, the estimate was no longer significant for later ND onset (HR=0.84, 95% CI: 0.50-1.41).

CONCLUSIONS

AA adolescents and young adults initiate smoking at older ages and have longer transition periods between initiation and onset of ND compared to non-AAs, even after controlling for many relevant psychiatric and psychosocial covariates; however, racial/ethnic differences in time to onset of nicotine dependence in late adolescence and young adulthood may be explained by differences in daily quantity smoked.

Genetics of smoking and depression

Smoking and depression are significant public health problems with multiple etiological dimensions and outcomes. Although each condition is important by itself, they are important because they often potentiate each other. Consequently, it is also essential to understand the nature their relationship. This representative review focuses on the genetic etiology of the relationship in the context of reviewing first the epidemiology of depression and smoking, and then by exploring behavioral and molecular genetic studies, and other psychiatric and medical comorbidities. At this point, epidemiological evidence for a relationship between depression and smoking/nicotine dependence is compelling. Although behavioral genetic results differ somewhat by gender and in accordance with specific definitions of depression and smoking variables, recent studies show converging evidence for common genetic factors underlying the relationship, often in addition to non-shared environmental factors. The search for underlying genes and genetic mechanisms is at an early stage, but shows promising candidate genes and genetic approaches for future studies.

Genetics of schizophrenia and smoking: an approach to studying their comorbidity based on epidemiological findings

The association between schizophrenia and tobacco smoking has been described in more than 1,000 articles, many with inadequate methodology. The studies on this association can focus on: (1) current smoking, ever smoking or smoking cessation; (2) non-psychiatric controls or controls with severe mental illness (e.g., bipolar disorder); and (3) higher smoking frequency or greater usage in smokers. The association with the most potential for genetic studies is that between ever daily smoking and schizophrenia; it may reflect a shared genetic vulnerability. To reduce the number of false-positive genes, we propose a three-stage approach derived from epidemiological knowledge. In the first stage, only genetic variations associated with ever daily smoking that are simultaneously significant within the non-psychiatric controls, the bipolar disorder controls and the schizophrenia cases will be selected. Only those genetic variations that are simultaneously significant in the three hypothesis tests will be tested in the second stage, where the prevalence of the genes must be significantly higher in schizophrenia than in bipolar disorder, and significantly higher in bipolar disorder than in controls. The genes simultaneously significant in the second stage will be included in a third stage where the gene variations must be significantly more frequent in schizophrenia patients who did not start smoking daily until their 20s (late start) versus those who had an early start. Any genetic approach to psychiatric disorders may fail if attention is not given to comorbidity and epidemiological studies that suggest which comorbidities are likely to be explained by genetics and which are not. Our approach, which examines the results of epidemiological studies on comorbidities and then looks for genes that simultaneously satisfy epidemiologically suggested sets of hypotheses, may also apply to the study of other major illnesses.

Flaws of drug instrumentalization

The adaptive use of drugs, or “drug instrumentalization,” is presented as a reality that the scientific literature has largely ignored. In this commentary, we demonstrate why this concept has limited value from the standpoint of nosology, why it should not be viewed as “adaptive,” and why it has dangerous implications for policy and public health efforts.

Development and reliability of the lifetime interview on smoking trajectories

INTRODUCTION

Assessments of lifetime smoking history are useful in many types of research including surveillance, epidemiology, prevention, intervention, and studies of genetic phenotypes and heritability. Because prospective assessment is impractical for most research, our objective was to develop a reliable retrospective measure of lifetime smoking history. This paper presents descriptive and test-retest reliability data on smoking history variables assessed using the Lifetime Interview on Smoking Trajectories (LIST).

METHODS

Data were collected on a birth cohort sample of 1,625 men and women (ages 34-44) from the Collaborative Perinatal Project. A subsample of 344 was invited to participate in a retest interview 4-8 weeks later and 220 participated. Indices of test-retest reliability were evaluated for smoking history variables, including: (a) early smoking experiences; (b) age at various smoking milestones, such as first puff, and progression to weekly and daily smoking; (c) smoking rate and time to first cigarette within initial, current, most recent, and heaviest phases; and (d) prolonged nonsmoking phases.

RESULTS

Responses to whether each of 5 major smoking milestones occurred were all highly reliable (κ = .78-.92), and of the 20 phase-specific variables assessed, more than half were reported at the highest level of reliability. None of the variables demonstrated low reliability.

CONCLUSIONS

Although retrospective reports have unavoidable limitations, our findings indicate that the LIST is a reliable instrument for assessing detailed retrospective smoking history data and can be used to add to the knowledge base of how patterns of use relate to a variety of outcomes of interest.

Longitudinal evaluation of a smoking prevention program for adolescents

OBJECTIVE

To evaluate a smoking prevention program for adolescents.

