Objective: To validate self reports of cigarette and smokeless tobacco (snus) use in a prospective cohort of adolescents. Design: A cross sectional analysis of a cohort sub-sample. Setting: County of Stockholm, Sweden. Subjects: 520 adolescents in the final grade of junior high school (mean age 15.0 years). Main outcome measure: Concordance between self reported tobacco use and saliva cotinine concentration. Results: Using a cut point of 5 ng/ml saliva cotinine to discriminate active tobacco use, there was a 98% concordance between self reported non-use in the past month and cotinine concentration. The sensitivity of the questionnaire compared to the saliva cotinine test, used as the gold standard, was 90% and the specificity 93%. One hundred and fifteen out of 520 subjects (22%) reported monthly tobacco use. Among these, 67% (46/69) of the exclusive cigarette smokers, 82% (23/28) of exclusive snus users, and 94% (15/16) of mixed users (cigarettes + snus) had cotinine concentrations above 5 ng/ml. Among subjects reporting daily use 96% (64/67) had saliva cotinine concentrations above the cut point. Exclusive current cigarette users were more likely to be classified discordantly by questionnaire and cotinine test compared to snus users (odds ratio 3.2, 95% confidence interval 1.2 to 8.6). Conclusion: This study confirms the reliability of adolescents' self reported tobacco use. In a context of low exposure to environmental tobacco smoke a cut off for saliva cotinine of 5 ng/ml reliably discriminated tobacco users from non-users. Irregular use of tobacco in this age group probably explains the discrepancy between self reported use and cotinine concentrations.

Smokeless tobacco users show symptoms of nicotine dependence at least as frequently as cigarette smokers. Symptoms of nicotine dependence and of withdrawal during quit attempts are particularly frequent in the subgroup of users who combine smokeless tobacco with smoking.

School-based recruitment of youth for a research purpose is problematic, as one has to deal with multiple ethical and practical constraints. This study reports on predictors of schools' and families' participation in a longitudinal study of tobacco use among 11-year-old children. School size, but not tobacco policy, was linked to participation. High parental education and average social status in the residence area were associated with parental consent. Given the social background, prevalence of parental tobacco use was close to the expected. Compliance of responsible adults in youth research cannot be predicted on the basis of simple behavioural models.

We employed a variation of the Azrin–Foxx (1971) procedure with a 3.5‐year‐old boy diagnosed with Pervasive Developmental Disability (PDD). Unique features of our design included tailoring to the in‐home environment, training without systematically increasing fluid intake, introduction under circumstances that facilitated generalization and transfer without special procedures, the elimination of some specialized equipment, and use of social and activity reinforcers. Training was successful and was reported to have generalized to the inclusive school environment. Copyright © 2004 John Wiley & Sons, Ltd.

Retrospective reports of smoking in pregnancy are of importance for clinical or scientific purposes. Careful analyses of stability and accuracy of recalled behaviour are, therefore, needed. In 1998, the mothers of 2369 pre-teens born in Sweden retrospectively reported their smoking behaviour during the first trimester of the index pregnancy. We matched these reports with those recorded by midwives at the beginning of the index pregnancy, using information from the Swedish Medical Birth Registry. Using this registry as gold standard, the sensitivity and specificity of the retrospective reports containing any smoking were 83.9% and 92.8% respectively, but the sensitivity was low for daily smoking, 56.0%. Of the 222 discordant reports, 19.0% were due to mothers recalling daily smoking which was not reported at the time of pregnancy, and 42% were due to failure to recall smoking reported at the time of pregnancy, while the remaining 39% retrospectively reported occasional smoking, whereas they were registered as non-daily smokers when pregnant. Retrospective recall of pregnancy smoking is fairly stable over time.