Table of Contents

Component Description

Polybrominated diphenyl ethers (PBDEs) are included in a larger group of chemicals known as brominated flame retardants and they are added to products such as foam padding, textiles, or plastics to retard combustion. PBDEs are not chemically bound to the flame-retarded material, so they can enter the environment from volatilization, leaching, or degradation of PBDE-containing products. PBDEs are generally persistent in the environment and have been measured in aquatic sediments, house dust, and aquatic and terrestrial animals, especially in fish where PBDEs are known to bioconcentrate. Hence humans may be exposed though the diet, including breast feeding, and by contact with flame retarded products and contaminated house dust. The rate of elimination of PDBEs from the human body depends on the specific PDBE, with elimination half-lives that can vary from a couple weeks to several months.

Eligible Sample

Participants aged 12 years and older who met the subsample requirements.

Description of Laboratory Methodology

The method described in this manual assesses human body burden of BFRs, specifically PBDEs in serum and/or plasma. This is done by measuring the concentration in serum/plasma through the use of solid-phase extraction (SPE) and subsequent sample clean-up. Final determination of target analytes is performed by isotope dilution gas chromatography high-resolution mass spectrometry GC/IDHRMS.

Concentrations of target analytes are reported on two different bases, i.e., (i) fresh weight basis (i.e., pg/g serum) and (ii) lipid weight basis (i.e., ng/g lipid). Lipid adjusted concentration values are preferable because (i) organohalogen compounds are lipophilic and hence distribute in the body mainly according to the tissues lipid content. Lipid adjusted concentrations correlates with the adipose tissue concentrations of the chemical. Normalization according to lipid content further reduces variability since differences in individuals serum lipid concentrations are cancelled out.

The samples are extracted using SPE, employing an automated SPE workstation (Rapid Trace® , Caliper Life Sciences). Required sample pretreatment prior to extraction is performed on the Gilson 215 liquid handler, including automated addition of (i) internal standards, (ii) formic acid (denaturant) and (iii) water (diluent) with mixing in-between each addition by rotation. Formic acid is added to denature proteins in the sample enabling extraction of target compounds. During the extraction step the target analytes are transferred from a water medium to an organic solvent.

Sample cleanup, i.e., removal of co-extracted lipids, is obtained by elution (hexane; 8 mL) of the extract through a column containing from the top 0.1 g of silica and 1 g of silica/sulfuric acid (33% by weight). During this procedure serum lipids are degraded in the sulfuric acid layer while cholesterol is removed in the top layer consisting of activated silica gel. Without the activated silica gel layer cholesterol would eliminate water forming cholestene when coming in contact with the sulfuric acid. Cholestene would not be removed in the silica gel/sulfuric acid layer and interfere in the final HR-MS analyses, i.e., causing an ion suppression in the region of 2,2’,4,4’,5 pentabromodiphenyl ether (BDE-99) and 2,2’,4,4’,6-pentabromodiphenyl ether (BDE-100).

This sample cleanup is automated using the Rapid Trace® (Caliper Life Sciences) also used for sample extraction. The samples are evaporated and transferred to GC vials. Evaporization is performed on the RapidVap® (LabConco), using vacuum, increased temperature and vortex action to aid the evaporization.

Serum concentrations are determined using gas chromatography isotope dilution high resolution mass spectrometry (GC/IDHRMS), which minimizes or eliminates many interferences associated with low-resolution measurement of organohalogen compounds. Splitless injection is used employing a short GC column (DB-5HT; 15 m length, 0.1 μm film thickness, 0.25 mm ID) enabling the determination of high molecular weight compounds such as decabromodiphenyl ether (BDE-209) having a molecular weight close to 1000 amu. Electron impact ionization (EI) is used. The two most abundant ions in the isotopic cluster (fragment or molecular ion) are monitored for the target analyte as well as for the 13C-labeled internal-surrogate standard. Quantification is made against a calibration curve covering the full concentration range of the target analytes.

Laboratory Quality Assurance and Monitoring

Serum specimens are processed, stored, and shipped to the Division of Environmental Health Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention for analysis.

Detailed specimen collection and processing instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM). Vials are stored under appropriate frozen (–20°C) conditions until they are shipped to National Center for Environmental Health for testing.

Mobile Examination Centers (MECs)

Laboratory team performance is monitored using several techniques. NCHS and contract consultants use a structured quality assurance evaluation during unscheduled visits to evaluate both the quality of the laboratory work and the quality-control procedures. Each laboratory staff person is observed for equipment operation, specimen collection and preparation; testing procedures and constructive feedback is given to each staff. Formal retraining sessions are conducted annually to ensure that required skill levels were maintained.

