Validity of self reports in a cohort of Swedish adolescent smokers and smokeless tobacco (snus) users

Abstract

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.

Impact of Differing Definitions of Dual Tobacco Use: Implications for Studying Dual Use and a Call for Operational Definitions

“…In our review of the literature, prevalence estimates ranged from 6.9% (Bombard et al, 2008) to 19.5% (Everett et al, 2000) in adolescents and from 0.28% (Mumford et al, 2006) to 3.4% (Bombard et al, 2007) in adults in the Unites States. While it appears that prevalence of dual use is higher in adolescents (Bombard et al, 2008;Everett et al, 2000;Gilpin & Pierce, 2003;Horn et al, 2000;Tercyak & Audrain, 2002) and in Sweden (Digard et al, 2009;Galanti et al, 2008;Post et al, 2005Post et al, , 2010Wickholm et al, 2003), direct comparisons of populations is compromised by the lack of a common definition. Our results demonstrate that risk profiles change as the definition of dual use changes.…”

“…We identified 373 articles addressing multiple tobacco product use. Of these, twenty-five articles (Backinger et al, 2008;Bombard, Pederson, Nelson, & Malarcher, 2007;Bombard, Rock, Pederson, & Asman, 2008;Chao et al, 2002;Croucher, Islam, & Pau, 2007;Digard, Errington, Richter, & McAdam, 2009;Everett, Malarcher, Sharp, Husten, & Giovino, 2000;Galanti, Rosendahl, & Wickholm, 2008;Gilpin & Pierce, 2003;Horn, Gao, Dino, & Kamal-Bahl, 2000;Lando, Haddock, Klesges, Talcott, & Jensen, 1999;Mumford, Levy, Gitchell, & Blackman, 2005Post et al, 2005Post et al, , 2010Rigotti, Lee, & Wechsler, 2000;Rodu & Cole, 2009;Rodu, Stegmayr, Nasic, & Asplund, 2002;Skander & Larbaoui, 1989;Spangler et al, 1999Spangler et al, , 2001Tercyak & Audrain, 2002;Tomar, 2002;Wetter et al, 2002;Wickholm, Galanti, Soder, & Gilljam, 2003) reported prevalence data based upon the type and frequency of tobacco use (Supplementary Appendix A). Several different terms were used to describe the simultaneous use of two tobacco products, including "dual use" (Digard et al, 2009;Post et al, 2010;Rodu & Cole, 2009;Spangler et al, 1999Spangler et al, , 2001, "concurrent use" (Croucher et al, 2007;Mumford et al, 2005Mumford et al, , 2006Tomar, 2002), "combined use" (Rodu et al, 2002;Wickholm et al,...…”

“…Most studies (17 of 25) analyzed the use of both cigarettes and ST (Croucher et al, 2007;Digard et al, 2009;Galanti et al, 2008;Horn et al, 2000;Lando et al, 1999;Mumford et al, 2005Mumford et al, , 2006Post et al, 2005Post et al, , 2010Rodu & Cole, 2009;Rodu et al, 2002;Skander & Larbaoui, 1989;Spangler et al, 1999Spangler et al, , 2001Tomar, 2002;Wetter et al, 2002;Wickholm et al, 2003); one study analyzed cigarettes, ST, or cigars (Everett et al, 2000); three studies analyzed cigarettes, ST, cigars, and pipes (Backinger et al, 2008;Chao et al, 2002;Rigotti et al, 2000); one study analyzed cigarettes, ST, cigars, or bidis (Gilpin & Pierce, 2003); one study analyzed cigarettes, ST, cigars, pipe, or bidis (Bombard et al, 2007); and two studies analyzed cigarettes, ST, cigars, pipes, bidis, or kreteks (Bombard et al, 2008;Tercyak & Audrain, 2002). The frequency of use requirement to define current tobacco use also varied substantially.…”

“…The frequency of use requirement to define current tobacco use also varied substantially. In eight studies, current dual use was defined as smoking cigarettes with other tobacco products at any point within the past thirty days, and any number other than zero was considered a current user (Bombard et al, 2008;Everett et al, 2000;Gilpin & Pierce, 2003;Mumford et al, 2005;Post et al, 2005Post et al, , 2010Spangler et al, 2001;Tercyak & Audrain, 2002). Five other studies identified a participant as a current dual user if use of tobacco products was "every day or some days" (Bombard et al, 2007;Horn et al, 2000;Rodu & Cole, 2009;Tomar, 2002;Wickholm et al, 2003).…”

Occasional tobacco use among young adult women: a longitudinal analysis of smoking transitions

“…42 Furthermore, self-reported smoking status was not confirmed with biochemical validation of tobacco consumption. Although a high degree of concordance with self-reported smoking has been found among both adolescents 43 and adults, 44 self-reports of occasional smoking may be more problematic. In a study of long-term and transitional occasional smokers, 4% of baseline occasional smokers reported that they had never smoked at the 1-year follow-up.…”