title: Associations between plasma concentrations of PCB 28 and possible indoor exposure sources in Danish school children and mothers.
abstract: BACKGROUND
  Polychlorinated biphenyls (PCBs) are ubiquitously present in the environment and are suspected of carcinogenic, neurotoxic and immunotoxic effects. Significantly higher plasma concentrations of the congener PCB 28 occur in children compared to adults. Exposure in schools may contribute to this difference.
  
  
  OBJECTIVE
  To determine whether increased blood plasma concentrations of PCB 28 in Danish school children and mothers are associated with living in homes or attending schools constructed in the PCB period (1959-1977).
  
  
  METHODS
  PCB 28 was analyzed in plasma samples from 116 children aged 6-11years and 143 mothers living in an urban and a rural area in Denmark and participating in the European pilot project DEMOCOPHES (Demonstration of a study to COordinate and Perform Human Biomonitoring on a European Scale). In Denmark, PCBs were used in construction in the period 1950-1977, and year of construction or renovation of the homes and schools was used as a proxy for indoor PCB exposure. Linear regression models were used to assess the association between potential PCB exposure from building materials and lipid adjusted concentrations of PCB 28 in plasma, with and without adjustment for potential confounders.
  
  
  RESULTS
  Among the 116 children and 143 mothers, we were able to specify home construction period in all but 4 children and 5 mothers leaving 111 children and 138 mothers for our analyses. The median lipid adjusted plasma PCB 28 concentration was 3 (range: 1-28) ng/g lipid in the children and 2 (range: 1-8) ng/g lipid in the mothers. Children living in homes built in the PCB period had significantly higher lipid adjusted plasma PCB 28 concentrations compared to children living in homes built before or after the PCB period. Following adjustment for covariates, PCB 28 concentrations in children were 40 (95% CI: 13; 68) percent higher than concentrations of children living in homes constructed at other times. Furthermore, children attending schools built or substantially refurbished in the PCB period also had significantly higher (46%, 95% CI: 22; 70) PCB 28 concentrations compared to children attending schools constructed before or after the PCB period, while their mothers had similar concentrations. Adjustment for the most prevalent congener, PCB 153, did not change this effect of home or school construction. When both home and school construction year were included in the models, the increase in lipid adjusted plasma PCB 28 for children living in or attending schools from the PCB period was no longer statistically significant. The individual effect of home and school construction periods could not be evaluated further with the available data.
  
  
  CONCLUSIONS
  Our results suggest that PCB exposure in the indoor environment in schools and homes constructed during the PCB period may contribute significantly to children's plasma PCB 28 concentration. Efforts to minimize PCB exposure in indoor environments should be considered.
authors.affiliation: Section of Environmental Health, Faculty of Health Sciences, University of Copenhagen, Denmark.
authors.forename: Emilie Lund
authors.initials: EL
authors.lastname: Egsmose
authors.affiliation: Department of Construction and Health, Danish Building Research Institute, Aalborg University, Denmark.
authors.forename: Elvira Vaclavik
authors.initials: EV
authors.lastname: Bräuner
authors.affiliation: Department of Construction and Health, Danish Building Research Institute, Aalborg University, Denmark.
authors.forename: Marie
authors.initials: M
authors.lastname: Frederiksen
authors.affiliation: Section of Environmental Health, Faculty of Health Sciences, University of Copenhagen, Denmark.
authors.forename: Thit Aarøe
authors.initials: TA
authors.lastname: Mørck
authors.affiliation: The Research Unit for General Practice and Section of General Practice, Department of Public Health, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Volkert Dirk
authors.initials: VD
authors.lastname: Siersma
authors.affiliation: Section of Environmental Health, Faculty of Health Sciences, University of Copenhagen, Denmark.
authors.forename: Pernille Winton
authors.initials: PW
authors.lastname: Hansen
authors.affiliation: Environmental Medicine, Institute of Public Health, University of Southern Denmark, Odense, Denmark.
authors.forename: Flemming
authors.initials: F
authors.lastname: Nielsen
authors.affiliation: Environmental Medicine, Institute of Public Health, University of Southern Denmark, Odense, Denmark.
authors.forename: Philippe
authors.initials: P
authors.lastname: Grandjean
authors.affiliation: Section of Environmental Health, Faculty of Health Sciences, University of Copenhagen, Denmark. Electronic address: liek@sund.ku.dk.
authors.forename: Lisbeth E
authors.initials: LE
authors.lastname: Knudsen
mesh_terms: D000293:Adolescent; D000328:Adult; D000393:Air Pollutants / Q000097:blood*; D016902:Air Pollution, Indoor / Q000032:analysis*; D002648:Child; D003252:Construction Materials / Q000032:analysis*; D003718:Denmark; D004784:Environmental Monitoring / Q000379:methods*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D009035:Mothers; D011078:Polychlorinated Biphenyls / Q000097:blood*; D012574:Schools / Q000592:standards*; D013334:Students
chemical_list: D000393:Air Pollutants; C081766:2,4,4'-trichlorobiphenyl; D011078:Polychlorinated Biphenyls; C014024:2,4,5,2',4',5'-hexachlorobiphenyl
keywords: Environmental exposure; Homes; PCB-exposed population; Polychlorinated biphenyl; Residents; Year of construction