title: Expired carbon monoxide levels in self-reported smokers and nonsmokers in prison.
abstract: Breath carbon monoxide (CO) is a convenient, widely used method for abstinence validation, with cutoffs of 8-10 ppm commonly employed. The goal of the present study was to determine an appropriate CO cutoff to differentiate nonsmokers and smokers within a large sample (N = 374) of female prisoners incarcerated at a correctional facility in Virginia. Mean age of the population was 34.5 years, 49.2% were White, and 29% had less than a high school education. Smoking prevalence was 74.1% within the prison population. Examination of CO levels versus smoking self-report using a receiver operator characteristic (ROC) analysis revealed that a CO cutoff of 3 ppm resulted in the best sensitivity (98.1%) and specificity (95.8%). Overall ROC area under the curve was 99% (95% CI = 98.2%-99.9%). This same cutoff was optimal for smoking subgroups including Black and light (<10 cigarettes/day) smokers. Results suggest that CO cutoffs higher than 3 ppm may misclassify some smokers as nonsmokers and underestimate the prevalence of smoking.
authors.affiliation: Douglas Wilder School of Government and Public Affairs, Virginia Commonwealth University, Richmond, VA 23284, USA. klcropsey@hsc.vcu.edu
authors.forename: Karen L
authors.initials: KL
authors.lastname: Cropsey
authors.forename: Gloria D
authors.initials: GD
authors.lastname: Eldridge
authors.forename: Michael F
authors.initials: MF
authors.lastname: Weaver
authors.forename: Gabriela C
authors.initials: GC
authors.lastname: Villalobos
authors.forename: Maxine L
authors.initials: ML
authors.lastname: Stitzer
mesh_terms: D000328:Adult; D001944:Breath Tests; D002245:Carbon Dioxide / Q000378:metabolism*; D005260:Female; D006801:Humans; D011237:Predictive Value of Tests; D015995:Prevalence; D011329:Prisoners / Q000706:statistics & numerical data; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012907:Smoking / Q000453:epidemiology*; D016540:Smoking Cessation; D000074606:Smoking Prevention; D014768:Virginia / Q000453:epidemiology
chemical_list: D002245:Carbon Dioxide