Relationships Between Smoking Behaviors and Cotinine Levels Among Two American Indian Populations With Distinct Smoking Patterns

Abstract Smoking prevalence, cigarettes per day (CPD), and lung cancer incidence differ between Northern Plains (NP) and Southwestern (SW) American Indian populations. We used cotinine as a biomarker of tobacco smoke exposure to biochemically characterize NP and SW smokers and non-smokers, and to investigate factors associated with variation in tobacco exposure. American Indians (N=636) were recruited from two different tribal populations (NP and SW) as part of a study conducted as part of the Collaborative to Improve Native Cancer Outcomes P50 project. For each participant, a questionnaire assessed smoking status, CPD, secondhand smoke exposure, and traditional ceremonial tobacco use; plasma and/or salivary cotinine was measured. Cotinine levels were (mean ±95% CI) 81.6 ± 14.1 and 21.3 ± 7.3 ng/ml among NP smokers and non-smokers, respectively, and 44.8 ± 14.4 and 9.8 ± 5.8 ng/ml among SW smokers and non-smokers, respectively. Cotinine levels correlated with CPD in both populations (P