Regular articleDeterminants of salivary cotinine concentrations in Chinese male smokers
Introduction
There are now about 1.1 billion smokers in the world, using diverse tobacco products. Nicotine addiction is central in the maintenance of sustained smoking, but little is known about nicotine delivery and dose in smokers around the world. Measurement of cotinine, the major proximate metabolite of nicotine, in smokers can provide a characterization of nicotine dose received by a population.
Cotinine can be measured in body fluids, such as plasma, saliva, and urine, as a biomarker of inhaled or ingested nicotine [1], [2]. Cotinine is readily detectable in smokers with a distribution of levels quite distinct from that of nonsmokers. Earlier studies have shown different mean salivary and serum concentrations of cotinine among U.S. smokers of different ethnic backgrounds including Hispanics, blacks, and whites [3], [4], [5]. These differences may reflect differences in smoking behavior, types of cigarettes smoked, and/or nicotine metabolism between smokers of different ethnic groups [5], [6], [7], [8], [9]. The roles of smoking behavior and product characteristics in modifying cotinine concentrations are not yet well understood.
Since nicotine is the major addictive substance in cigarette smoke, cotinine levels of body fluids, as an indicator of nicotine dose, may prove to be important predictors of smoking cessation rates. Identification of factors affecting cotinine levels in body fluids may provide useful information for planning of smoking cessation programs, and for determining the appropriate dosage for nicotine replacement therapy. In addition, the intake of nicotine can be taken as a surrogate for exposure to tar and other toxic substances in tobacco smoke and may thus be predictive of the adverse health effects of smoking [9].
In China, the proportion of active smokers is high among men and low among women. In the National Smoking Prevalence Survey conducted in China in 1996, 63% of men and 4% of women were current smokers [10]. The distribution of cotinine levels in the Chinese smoking population has not been studied previously.
The aims of the present study were to characterize the distribution of salivary cotinine levels in Chinese smokers from Beijing and Shanghai, and to investigate factors that influence salivary cotinine levels in smokers. In addition, this study forms the first part of a multicountry study that will compare the relation of the number of cigarettes smoked with salivary cotinine concentration across different national groups, including China, Mexico, and Brazil.
Section snippets
Study design
A cross-sectional study was conducted among adults in Beijing and Shanghai, China, with interviews and saliva specimen collection taking place between January and March 1999. The Human Research Committees of the Johns Hopkins School of Public Health and the Chinese Academy of Preventive Medicine approved the study.
Study population
The study sample included 600 Chinese adult smokers 15 years or older who were residents in the cities of Beijing and Shanghai (300 subjects in each city). Trained interviewers from
Characteristics and salivary cotinine concentrations of the study population
The distribution of individual characteristics, smoking behavior, and tobacco product characteristics are presented in Table 1 for the total population of 600 subjects and for the final study population of 510 subjects, all cigarette-smoking men. The distributions of most of the characteristics were essentially similar in the study population and in the total population. The number of cigarettes smoked daily was slightly higher in the study population. The median number of cigarettes smoked in
Discussion
This study evaluated the relation between the number of cigarettes smoked in the previous 24 hours and salivary cotinine concentration in a sample of Chinese adults from Beijing and Shanghai. Cotinine concentration as a function of the number of cigarettes smoked fitted well a linear model for the purposes of our analyses. However, the best fit to the data was a convex relation with flattening of the change in cotinine at about 20–30 cigarettes. This form of the curve suggests that there is an
Conclusions
In a population of Chinese male smokers, salivary cotinine concentration increased significantly with the number of cigarettes smoked in the previous 24 hours, a quadratic model providing the best fit to the data. Flattening of this relation was observed at 20–30 cigarettes. Among those smoking up to 20 cigarettes, the median cotinine concentration was higher among younger subjects, among those smoking cigarettes without filter and regular cigarettes rather than light cigarettes, among those
Acknowledgements
This study was funded by a grant from SmithKline Beecham Consumer Healthcare to the Institute for Global Tobacco Control at the Johns Hopkins University Bloomberry School of Public Health. The study was initiated and analyzed by the investigators.
References (24)
- et al.
Menthol and nonmenthol cigarettes and smoke exposure in black and white women
Pharmacol Biochem Behav
(1996) A review of use of saliva cotinine as a marker of tobacco smoke exposure
Prev Med
(1990)- et al.
Improved gas chromatographic method for the determination of nicotine and cotinine in biologic fluids
J Chromatogr B Biomed Appl
(1981) - et al.
Analytical cigarette yields as predictors of smoke bioavailability
Regul Toxicol Pharmacol
(1985) - et al.
Tea drinking, passive smoking, smoking deception and serum cotinine in the Scottish heart health study
J Clin Epidemiol
(1991) - et al.
Dietary nicotinea source of urinary cotinine
Food Chem Toxicol
(1991) - et al.
Comparison of tests used to distinguish smokers from nonsmokers
Am J Public Health
(1987) Cotinine as a biomarker of environmental tobacco smoke exposure
Epidemiol Rev
(1996)- et al.
Racial differences in serum cotinine levels among smokers in the Coronary Artery Risk Development in (Young) Adults Study
Am J Public Health
(1990) - et al.
Cigarette yields of tar and nicotine and markers of exposure to tobacco smoke
Am Rev Respir Dis
(1993)
Racial and ethnic differences in serum cotinine levels of cigarette smokers. Third National Health and Nutrition Examination Survey, 1988–1991
JAMA
How a cigarette is smoked determines blood nicotine levels
Clin Pharmacol Ther
Cited by (28)
Mononuclear leukocyte DNA damage and oxidative stress: The association with smoking of hand-rolled and filter-cigarettes
2011, Mutation Research - Genetic Toxicology and Environmental MutagenesisCitation Excerpt :Therefore, this method was suitable for testing the genetic integrity of the mononuclear leukocytes. Nicotine is the major addictive substance in cigarette smoke and the cotinine level in body fluids serves as an indicator of the nicotine dose and is an important marker of smoking behaviour [35]. Therefore, we assessed plasma cotinine levels to determine smoking behaviour.
Assessment of exposure to secondhand smoke by questionnaire and salivary cotinine in the general population of Barcelona, Spain (2004-2005)
2009, Preventive MedicineCitation Excerpt :Participants were asked to rinse their mouths and then suck a lemon candy (Smint®) to stimulate saliva production. They were asked to spit out a small amount of saliva and then to provide about 8 ml of saliva by spitting into a funnel placed in a test tube (Jaakkola et al., 2003; Campuzano et al., 2004; Blackford et al., 2006). The sample was separated into 3 ml aliquots and frozen to − 20 °C for storage.
Passive cigarette smoke exposure in primary school children in Liverpool
2006, Public HealthSimultaneous determination of nicotine, cotinine, norcotinine, and trans-3′-hydroxycotinine in human oral fluid using solid phase extraction and gas chromatography-mass spectrometry
2005, Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences