Garbis Meshefedjian

Nicotine-dependence symptoms are associated with smoking frequency in adolescents

BACKGROUND Although many sociodemographic and psychosocial factors have been identified as related to adolescent smoking, few studies have examined the role of nicotine-dependence (ND) symptoms. The objective was to study the association between ND symptoms and smoking status among adolescents in the early stages of the smoking onset process. METHODS The McGill University Study on the Natural History of Nicotine Dependence is an ongoing 6-year prospective investigation of the natural history of ND among 1267 grade 7 students in ten Montreal high schools. The baseline response was 55.4%. Subjects for this cross-sectional analysis of baseline data, collected in 1999, included 241 past 3-month smokers (mean age [SD]=13.0+/-0.7 years at baseline). ND symptoms were measured in five indicators, including a measure based on the criteria for tobacco dependence in the International Classification of Diseases-10th Revision (ICD-10), the Hooked on Nicotine Checklist, and three symptom clusters (withdrawal, self-medication, and ND/cravings symptoms). The association between ND symptom indicators and each of sporadic, monthly, weekly, and daily smoking relative to less frequent smoking was investigated in multiple logistic regression analysis. RESULTS Despite low cigarette exposure, 16.6% (95% confidence interval [CI], 11.9%-21.3%) of past 3-month smokers were tobacco dependent. The proportion increased from 0%, 3.1% (95% CI, 0.0%-9.2%), and 4.6% (95% CI, 0.2%-9.0%) among triers, sporadic smokers, and monthly smokers, respectively, to 19.4% (95% CI, 5.5%-33.3%) and 65.9% (95% CI, 51.9%-79.9%) among weekly and daily smokers, respectively. ND/cravings consistently distinguished each smoking category from less frequent smokers; the odds ratios (95% CI) for ND/cravings symptoms were 1.16 (0.99-1.35) in sporadic smokers; 1.17 (1.06-1.29) in monthly smokers; 1.34 (1.19-1.50) in weekly smokers; and 1.39 (1.22-1.59) in daily smokers. CONCLUSIONS These data challenge current smoking onset models, which suggest that ND develops only after several years of heavy or daily smoking. ND symptoms are associated, at least cross-sectionally, with increased smoking in adolescents. To increase the likelihood of being effective, tobacco-control programs for children and adolescents will need to take early ND symptoms into account.

Genetically decreased CYP2A6 and the risk of tobacco dependence: a prospective study of novice smokers

Objective: Case control studies in adults suggest that defective alleles in the gene that codes for the hepatic cytochrome P450 2A6 (CYP2A6) protect against nicotine dependence (ND) and higher levels of cigarette consumption. These two hypotheses were tested in young adolescents. Design: Self reports of tobacco use and ND symptoms were collected every 3–4 months in a prospective study of 1293 grade 7 students from a convenience sample of 10 schools. Subjects: 281 smokers with genetic data were analysed; those who were not already tobacco dependent and who had inhaled (n  =  228) were followed 29.9 months on average, until they became dependent or were censored. Main outcome measures: The association between metabolic activity, represented by CYP2A6 genotype, and conversion to dependence was analysed using Cox’s proportional hazards model. Results: During follow up 67 subjects (29.4%) became dependent. Relative to CYP2A6*1/*1, having 1–2 copies of the inactive CYP2A6*2 or *4 variant was a strong risk factor for developing dependence (hazard ratio 2.8, 95% confidence 1.3 to 6.3). Subjects with 1–2 partially inactive CYP2A6*9 or *12 variants were not at increased risk. Mean past-week cigarette consumption at the end of follow up (controlling for age, sex, and number of months since first inhalation) among dependent subjects was 29.1 among normal inactivators, compared to 17.2, and 12.7 among slower (1–2 copies of *9 or *12), and slowest (1–2 copies of *2 or *4) inactivators, respectively (p  =  0.09). Conclusion: Adolescents with 1–2 copies of CYP2A6*2 or *4 are at substantially increased risk of becoming dependent but smoke less once dependent. Genetic risk for ND may need to be considered in the conceptualisation of tobacco control programmes for adolescents.

Prevalence and Correlates of Overweight among Elementary Schoolchildren in Multiethnic, Low Income, Inner-City Neighbourhoods in Montreal, Canada

PURPOSE Increased understanding of the early determinants of obesity is essential because of the increasing prevalence of obesity in many industrialized countries. METHOD As part of the evaluation of a school-based heart health promotion intervention, we measured height, weight, and triceps skinfold thickness at baseline in 2108 students aged 9-12 years (80.5% of eligible students) in 24 inner-city elementary schools located in multiethnic, low income neighbourhoods in Montreal, Canada. Data on students socio-demographic and lifestyle characteristics were collected in classroom-administered questionnaires, and parents completed an at-home self-administered questionnaire. RESULTS Overall, 35.2% of boys and 33.0% of girls were overweight (> or = 85th age and gender-specific percentiles from NHANES 11, for body mass index and triceps skinfold thickness); 15.1% of boys and 13.3% of girls were obese (> or = 95th age and gender-specific percentiles for body mass index and triceps skinfold thickness). Younger age, having lived all ones life in Canada, and being of European or Central American/Caribbean family origin were independent correlates of obesity in boys. Younger age, ever smoked, mother obese and father obese were independent correlates of obesity in girls. Girls of Asian family origin were protected. CONCLUSIONS The very high prevalence of overweight students in this low income, multiethnic population suggests an important need for preventive intervention.