The NHANES QA/QC protocols meet the 1988 Clinical Laboratory Improvement Act mandates. Detailed QA/QC instructions are discussed in the NHANES LPM.

Analytical Laboratories

NHANES uses several methods to monitor the quality of the analyses performed by the contract laboratories. In the MEC, these methods include performing blind split samples collected on “dry run” sessions. In addition, contract laboratories randomly perform repeat testing on 2.0% of all specimens.

NCHS developed and distributed a quality control protocol for all the contract laboratories which outlined the Westgard rules used when running NHANES specimens. Progress reports containing any problems encountered during shipping or receipt of specimens, summary statistics for each control pool, QC graphs, instrument calibration, reagents, and any special considerations are submitted to NCHS and Westat quarterly. The reports are reviewed for trends or shifts in the data. The laboratories are required to explain any identified areas of concern.

All QC procedures recommended by the manufacturers were followed. Reported results for all assays meet the Division of Laboratory Science’s quality control and quality assurance performance criteria for accuracy and precision (similar to specifications outlined by Westgard (1981).

Analytic Notes

Subsample weights

Measures of serum polybrominated diphenyl ethers (PBDE) were measured in a one third subsample of persons 12 years and over. Special sample weights are required to analyze these data properly. Specific sample weights for this subsample are included in this data file and should be used when analyzing these data.

Variance estimation

The analysis of NHANES 2003-2004 laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES 2003-2004 Demographic Data File contains demographic and sample design variables. The recommended procedure for variance estimation requires use of stratum and PSU variables (SDMVSTRA and SDMVPSU, respectively) in the demographic data file.

Links to NHANES Data Files

This laboratory data file can be linked to the other NHANES 2003-2004 data files using the unique survey participant identifier SEQN.

Detection Limits

The detection limits were variable for all of the analytes in the data set. Two variables are provided for each of these analytes. The variable named LBD___LC indicates whether the result was below the limit of detection. There are two values: “0” and “1”. “0” means that the result was at or above the limit of detection. “1” indicates that the result was below the limit of detection.

The other variable named LBX___ provides the analytic result for that analyte.

Please refer to the Analytic Guidelines for further details on the use of sample weights and other analytic issues.

References

Codebook and Frequencies

SEQN - Respondent sequence number

Variable Name:
SEQN
SAS Label:
Respondent sequence number
English Text:
Respondent sequence number.
Target:
Both males and females 12 YEARS - 150 YEARS

WTSB2YR - Two-year MEC weights of subsample B

Variable Name:
WTSB2YR
SAS Label:
Two-year MEC weights of subsample B
English Text:
Two-year MEC weights of subsample B
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 435025.30254 Range of Values 2337 2337
. Missing 0 2337

LBXBB1 - 2,2',4,4',5,5'-hexabromobiphenyl

Variable Name:
LBXBB1
SAS Label:
2,2',4,4',5,5'-hexabromobiphenyl
English Text:
2,2',4,4',5,5'-hexabromobiphenyl (pg/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.2 to 2943.1 Range of Values 2032 2032
. Missing 305 2337

LBXBB1LA - 2,2',4,4',5,5'-hexbrombiphenyl lipid adj

Variable Name:
LBXBB1LA
SAS Label:
2,2',4,4',5,5'-hexbrombiphenyl lipid adj
English Text:
2,2',4,4',5,5'-hexabromobiphenyl lipid adjusted (ng/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.1 to 225 Range of Values 2032 2032
. Missing 305 2337

LBDBB1LC - 2,2',4,4',5,5'-hexabromobiphenyl comment

Variable Name:
LBDBB1LC
SAS Label:
2,2',4,4',5,5'-hexabromobiphenyl comment
English Text:
2,2',4,4',5,5'-hexabromobiphenyl comment code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1485 1485
1 Below lower detection limit 547 2032
. Missing 305 2337

LBXBR1 - 2,2',4-tribromodiphenyl ether

Variable Name:
LBXBR1
SAS Label:
2,2',4-tribromodiphenyl ether
English Text:
2,2',4-tribromodiphenyl ether (pg/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.2 to 87.4 Range of Values 1992 1992
. Missing 345 2337

LBXBR1LA - 2,2',4-tribromodiphenyl ether lipid adj

Variable Name:
LBXBR1LA
SAS Label:
2,2',4-tribromodiphenyl ether lipid adj
English Text:
2,2',4-tribromodiphenyl ether lipid adjusted (ng/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.1 to 20.6 Range of Values 1992 1992
. Missing 345 2337

