title: Nicotine and Toxicant Exposure among U.S. Smokeless Tobacco Users: Results from 1999 to 2012 National Health and Nutrition Examination Survey Data.
abstract: BACKGROUND
  It has been suggested that smokeless tobacco users have high nicotine and toxicant exposure, but studies with nationally representative data have been limited.
  
  
  METHODS
  We analyzed biomarkers of tobacco exposure for 23,684 adult participants from the National Health and Nutrition Examination Survey from 1999 to 2012. The biomarkers analyzed were serum cotinine, urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), blood lead, blood cadmium, blood mercury, urinary arsenic, and urinary N-acetyl-S-(2-cyanoethyl)-L-cysteine. We calculated geometric mean concentrations for each biomarker by tobacco use category and geometric mean ratios adjusting for demographic factors.
  
  
  RESULTS
  Exclusive smokeless tobacco users had higher geometric mean concentrations of serum cotinine [178.9 ng/mL, 95% confidence interval (CI), 145.5-220.0] and NNAL (583.0 pg/mg creatinine, 95% CI, 445.2-763.5) than exclusive cigarette smokers (130.6 ng/mL, 95% CI, 122.3-139.6 and 217.6 pg/mg creatinine, 95% CI, 193.0-245.2, respectively). Smokeless tobacco users also had higher concentrations of blood lead compared with nontobacco users (adjusted geometric mean ratio = 1.30, 95% CI, 1.21-1.38). Based on limited sample sizes, NNAL concentrations for smokeless tobacco users appear to have declined from 2007 to 2008 (geometric mean = 1013.7 pg/mg creatinine, 95% CI, 738.9-1390.8) to 2011 to 2012 (geometric mean = 325.7 pg/mg creatinine, 95% CI, 159.6-664.9).
  
  
  CONCLUSIONS
  Exclusive smokeless tobacco users have higher observed levels of exposure to nicotine and carcinogenic tobacco-specific nitrosamines, as measured by cotinine and NNAL biomarker concentrations, than exclusive cigarette smokers. These patterns in NNAL levels for smokeless tobacco users may be changing over time.
  
  
  CONCLUSIONS
  High exposure to harmful constituents among smokeless tobacco users is a continuing health issue.
authors.affiliation: Office of Science, Center for Tobacco Products, Food and Drug Administration, Silver Spring, Maryland. brian.rostron@fda.hhs.gov.
authors.forename: Brian L
authors.initials: BL
authors.lastname: Rostron
authors.affiliation: Office of Science, Center for Tobacco Products, Food and Drug Administration, Silver Spring, Maryland.
authors.forename: Cindy M
authors.initials: CM
authors.lastname: Chang
authors.affiliation: Office of Science, Center for Tobacco Products, Food and Drug Administration, Silver Spring, Maryland.
authors.forename: Dana M
authors.initials: DM
authors.lastname: van Bemmel
authors.affiliation: Tobacco and Volatiles Branch, Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xia
authors.affiliation: Tobacco and Volatiles Branch, Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Benjamin C
authors.initials: BC
authors.lastname: Blount
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009538:Nicotine / Q000008:administration & dosage* / Q000009:adverse effects; D009749:Nutrition Surveys; D011795:Surveys and Questionnaires; D014030:Tobacco, Smokeless / Q000009:adverse effects / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology
chemical_list: D009538:Nicotine