Breath Carbon Monoxide and Cotinine as Biomarkers to Distinguish Smokers From Nonsmokers
Condition: Nicotine Dependence
MeSH terms: Tobacco Use Disorder
Study type: Observational

Summary: 
      Background:

        -  Self-report and biochemical verification are used to determine smoking status in
           treatment trials and clinical research. Each method has merits and limitations that make
           it appropriate for particular situations. Participants who feel social pressure to
           report tobacco abstinence may provide unreliable self-reporting results. Biochemical
           verification using breath carbon monoxide (CO) is a more reliable indicator, but several
           biological and environmental factors (including exposure to secondhand smoke) can affect
           the sensitivity and specificity of breath CO measurement.

        -  An ideal biomarker of smoking status is cotinine, the major metabolite of nicotine.
           Cotinine levels found in blood, urine, and saliva can be used to distinguish between
           smokers and nonsmokers, as well as between light and heavy smokers. Researchers are
           interested in using cotinine assessments to develop suitable breath CO cutoff levels to
           categorize different types of smokers and nonsmokers for use in future research.

      Objectives:

      - To determine a breath carbon monoxide (CO) cutoff level that optimally discriminates
      between heavy and light smokers and nonsmokers who are and who are not exposed to
      environmental tobacco smoke.

      Eligibility:

        -  Individuals between 18 and 64 years of age who fall into one of the following groups:

        -  current smokers reporting more than 10 cigarettes per day for at least 6 months

        -  current smokers reporting 10 or fewer cigarettes per day for at least 6 months

        -  nonsmokers reporting regular environmental exposure to tobacco smoke

        -  nonsmokers reporting limited or no exposure to tobacco smoke

      Design:

        -  The study will involve a single outpatient session.

        -  Participants will provide breath CO, urine, and saliva samples, and will complete
           several smoking-related questionnaires on smoking history, current craving levels, and
           perceived level of nicotine dependence.
    

Detailed description: 
      Objective:

      To determine a breath carbon monoxide (CO) cutoff level that optimally discriminates between
      heavy and light smokers and nonsmokers who are and who are not exposed to environmental
      tobacco smoke. Breath CO will be compared against cotinine concentration, which is the gold
      standard in verifying smoking status.

      Study population:

      The study will include four groups: 1) 60 smokers reporting > 10 cigarettes per day, 2) 60
      smokers reporting less than or equal to 10 cigarettes per day, 3) 60 nonsmokers reporting
      regular environmental exposure to tobacco smoke, and 4) 60 nonsmokers reporting limited or no
      environmental exposure to tobacco smoke (total of 120 smokers and 120 nonsmokers).

      Design:

      Parallel groups design.

      Outcome Measures:

      1) breath CO; 2) semiquantitative salivary cotinine; 3) quantitative salivary nicotine,
      cotinine, and 3-hydroxycotinine; 4) semiquantitative urinary cotinine; 5) quantitative
      urinary nicotine, cotinine, norcotinine, and 3-hydroxycotinine; and 6) self-reported smoking
      variables.
    

Time perspective: Other
Keywords: Cigarette Smoking; Biomarkers; Nicotine; Cotinine; Metabolites