chap3.1janvier13:Layout 1 13/01/2009 09:55 Page 75 3.1 Measuring tobacco use behaviours Introduction semination of tobacco-related Natural history of tobacco use surveillance data.” The majority of tobacco control In addition, Section 1-d of Article The natural history of tobacco use is policies are designed to reduce 21 requires each ratifying nation to often conceptualized as a series of tobacco use or exposure to tobacco provide periodic updates on sur- steps that can progress from never smoke in the environment; stra- veillance and research as specified use, to trial, experimentation, estab- tegies that are clearly supported by in Article 20. Article 22 calls for lished use, attempting to quit, the scientific literature (US cooperation among the Parties to relapse, and/or maintenance of Department of Health and Human promote the transfer of technical cessation (Figure 3.1 and Table 3.1) Services, 2004, 2006; IARC, 2004, and scientific expertise on sur- (US Department of Health and 2007a). Preventing initiation and veillance and evaluation, among Human Services, 1990, 1994; promoting quitting are the two major other topics (WHO, 2003). Marcus et al. , 1993; Pierce et al ., tobacco control strategies designed This section will first review the 1998b; Mayhew et al., 2000; Choi et to reduce use. To facilitate pro- natural history of tobacco use (e.g. al. , 2001; Hughes et al ., 2003). Prior gress, article 20 of the WHO initiation, current use, cessation). In to actual initiation of use, never Framework Convention on Tobacco epidemiologic studies of disease users often think about use, a step Control (FCTC) calls for Parties to: etiology, such as those discussed in in the process that is described in IARC Monographs (e.g. IARC 2004) Section 3.2. After initial trial, users “(a) establish progressively a national and reports of the Surgeon General can either continue to experiment or system for the epidemiological (US Department of Health and discontinue and become former surveillance of tobacco con- Human Services, 2004), tobacco use triers. Experimenters can either sumption and related social, behaviours (e.g. number of years progress to established user or economic and health indicators smoked, number of cigarettes con- discontinue use and become former (b) cooperate with competent inter- sumed each day) serve as inde- experimenters. Recent research national and regional inter- pendent variables. In the evaluation suggests that nicotine dependence governmental organizations and of the tobacco policies discussed in may appear during the experi- other bodies, including govern- this Handbook, tobacco use mentation phase, before use mental and nongovernmental behaviours serve as dependent becomes established (DiFranza et agencies, in regional and global variables. The section will then al., 2002a; O’Loughlin et al., 2003; tobacco surveillance and ex- discuss factors that can influence the Fidler et al., 2006). Use becomes change of information on the validity of self-report and factors that established when a threshold of indicators specified in para- can influence comparability across cumulative lifetime exposure is graph 3(a) of this Article surveys. The section will end by surpassed. The exact threshold of (c) cooperate with the World Health describing several measures to established use is unknown and Organization in the develop- assess use, providing examples likely varies considerably, but is ment of general guidelines or from cross-national surveillance and often considered as having smoked procedures for defining the evaluation systems (Section 4.3), as at least 100 lifetime cigarettes, or collection, analysis and dis- well as national sources. being exposed to a similar amount 75 chap3.1janvier13:Layout 1 13/01/2009 09:55 Page 76 IARC Handbooks of Cancer Prevention Never user Trier Former trier Experimenter Former experimenter Transition to established use (100 cigarettes) Non daily user Daily user Quit attempt Former user Note: “Use” involves consumption of cigarettes, other forms of smoked tobacco products, and/or various smokeless tobacco products. Figure 3.1 The natural history of tobacco use 76 chap3.1janvier13:Layout 1 13/01/2009 09:55 Page 77 Measuring tobacco use behaviours I. Initiation a. Intention to try (Section 3.2) b. Initial trial i. Discontinuation after initial trial c. Experimentation i. Discontinuation of experimentation II. Transition to established use a. Ever daily versus never-daily III. Current use a. Frequency of use (daily versus non-daily) b. Type of product used c. Brand used d. Intensity of use (units/day) e. Topography (for smoked products) f. Purchase patterns (partly covered in Section 5.1) IV. Cessation a. Intention to quit (Section 3.2) b. Quit attempt i. Intentionality 