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The Nicotine Dependence in Teens (NDIT) study is a prospective cohort investigation of 1294 students recruited in 1999-2000 from all grade 7 classes in a convenience sample of 10 high schools in Montreal, Canada. Its primary objectives were to study the natural course and determinants of cigarette smoking and nicotine dependence in novice smokers. The main source of data was self-report questionnaires administered in class at school every 3 months from grade 7 to grade 11 (1999-2005), for a total of 20 survey cycles during high school education. Questionnaires were also completed after graduation from high school in 2007-08 and 2011-12 (survey cycles 21 and 22, respectively) when participants were aged 20 and 24 years on average, respectively. In addition to its primary objectives, NDIT has embedded studies on obesity, blood pressure, physical activity, team sports, sedentary behaviour, diet, genetics, alcohol use, use of illicit drugs, second-hand smoke, gambling, sleep and mental health. Results to date are described in 58 publications, 20 manuscripts in preparation, 13 MSc and PhD theses and 111 conference presentations. Access to NDIT data is open to university-appointed or affiliated investigators and to masters, doctoral and postdoctoral students, through their primary supervisor (www.nditstudy.ca). [ABSTRACT FROM AUTHOR]

Introduction: In addition to individual-level characteristics, the social and physical environment may influence the initiation of cigarette smoking in adolescents. The objective of this paper is to describe the association between smoking intolerance in schools, and in restaurants and corner stores located near schools, and initiation of cigarette smoking among adolescents. Methods: Data on cigarette smoking were collected in self-report questionnaires every 3 months from 1999 to 2005 in a sample of 1,293 Grade 7 students in 10 secondary schools in Montreal, Canada. Baseline never-smokers (n = 868) were retained for analysis. School administrators completed questionnaires on tobacco control policies and activities within schools. Data on access to tobacco products and smoking restrictions in restaurants and corner stores located in school neighborhoods were collected through direct observation. Schools, restaurants, and corner stores were classified as smoking tolerant or intolerant. Time to initiation of cigarette smoking was modeled as a function of smoking intolerance in schools, restaurants, and corner stores in survival analyses (Cox proportional hazards modeling). Results: Students in smoking-intolerant schools were less likely to initiate smoking than students in smoking-tolerant schools (hazard ratio [HR; 95% CI] = 0.83 [0.68, 1.01]). Students attending schools located in neighborhoods with smoking-intolerant restaurants were less likely to initiate smoking (HR [95% CI] = 0.85 [0.68, 1.07]). There was no association between corner store smoking intolerance and initiation. Conclusions: Smoking intolerance in schools and restaurants may protect against initiation of cigarette smoking and could be useful targets for more intense tobacco control efforts. [ABSTRACT FROM AUTHOR]

Although related to inflammatory markers in adults, little is known about the association between cigarette smoking and C-reactive protein (CRP) in adolescent smokers. We examined the association between high-sensitivity CRP (hs-CRP) concentrations and smoking in youth. We used data from a cross-sectional, province-wide survey of a representative sample of youth conducted in Quebec, Canada, in 1999. Data were collected in self-report questionnaires completed by participants and their parents. Participants provided a fasting blood sample, and anthropometric measures were undertaken by trained technicians. The present analysis pertains to 1,501 adolescents aged 13 and 16 years who completed questionnaires and for whom blood samples were available. The independent association between a six-category indicator of smoking status and elevated hs-CRP, defined as a value at least in the 90th percentile of the age- and sex-specific CRP distribution, was assessed in multiple logistic regression analyses controlling for potential confounders. Relative to never-smokers, the odds ratios (95% confidence intervals) for puffers (i.e., never smoked a whole cigarette), those who smoked but not in the past month, light past-month smokers, moderate past-month smokers, and heavy past-month smokers were 1.04 (0.55-1.98), 1.76 (1.06-2.94), 1.39 (0.70-2.76), 2.07 (0.96-4.42), and 2.40 (1.18-4.88), respectively. Our data suggest a positive association between smoking status and elevated CRP in adolescents, and in particular among heavier past-month smokers. Damage related to cigarette smoking may begin soon after tobacco use initiation, reinforcing the preventive message that no level of smoking is safe in youth. [ABSTRACT FROM AUTHOR]