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Comparison of Two Means
Published in Marcello Pagano, Kimberlee Gauvreau, Heather Mattie, Principles of Biostatistics, 2022
Marcello Pagano, Kimberlee Gauvreau, Heather Mattie
The data below come from a study that examines the efficacy of saliva cotinine as an indicator for exposure to tobacco smoke. In one part of the study, seven subjects – none of whom were heavy smokers and all of whom had abstained from smoking for at least one week prior to the study – were each required to smoke a single cigarette. Samples of saliva were taken from all individuals 2, 12, 24, and 48 hours after smoking the cigarette. The cotinine levels at 12 hours and at 24 hours are provided below [210]. Assume that cotinine levels are approximately normally distributed.
Tobacco and alcohol use during pregnancy
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Beth A. Bailey, Robert J. Sokol
Given the drawbacks of self-report, determination of pregnancy smoking status in both clinical and research settings often relies on biochemical assessment. Cotinine, a major metabolite of nicotine, is a commonly used biomarker of exposure to tobacco smoke, and cotinine levels in saliva, blood, and urine are often considered the best measure of nicotine consumption (88). Compared with self-report, cotinine levels have been shown to be more accurate indicators of smoking (79) and to be better predictors of pregnancy outcomes (89). Biochemical assessment of smoking behavior is not without limitations, however (83). In addition to the factors of cost and inconvenience, acceptance of appropriately sensitive and specific cutoff points is far from universal. Varying cotinine cutoff levels have been proposed to distinguish smokers from nonsmokers and from those exposed to environmental tobacco smoke (ETS) (90–92). Given varying cut-point recommendations, the use of biochemical assessment may not ever be completely accurate in distinguishing those who smoke, especially intermittently, from those who are only exposed to ETS (93). Thus, using both self-report and biochemical assessment is likely to yield the most accurate information about pregnancy smoking status.
Measurement of Exposure and Dose
Published in Samuel C. Morris, Cancer Risk Assessment, 2020
Smoking is such an important confounding factor in epidemiological studies of environmental carcinogenesis and self-reporting is so often inaccurate (perhaps the product of self-deception on the part of smokers), that a biomarker which can provide a definite and quantitative measure of smoking is highly desirable. Moreover, a marker that could provide a quantitative measure of passive smoking—the involuntary exposure of nearby people to side-stream cigarette smoke—would also be of use. Some nicotine is excreted in the urine; it can be measured in the saliva, also. The rate of nicotine metabolism varies as much as fourfold among smokers, however, so nicotine levels in urine, while specific, do not provide an accurate quantitative indicator unless calibrated in each individual. Levels of cotinine, the major metabolite of nicotine, vary much less than residual nicotine levels; measured in urine, cotinine provides both a specific and relatively accurate quantitative measure of exposure to tobacco smoke. Thiocyanate, a metabolite of hydrogen cyanide (a component of cigarette smoke) has also been suggested as a biomarker for exposure to tobacco smoke; but cyanide is also a component of leafy vegetables, some nuts, and beer, so its metabolite is not specific to cigarette smoke (HHS, 1986).
Association between snus use and lipid status in Swedish men
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2023
Marja Lisa Byhamre, Mats Eliasson, Stefan Söderberg, Patrik Wennberg, Viktor Oskarsson
On each questionnaire (available in Swedish at www.umu.se/forskning/projekt/monica-studien/monica-undersokningen-i-norra-sverige2/), the participants answered to a number of questions related to their current and previous use of snus and cigarettes. In general, the questions on cigarette smoking were more detailed than the questions on snus use (e.g. the questionnaire [i] differentiated between daily and non-daily use of cigarettes but not of snus and [ii] collected information on time since smoking cessation but not on time since snus cessation). To validate the self-reported tobacco habits, plasma concentrations of cotinine (the predominant nicotine metabolite) were measured in a subsample of the 1990 survey (n = 321 subjects; 46.4% men) [21]. Cotinine concentrations were below 12 ng/mL in all non-tobacco users and above 55 ng/mL in almost all tobacco users.
Pharmacological and physiological response in Apoe−/− mice exposed to cigarette smoke or e-cigarette aerosols
Published in Inhalation Toxicology, 2022
Matthew J. Eden, Yasmeen M. Farra, Jacqueline Matz, Chiara Bellini, Jessica M. Oakes
The pharmacokinetics of cotinine depend on the route and type of exposure. In a recent mouse study, Shao et al. (2019) showed that intermittent e-cig (Blu-cig) aerosol exposure resulted in a longer cotinine elimination half-life compared to intraperitoneal injection of nicotine (Petersen et al. 1984). On the other hand, attributed to the protonated form of nicotine, e-cigpods deliver aerosols with a much higher nicotine concentration than the earlier generation e-cigtank devices (Omaiye et al. 2019). E-cigpod vaping elicits similar cotinine pharmacokinetics profiles as cigarette smoking in human users (Hajek et al. 2020), overcoming one of the major limitations of e-cigtank devices (Eissenberg 2010). Furthermore, while not yet fully understood, nicotine salts may cause a different biological action upon inhalation than free-base nicotine (Shao and Friedman 2020).
Exposure to 1,3-Butadiene in the U.S. Population: National Health and Nutrition Examination Survey 2011–2016
Published in Biomarkers, 2021
Alma Nieto, Luyu Zhang, Deepak Bhandari, Wanzhe Zhu, Benjamin C. Blount, Víctor R. De Jesús
Cotinine is a highly specific metabolite of nicotine, the primary addictive chemical in tobacco, and is used as a biomarker of environmental tobacco smoke exposure (Watts et al.1990, Benowitz 1996). In this report, serum cotinine was used as a continuous predictor to evaluate tobacco smoke exposure for both exclusive smokers (N = 726) and non-users (N = 5171). Among non-users, tobacco smoke exposure is attributable to inhalation of SHS, which can be quantified with serum cotinine. In order to assess the association between urinary 1,3-butadiene metabolites and frequency of cigarette smoking, we performed an unstratified, sample-weighted regression model (N = 5897) in which exposure among exclusive smokers was represented by the self-reported average number of cigarettes smoked per day (CPD) over the five days preceding the NHANES physical exam. This CPD regression model comprised the same predictors as the stratified models, except that tobacco smoke exposure was classified in the following mutually exclusive categories: ≤0.015 mg/mL serum cotinine and 0 CPD (unexposed to tobacco smoke), >0.015 – ≤10 mg/mL serum cotinine and 0 CPD (presumptively exposed to SHS), >10 mg/mL serum cotinine and 1–10 CPD, >10 mg/mL serum cotinine and 11–20 CPD, and >10 mg/mL serum cotinine and >20 CPD. The reference category was unexposed participants and was defined at ≤0.015 mg/mL serum cotinine. The analytic dataset for the CPD model and the stratified models comprised the same participants (N = 5897).