title: Metabolites of a tobacco-specific lung carcinogen in children exposed to secondhand or thirdhand tobacco smoke in their homes.
abstract: BACKGROUND
  People exposed to secondhand tobacco smoke (SHS) inhale the lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) which is metabolized to NNAL and its glucuroniders. These urinary metabolites, termed total NNAL, can be quantified. A related compound, iso-NNAL, has been proposed as a biomarker for exposure to smoke constituent residues on surfaces (thirdhand tobacco smoke). There is limited information in the literature on levels of total NNAL in children exposed to SHS.
  
  
  METHODS
  We recruited 79 parent--child dyads from homes where the enrolled parent was a cigarette smoker and visited their homes. Parents were asked questions, home ambient air quality was evaluated, and children provided urine samples. Urine was analyzed for total NNAL, total cotinine, total nicotine, and iso-NNAL.
  
  
  RESULTS
  Ninety percent of the children had detectable total NNAL in urine; total nicotine and total cotinine were also detected in most samples. There were significant positive relationships between biomarker levels and exposure of children in the home. Levels were highest in homes with no smoking restrictions. African American children had significantly higher levels than other children. iso-NNAL was not detected in any urine sample.
  
  
  CONCLUSIONS
  There was nearly universal exposure of children to the lung carcinogen NNK, due mainly to exposure to SHS from adult smokers in their homes.
  
  
  CONCLUSIONS
  Homes with adult smokers should adopt restrictions to protect their children from exposure to a potent lung carcinogen.
authors.affiliation: Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Janet L
authors.initials: JL
authors.lastname: Thomas
authors.forename: Hongfei
authors.initials: H
authors.lastname: Guo
authors.forename: Steven G
authors.initials: SG
authors.lastname: Carmella
authors.forename: Silvia
authors.initials: S
authors.lastname: Balbo
authors.forename: Shaomei
authors.initials: S
authors.lastname: Han
authors.forename: Andrew
authors.initials: A
authors.lastname: Davis
authors.forename: Andrea
authors.initials: A
authors.lastname: Yoder
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Murphy
authors.forename: Larry C
authors.initials: LC
authors.lastname: An
authors.forename: Jasjit S
authors.initials: JS
authors.lastname: Ahluwalia
authors.forename: Stephen S
authors.initials: SS
authors.lastname: Hecht
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine*; D002273:Carcinogens / Q000378:metabolism*; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D004784:Environmental Monitoring; D005260:Female; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008168:Lung / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D009602:Nitrosamines / Q000378:metabolism* / Q000652:urine*; D011725:Pyridines / Q000652:urine*; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
chemical_list: D015415:Biomarkers; D002273:Carcinogens; D009602:Nitrosamines; D011725:Pyridines; D014028:Tobacco Smoke Pollution; C016583:4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone; C099565:4-(methylnitrosamino)-1-(3-pyridyl)-1-butan-1-ol