title: Intra-individual variations and time trends 1991-2001 in human serum levels of PCB, DDE and hexachlorobenzene.
abstract: BACKGROUND
  An important question is whether human serum levels of persistent organic pollutants has continued to decrease during the last decades. The aim of this study was to assess intra-individual variations over time of serum levels of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153), 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethene (p,p'-DDE) and hexachlorobenzene (HCB), considering the impact of a number of possible determinants.
  
  
  METHODS
  Blood samples were drawn for the same 39 subjects in 1991 and 2001. Interviews were made at both occasions. Lipid adjusted serum concentrations of CB-153, p,p'-DDE and HCB were determined in both sets of blood samples using gas chromatography-mass spectrometry. The fatty acid composition of the serum lipids was analyzed by means of gas-liquid chromatography.
  
  
  RESULTS
  The CB-153 concentrations in serum had averagely decreased with 34% in between 1991 and 2001 (p<0.001). Of individual determinants only increasing BMI was associated with decreasing CB-153 levels (beta=-1.0, 95% CI -1.8, -0.2, p=0.01), explaining 13% of the variation. The average decrease of p,p'-DDE was 55%, and could only weakly be associated with a relative increase of BMI (beta=-1.0, 95% CI -2.3, 0.2, p=0.09), explaining only 5% of the variation. The average decrease of HCB was 53%, and was associated only with high fish consumption in 1991, explaining 12% of the variation.
  
  
  CONCLUSIONS
  The results support a continuing decrease in human body burdens of PCBs, DDE and HCB during the 1990s. The explanatory factors relative change of BMI and fish consumption explained only a minor part of the time-related variations in serum levels.
authors.affiliation: Division of Occupational and Environmental Medicine and Psychiatric Epidemiology, Department of Laboratory Medicine, Lund University Hospital, SE-221 85 Lund, Sweden. lars.hagmar@med.lu.se
authors.forename: Lars
authors.initials: L
authors.lastname: Hagmar
authors.forename: Ewa
authors.initials: E
authors.lastname: Wallin
authors.forename: Bengt
authors.initials: B
authors.lastname: Vessby
authors.forename: Bo Ag
authors.initials: BA
authors.lastname: Jönsson
authors.forename: Ake
authors.initials: A
authors.lastname: Bergman
authors.forename: Lars
authors.initials: L
authors.lastname: Rylander
mesh_terms: D000328:Adult; D000368:Aged; D003633:Dichlorodiphenyl Dichloroethylene / Q000097:blood*; D004032:Diet; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000097:blood*; D006581:Hexachlorobenzene / Q000097:blood*; D006801:Humans; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D011078:Polychlorinated Biphenyls / Q000097:blood*; D017747:Seafood; D013548:Sweden; D013997:Time Factors
chemical_list: D004785:Environmental Pollutants; D008055:Lipids; D003633:Dichlorodiphenyl Dichloroethylene; D006581:Hexachlorobenzene; D011078:Polychlorinated Biphenyls