Nicotine-dependence symptoms are associated with smoking frequency in adolescents

Abstract

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.