title: Hair concentrations of nicotine and cotinine in women and their newborn infants.
abstract: BACKGROUND
  To date, no biological markers have been identified that can predict the extent of fetal exposure to the toxic constituents of cigarette smoke. A variety of xenobiotic agents have been shown to accumulate in growing hair.
  
  
  METHODS
  We measured maternal and neonatal hair concentrations of nicotine and cotinine in 94 mother-infant pairs. Mothers who were active smokers, nonsmokers, and passive smokers and their infants were included.
  
  
  RESULTS
  Mothers who were active smokers (n = 36) had mean (SEM) hair concentrations of 19.2 (4.9) ng/mg for nicotine and 6.3 (4.0) ng/mg for cotinine, significantly higher than concentrations in nonsmokers (n = 35) (1.2 [0.4] ng/mg for nicotine and 0.3 [0.06] ng/mg for cotinine, P < .0001). Infants of smokers had mean hair concentrations of 2.4 (0.9) ng/mg for nicotine (range, 0 to 27.3 ng/mg) and 2.8 (0.8) ng/mg for cotinine (range, 0 to 12.2 ng/mg), significantly higher than concentrations in infants of nonsmokers (0.4 [0.09] ng/mg for nicotine and 0.26 [0.04] ng/mg for cotinine, P < .01). Mothers with passive smoke exposure and their infants (n = 23) had significantly higher hair concentrations of nicotine (3.2 [0.8] ng/mg for mothers and 0.28 [0.05] ng/mg for infants) and cotinine (0.9 [0.3] ng/mg for mothers and 0.6 [0.15] ng/mg for infants) than nonsmoking mothers and their infants (P < .01). There was a significant correlation between maternal and neonatal hair concentrations of nicotine (r = .49, P < .001) or cotinine (r = .85, P = .0001).
  
  
  CONCLUSIONS
  This is the first biochemical evidence that infants of passive smokers are at risk of measurable exposure to cigarette smoke. Hair accumulation of cigarette smoke constituents reflects long-term systemic exposure to these toxins and therefore may be well correlated with perinatal risks.
authors.affiliation: Motherisk Program, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Eliopoulos
authors.forename: J
authors.initials: J
authors.lastname: Klein
authors.forename: M K
authors.initials: MK
authors.lastname: Phan
authors.forename: B
authors.initials: B
authors.lastname: Knie
authors.forename: M
authors.initials: M
authors.lastname: Greenwald
authors.forename: D
authors.initials: D
authors.lastname: Chitayat
authors.forename: G
authors.initials: G
authors.lastname: Koren
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis; D003367:Cotinine / Q000032:analysis*; D005260:Female; D006197:Hair / Q000737:chemistry*; D006801:Humans; D007231:Infant, Newborn; D008431:Maternal-Fetal Exchange; D009538:Nicotine / Q000032:analysis*; D011247:Pregnancy; D012907:Smoking / Q000378:metabolism*; D014028:Tobacco Smoke Pollution
chemical_list: D015415:Biomarkers; D014028:Tobacco Smoke Pollution; D009538:Nicotine; D003367:Cotinine