1. Planned 2. Spontaneous ii. Dose management 1. Abrupt discontinuance 2. Gradual reduction iii. Methods (Section 5.7) 1. Assisted 2. Unassisted c. Maintenance of abstinence versus return to use †Here the term “use” means consumption of cigarettes, other forms of smoked tobacco products, and/or various forms of smokeless tobacco Table 3.1 The Natural History of Tobacco Use†: Key Constructs of other tobacco products. Estab- Services, 1990; Gilpin & Pierce, Validity of self-report of cur- lished use is generally manifested 1994; Hughes et al., 2003; West, rent tobacco use behaviours as daily use. However, persistent, 2006). Quit attempts can be regular non-daily use can also planned or spontaneous, involve Survey-based measures of cur- take place (Evans et al., 1992; abrupt discontinuance or gradual rent tobacco use behaviours, Husten et al., 1998; Trosclair et reduction in use before quitting, assessed in samples that are al., 2005). Once past the threshold and may or may not be assisted representative of a given popu- of established use, discontinuance by one or more of several lation, allow researchers and involves an attempt to quit, with available treatment strategies policy-makers to estimate patterns the outcome of each quit attempt (Fiore et al. , 1990; Giovino et al., of and trends in use overall and for being either relapse or main- 1993; West, et al ., 2001). subgroups in the population. tenance of cessation (US Depart- National prevalence estimates ment of Health and Human have, in the vast majority of cases, 77 chap3.1janvier13:Layout 1 13/01/2009 09:55 Page 78 IARC Handbooks of Cancer Prevention been based on self-reports of Saliva is the biological fluid of natively, some actual non-users of personal behaviours. Self-report, choice in population-based sur- a product (e.g. cigarettes) may be however, may be subject to veys, because it is the easiest to exposed to extremely high doses misclassification bias. Survey res- obtain. Hair nicotine levels reflect of secondhand smoke, or they pondents can either state that they exposure over a longer period of may use other tobacco products do not currently use tobacco, time (Al-Delaimy, 2002). Hair or nicotine replacement therapy, when in fact they do (mis- samples are even easier to obtain and thus may test positive for classification of use as non-use), than saliva. However, measure- cotinine. Exposure to secondhand or that they do currently use ment of nicotine in hair can be smoke, and use of other tobacco tobacco when, in fact they do not influenced by hair color, treatment, products that are available in a (misclassification of non-use as and growth rate and identifying given nation, should be deter- use). Each of these misclassi- nicotine from actual tobacco use mined by questionnaire assess- fication biases can compromise versus exposure to environmental ment and accounted for in validity the validity of a survey estimate. sources can be problematic (Al- assessments. In addition, cotinine Delaimy, 2002) . levels may be influenced by Determining validity: Unfortunately, the use of racial/ethnic differences in the rate biomarkers as indicators of actual of nicotine metabolism and intake Validation of self-report is generally use is also subject to error. of nicotine per cigarette smoked conducted using biomarkers of Studies using cotinine to validate (Caraballo et al ., 1998; Perez- exposure to tobacco or tobacco self-report must determine a cut- Stable et al ., 1998; Benowitz et al. , smoke as criteria. Biomarkers of off for discriminating users from 2002), suggesting that different exposure that have been used in non-users. Cut-offs generally cut-offs may be needed for studies include nicotine; cotinine, a range from 10.0-20.0 ng/ml for different racial/ethnic groups. major metabolite of nicotine; car- serum or saliva cotinine among Furthermore, the cut-off for bon monoxide; and thiocyanate adults (Pirkle et al., 1996; Cara- pregnant women is lower (e.g. 10 (Society for Research on Nicotine ballo et al ., 2001, 2004; Society for ng/ml) than for the general adult and Tobacco, 2002; Al-Delaimy, Research on Nicotine and Tobac- population (Rebagliato et al., 2002). Nicotine and cotinine are co, 2002) and 5.0-11.4 ng/ml 1998; Owen & McNeil, 2001; almost exclusively specific to saliva or serum for adolescents Society for Research on Nicotine tobacco products. Very low levels (McNeill et al ., 1987; Caraballo et and Tobacco, 2002). of nicotine can be found in some al. , 2004; Post et al ., 2005). Self-reports from studies with a vegetables, but their impact on Optimally, a cut-off is selected in a high demand for abstinence can cotinine levels is insignificant manner that results in the highest be biased (Velicer et al. , 1992; (Pirkle et al., 1996; Society for