METHODS

The program was conducted between 1999 and 2002, in schools of the district of Lisbon, Portugal. The program integrated activities in the school, family and community. This was a longitudinal quasi-experimental study, based on Community Intervention Trial, with randomly defined control conditions (CC) and intervention conditions (IC). A total of four questionnaires were applied in the beginning of the 7th(T1), 8th(T2) and 9th(T3) and in the end of the 9th(T4) school grades, to 1,205 adolescents, aged 13 years on average, of which 57% were girls and 55% were included in the IC. Exposure to prevention activities, psychosocial determinants of smoking and behavior were the variables considered in the evaluation of the program. Variance analysis and logistic regression were used to test the differences between the two study conditions.

RESULTS

IC obtained better results in the smoking psychosocial determinants and in behavior. At the end of the project, 41.8% of participants in the IC and 53.3% of those in the CC had tried tobacco (OR = 0.62; CI95% 0.49;0.80), while those who became regular smokers totaled 8.0% and 12.4%, respectively (OR = 0.59; CI95% 0.40;0.87).

CONCLUSIONS

The program reduced the initiation of smoking and regular smoking. Results appeared in the second year and improved in the third. Effectiveness of smoking prevention programs depends on a continuous implementation throughout adolescence and on the integration of measures aimed to reach adolescents directly and indirectly through their social context (school, family and community).

Probability and predictors of transition from first use to dependence on nicotine, alcohol, cannabis, and cocaine: results of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC)

BACKGROUND

This study aims to estimate general and racial-ethnic specific cumulative probability of developing dependence among nicotine, alcohol, cannabis or cocaine users, and to identify predictors of transition to substance dependence.

METHODS

Analyses were done for the subsample of lifetime nicotine (n=15,918), alcohol (n=28,907), cannabis (n=7389) or cocaine (n=2259) users who participated in the first and second wave of the National Epidemiological Survey on Alcohol and Related Conditions (NESARC). Discrete-time survival analyses were implemented to estimate the cumulative probability of transitioning from use to dependence and to identify predictors of transition to dependence.

RESULTS

The cumulative probability estimate of transition to dependence was 67.5% for nicotine users, 22.7% for alcohol users, 20.9% for cocaine users, and 8.9% for cannabis users. Half of the cases of dependence on nicotine, alcohol, cannabis and cocaine were observed approximately 27, 13, 5 and 4 years after use onset, respectively. Significant racial-ethnic differences were observed in the probability of transition to dependence across the four substances. Several predictors of dependence were common across the four substances assessed.

CONCLUSIONS

Transition from use to dependence was highest for nicotine users, followed by cocaine, alcohol and cannabis users. Transition to cannabis or cocaine dependence occurred faster than transition to nicotine or alcohol dependence. The existence of common predictors of transition dependence across substances suggests that shared mechanisms are involved. The increased risk of transition to dependence among individuals from minorities or those with psychiatric or dependence comorbidity highlights the importance of promoting outreach and treatment of these populations.

Body mass index and regular smoking in young adult women

Little is known about the relationship between relative body weight and transition from experimentation to regular smoking in young adult women. In the current study, data from 2494 participants in wave 4 of the Missouri Adolescent Female Twin Study (aged 18-29years) who reported ever smoking a cigarette were analyzed using logistic regression. Body mass index (BMI) at time of interview was categorized according to CDC adult guidelines, and regular smoking was defined as having ever smoked 100 or more cigarettes and having smoked at least once a week for two months in a row. Since the OR's for the overweight and obese groups did not differ significantly from one another in any model tested, these groups were combined. Forty-five percent of women who had ever smoked had become regular smokers. Testing of interactions between potential covariates and levels of the categorical BMI variable revealed a significant interaction between overweight/obesity and childhood sexual abuse (CSA; p<0.001) associated with regular smoking. Among women reporting CSA, the association between overweight/obesity and having become a regular smoker was negative (n=374; OR=0.48, 95% CI: 0.28-0.81). Both underweight and overweight/obesity were positively associated with transition to regular smoking among women who did not report CSA (n=2076; OR=1.57, 95% CI: 1.05-2.35 and OR=1.73, 95% CI: 1.35-2.20, respectively). These results suggest that experiencing CSA alters the association between BMI and regular smoking in women who have experimented with cigarettes.

Mental disorders as risk factors for substance use, abuse and dependence: results from the 10-year follow-up of the National Comorbidity Survey

AIMS

The comorbidity of mental disorders and substance dependence is well documented, but prospective investigations in community samples are rare. This investigation examines the role of primary mental disorders as risk factors for the later onset of nicotine, alcohol and illicit drug use, abuse and dependence with abuse.

DESIGN

The National Comorbidity Survey (NCS) was a nationally representative survey of mental and substance disorders in the United States carried out in 1990-92. The NCS-2 re-interviewed a probability subsample of NCS respondents in 2001-03, a decade after the baseline survey.

PARTICIPANTS

A total of 5001 NCS respondents were re-interviewed in the NCS-2 (87.6% of baseline sample).

