title: Age- and concentration-dependent elimination half-life of 2,3,7,8-tetrachlorodibenzo-p-dioxin in Seveso children.
abstract: OBJECTIVE
  Pharmacokinetic and statistical analyses are reported to elucidate key variables affecting 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) elimination in children and adolescents.
  
  
  METHODS
  We used blood concentrations to calculate TCDD elimination half-life. Variables examined by statistical analysis include age, latency from exposure, sex, TCDD concentration and quantity in the body, severity of chloracne response, body mass index, and body fat mass.
  
  
  METHODS
  Blood was collected from 1976 to 1993 from residents of Seveso, Italy, who were < 18 years of age at the time of a nearby trichlorophenol reactor explosion in July 1976.
  
  
  RESULTS
  TCDD half-life in persons < 18 years of age averaged 1.6 years while those > or =18 years of age averaged 3.2 years. Half-life is strongly associated with age, showing a cohort average increase of 0.12 year half-life per year of age or time since exposure. A significant concentration-dependency is also identified, showing shorter half-lives for TCDD concentrations > 400 ppt for children < 12 years of age and 700 ppt when including adults. Moderate correlations are also observed between half-life and body mass index, body fat mass, TCDD mass, and chloracne response.
  
  
  CONCLUSIONS
  Children and adolescents have shorter TCDD half-lives and a slower rate of increase in half-life than adults, and this effect is augmented at higher body burdens.
  
  
  CONCLUSIONS
  Modeling of TCDD blood concentrations or body burden in humans should take into account the markedly shorter elimination half-life observed in children and adolescents and concentration-dependent effects observed in persons > 400-700 ppt.
authors.affiliation: Health Science Resource Integration, Tallahassee, Florida, USA. brentkerger@att.net
authors.forename: Brent D
authors.initials: BD
authors.lastname: Kerger
authors.forename: Hon-Wing
authors.initials: HW
authors.lastname: Leung
authors.forename: Paul
authors.initials: P
authors.lastname: Scott
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Paustenbach
authors.forename: Larry L
authors.initials: LL
authors.lastname: Needham
authors.forename: Donald G
authors.initials: DG
authors.lastname: Patterson
authors.forename: Pier M
authors.initials: PM
authors.lastname: Gerthoux
authors.forename: Paolo
authors.initials: P
authors.lastname: Mocarelli
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D004305:Dose-Response Relationship, Drug; D005260:Female; D006207:Half-Life; D006801:Humans; D007558:Italy; D008297:Male; D000072317:Polychlorinated Dibenzodioxins / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D000072317:Polychlorinated Dibenzodioxins