title: Two biochemical markers effectively used to separate smokeless tobacco users from smokers and nonusers.
abstract: Data from asbestos workers were used to devise a cutpoint classifier to identify subjects as Nonuser (non-tobacco user), Smokeless (exclusive smokeless tobacco user), and Smoker (ignited tobacco user). In some clinical trials and smoking cessation programs, Smokeless should be separated from Smoker. One therefore needs a marker for smoke exposure, such as thiocyanate, since nicotine levels, as measured by cotinine, could be similar in both groups. Levels of cotinine (ng/mL) and thiocyanate (mumol/L) levels (mean +/- SD) were, respectively: 320.9 +/- 201.1 and 145.9 +/- 63.7 for the Smoker group; 339.1 +/- 327.5 and 32.0 +/- 16.9 for the Smokeless group; and 0.6 +/- 2.6 and 58.2 +/- 33.2 for the Nonuser group. For Nonuser, Smokeless, and Smoker, respectively, the self-reported status was 45.1%, 10.8%, and 44.1%, which was adjusted to 42.2%, 11.6%, and 46.2%; the classifier yielded sensitivities of 100%, 76.1%, and 92.2%; specificities of 96.1%, 97.6%, and 96.4%; and predictive values of 94.9%, 80.6%, and 95.6%. The classifier successfully identified Nonusers, separated Smokeless from Smoker, and determined the prevalence of false reports in our cohort.
mesh_terms: D000328:Adult; D000368:Aged; D001194:Asbestos; D015331:Cohort Studies; D003367:Cotinine / Q000097:blood*; D016002:Discriminant Analysis; D005260:Female; D005544:Forecasting; D015438:Health Behavior; D006801:Humans; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D010947:Plants, Toxic; D011237:Predictive Value of Tests; D015995:Prevalence; D011336:Probability; D012680:Sensitivity and Specificity; D012907:Smoking / Q000097:blood*; D013861:Thiocyanates / Q000097:blood*; D014030:Tobacco, Smokeless
chemical_list: D013861:Thiocyanates; D001194:Asbestos; D003367:Cotinine; C031760:thiocyanate