RESULTS

Aggregate analyses demonstrated significant prospective risks posed by baseline mental disorders for the onset of nicotine, alcohol and illicit drug dependence with abuse over the follow-up period. Particularly strong and consistent associations were observed for behavioral disorders and previous substance use conditions, as well as for certain mood and anxiety disorders. Conditional analyses demonstrated that many observed associations were limited to specific categories of use, abuse or dependence, including several mental disorders that were non-significant predictors in the aggregate analyses.

CONCLUSIONS

Many mental disorders are associated with an increased risk of later substance use conditions, but important differences in these associations are observed across the categories of use, abuse and dependence with abuse. These prospective findings have implications for the precision of prevention and treatment strategies targeting substance use disorders.

Single versus recurrent depression history: differentiating risk factors among current US smokers

INTRODUCTION

The strong relationship between persistent tobacco use and Major Depressive Disorder (MDD) has motivated clinical trials of specialized treatments targeting smokers with a history of MDD. Meta-analyses suggest positive responses to specialized treatments have been observed consistently among smokers with history of recurrent rather than a single episode of MDD. Approximately 15% of current US smokers have a history of recurrent MDD. Little is known about the risk factors that contribute to persistent smoking and differentiate these at-risk smokers, US.

METHODS

The National Comorbidity Survey - Replication (NCS-R) included a survey of 1560 smokers participants aged 18 and older in the United States. Lifetime history of MDD was categorized according to chronicity: no history (No MDD), single episode (MDD-S) and recurrent depression (MDD-R). The relationship between the chronicity of MDD, smoking characteristics, cessation history, nicotine dependence, comorbidity with psychiatric disorders, and current functional impairments were examined.

RESULTS

MDD-R smokers reported fewer lifetime cessation efforts, smoked more cigarettes, had higher levels of nicotine dependence, had higher rates of comorbid psychiatric disorders and greater functional impairment than smokers with No MDD. MDD-S smokers were not consistently distinguished from No MDD smokers on cessation attempts, level of daily smoking, nicotine dependence or functional impairment indices.

CONCLUSIONS

The study highlights the importance of chronicity when characterizing depression-related risk of persistent smoking behavior. Although, clinical trials suggest MDD-R smokers specifically benefit from specialized behavioral treatments, these services are not widely available and more efforts are needed to engage MDD-R smokers in efficacious treatments.

Early emerging nicotine-dependence symptoms: a signal of propensity for chronic smoking behavior in adolescents

OBJECTIVE

To evaluate the predictive validity of nicotine-dependence symptoms in 9th- and 10th-grade adolescents.

STUDY DESIGN

A total of 594 adolescents who had not smoked more than 100 cigarettes in their lifetime and 152 adolescents who had smoked more than 100 cigarettes in their lifetime were included in the analysis. The predictive validity of 10 nicotine-dependence items administered at baseline was evaluated at the 24-month follow-up assessment.

RESULTS

For those who smoked fewer than 100 cigarettes, higher levels of experienced nicotine-dependence symptoms at baseline, as well as individual symptoms, predicted current and daily smoking behavior at the 24-month follow-up, over and above baseline smoking. For adolescents who had smoked more than 100 cigarettes at baseline, the level of nicotine dependence and individual symptom endorsement did not predict smoking behavior at the 24-month follow-up.

CONCLUSIONS

Our findings demonstrate that early emerging dependence symptoms reported at low levels of smoking exposure signal a greater propensity for continued smoking behavior not accounted for by current or past smoking exposure. Screening for these early emerging symptoms among novice adolescent smokers represents an important and unused tool in tobacco control efforts aimed at preventing the development of chronic smoking patterns.

Adult versus adolescent onset of smoking: how are mood disorders and other risk factors involved?

AIMS

To examine the strength of association between smoking and mood disorders and the association between smoking and its traditional risk factors, comparing those who started smoking in adolescence with those who started smoking in early adulthood.

DESIGN AND PARTICIPANTS

The analyses relied on prospective data from the Zurich Study. This longitudinal community study started in 1979 with a stratified sample of 591 participants aged 20/21 years, weighted towards those with mental disorders. Follow-up interviews were conducted at ages 23, 28, 30, 35 and 41.

MEASUREMENTS

In this analysis the adult versus adolescent onset of smoking was regressed on the cumulative prevalence of mood disorders, personality characteristics measured by the Freiburg Personality Inventory, common risk factors such as parental smoking, conduct and school problems, troubles with the family and basic socio-demographic variables (sex, education).

FINDINGS

In the Zurich Study cohort we found that 61.6% were former or current smokers, of whom 87% started smoking before the age of 20 and 13% after the age of 20. Adolescent onset of smoking was associated strongly with later major depression, dysthymia or bipolar disorders and, furthermore, with parental smoking, extroverted personality and discipline problems and rebelliousness in youth. However, only depression and dysthymia were associated with adult onset smoking and other risk factors associated with smoking were not so associated in this group.

CONCLUSIONS

Correlates of smoking onset in adolescence are mainly not applicable to the onset of smoking in young adulthood. Smoking onset beyond adolescence is an open research issue.