Milestones in the Process of Cessation Among Novice Adolescent Smokers

OBJECTIVES We sought to document the sequence and timing of milestones in the process of smoking cessation by prospectively studied cessation milestones among novice adolescent smokers. METHODS Participants, aged 12 to 13 years in 1999 (n = 1293), completed self-report questionnaires every 3 months during the school year over 5 years. We ascertained time after first puff to attain 5 cessation milestones among 319 participants who initiated cigarette smoking during follow-up. RESULTS The cumulative probability of first reports of a serious desire to quit and perceived permanent cessation was 25% at 1.5 months (95% confidence interval [CI] = 1.5, 2.5) after the first puff. The first serious quit attempt occurred at 2.5 months (95% CI = 2.5, 5.4), lack of confidence about quitting followed at 18.4 months (95% CI = 18.4, 26.8), and awareness of the difficulty of quitting occurred at 32.2 months (95% CI = 19.2, 38.4). CONCLUSIONS Desire and attempts to quit began soon after smoking onset. Novice smokers progressed through several stages in their perception of the difficulty of quitting. Increased understanding of the cessation process may help in developing effective tobacco control interventions for novice smokers.

Prevalence and Correlates of Early Smoking among Elementary Schoolchildren in Multiethnic, Low-Income Inner-City Neighborhoods

PURPOSE The prevalence and correlates of early smoking were investigated among schoolchildren in grades 4-6 living in multiethnic, low-income neighborhoods in Montreal. METHODS As part of the evaluation of a school-based heart health promotion program, baseline data on the prevalence of early smoking were collected from 2285 students aged 9-13 years in 24 inner-city elementary schools during May-June 1993. RESULTS Overall, 28.7% of boys and 20.3% of girls had smoked. Girls began trying later than boys, but by age 13 the prevalence of experimental or regular smoking by girls overtook that of boys. Univariately, ever smoking varied considerably by family origin, from 2.1% among Vietnamese girls, to 35.8% among Portuguese boys. In multivariate analysis, age, perceived smoking habits of friends, and smoking by family members, were strong correlates of smoking. Being of Asian family origin was negatively associated with smoking. None of the indicators of social class were significantly associated with ever smoking. CONCLUSIONS Smoking prevention should begin with children even younger than age 9 in multiethnic, low-income, inner-city neighborhoods. With the exception of a lower prevalence of smoking among Asian children, ethnicity and social class were not strong influences on early smoking behavior in this population.

The “Yes, I Quit” Smoking Cessation Course: Does it Help Women in a Low Income Community Quit?

The objectives were to evaluate the impact of “Yes, I Quit” (a smoking cessation course tailored for women in a low income, low education community), and to identify baseline predictors of short and longer-term self-reported cessation. The impact was evaluated in a before-after study design with no comparison group. Baseline data were collected in self-administered questionnaires at the beginning of the first session of the course. Follow-up data were collected in telephone interviews at one, three and six months after the designated Quit Day. Self-reported quit rates among 122 participants were 31.1%, 24.7% and 22.3% at one, three and six months. Non-quitters reduced their consumption by 10.3, 8.3, and 7.1 cigarettes per day at one, three and six months. Multivariate logistic regression analyses showed that being in excellent/good health was significantly associated with cessation at one month (odds ratio (OR) = 2.4). Being married (OR = 13.0) and no other smokers in the household (OR = 3.6) were associated with three-month cessation. Only being married was associated with six-month cessation (OR = 6.8). “Yes, I Quit” produced quit rates among low income, low education participants comparable to those reported for cessation programs directed at the general population of smokers. Good health is associated with early cessation, while support from a spouse is important to maintaining a nonsmoking status among quitters.

Distinguishing risk factors for the onset of cravings, withdrawal symptoms and tolerance in novice adolescent smokers

Aim: While many studies report determinants of adolescent cigarette smoking, few identify risk factors for nicotine dependence (ND). This study distinguished between risk factors for three hallmarks of ND including cravings, withdrawal symptoms and tolerance. Methods: A total of 319 novice smokers were followed every 3 months from first puff on a cigarette until the end of secondary school. Outcomes included time to first report of cravings, withdrawal symptoms and tolerance. Results: Female sex, inhalation, smoking a whole cigarette, weekly smoking, daily smoking and alcohol use each independently increased the incidence of the onset of cravings. Inhalation, weekly smoking, daily smoking and alcohol use predicted the onset of withdrawal symptoms. Withdrawal symptoms, smoking a whole cigarette, monthly smoking, daily smoking and friends and siblings smoking increased the incidence of the onset of tolerance. None of parental education, impulsivity, novelty seeking, self-esteem, depression, stress, parental smoking, physical activity, or participation in sports teams was associated with the outcomes. Conclusion: The hallmarks of early ND are related to intensity and frequency of cigarette use. Avoidance of daily smoking may be particularly important in preventing the onset of ND symptoms and sustained smoking.