Breath Carbon Monoxide and Cotinine as Biomarkers to Distinguish Smokers From Nonsmokers

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.