LBDBR1LC - 2,2',4-tribromodiphenyl ether comment

Variable Name:
LBDBR1LC
SAS Label:
2,2',4-tribromodiphenyl ether comment
English Text:
2,2',4-tribromodiphenyl ether comment code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 100 100
1 Below lower detection limit 1892 1992
. Missing 345 2337

LBXBR2 - 2,4,4'-tribromodiphenyl ether

Variable Name:
LBXBR2
SAS Label:
2,4,4'-tribromodiphenyl ether
English Text:
2,4,4'-tribromodiphenyl ether (pg/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.2 to 465.8 Range of Values 1987 1987
. Missing 350 2337

LBXBR2LA - 2,4,4'-tribromodiphenyl ether lipid adj

Variable Name:
LBXBR2LA
SAS Label:
2,4,4'-tribromodiphenyl ether lipid adj
English Text:
2,4,4'-tribromodphenyl ether lipid adjusted (ng/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.1 to 65.2 Range of Values 1987 1987
. Missing 350 2337

LBDBR2LC - 2,4,4'-tribromodiphenyl ether comment

Variable Name:
LBDBR2LC
SAS Label:
2,4,4'-tribromodiphenyl ether comment
English Text:
2,4,4'-tribromodiphenyl ether comment code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1601 1601
1 Below lower detection limit 386 1987
. Missing 350 2337

LBXBR3 - 2,2',4,4'-tetrabromodiphenyl ether

Variable Name:
LBXBR3
SAS Label:
2,2',4,4'-tetrabromodiphenyl ether
English Text:
2,2',4,4'-tetrabromodiphenyl ether (pg/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
9.8 to 13346.5 Range of Values 2016 2016
. Missing 321 2337

LBXBR3LA - 2,2',4,4'-tetrabromphenyl ether lipid ad

Variable Name:
LBXBR3LA
SAS Label:
2,2',4,4'-tetrabromphenyl ether lipid ad
English Text:
2,2',4,4'-tetrabromodiphenyl ether lipid adjusted (ng/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.1 to 2350 Range of Values 2016 2016
. Missing 321 2337

LBDBR3LC - 2,2',4,4'-tetrabromphenyl ether comment

Variable Name:
LBDBR3LC
SAS Label:
2,2',4,4'-tetrabromphenyl ether comment
English Text:
2,2',4,4'-tetrabromodiphenyl ether comment code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1975 1975
1 Below lower detection limit 41 2016
. Missing 321 2337

LBXBR4 - 2,2',3,4,4'-pentabromodiphenyl ether

Variable Name:
LBXBR4
SAS Label:
2,2',3,4,4'-pentabromodiphenyl ether
English Text:
2,2',3,4,4'-pentabromodiphenyl ether (pg/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3 to 450 Range of Values 2000 2000
. Missing 337 2337

LBXBR4LA - 2,2',3,4,4'-pentabromphenyl lipid adj

Variable Name:
LBXBR4LA
SAS Label:
2,2',3,4,4'-pentabromphenyl lipid adj
English Text:
2,2',3,4,4'-pentabromodiphenyl ether lipid adjusted (ng/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.2 to 66.9 Range of Values 2000 2000
. Missing 337 2337

LBDBR4LC - 2,2',3,4,4'-pentabromphenyl ether comt

Variable Name:
LBDBR4LC
SAS Label:
2,2',3,4,4'-pentabromphenyl ether comt
English Text:
2,2',3,4,4'-pentabromodiphenyl ether comment code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 512 512
1 Below lower detection limit 1488 2000
. Missing 337 2337

LBXBR5 - 2,2',4,4',5-pentabromodiphenyl ether

Variable Name:
LBXBR5
SAS Label:
2,2',4,4',5-pentabromodiphenyl ether
English Text:
2,2’,4,4’,5-pentabromodiphenyl ether (pg/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7.3 to 5620.3 Range of Values 1985 1985
. Missing 352 2337

LBXBR5LA - 2,2',4,4',5-pentabromphenyl lipid adj

Variable Name:
LBXBR5LA
SAS Label:
2,2',4,4',5-pentabromphenyl lipid adj
English Text:
2,2',4,4',5-pentabromodiphenyl ether lipid adjusted (ng/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.8 to 692 Range of Values 1985 1985
. Missing 352 2337

LBDBR5LC - 2,2',4,4',5-pentabromphenyl ether comt

Variable Name:
LBDBR5LC
SAS Label:
2,2',4,4',5-pentabromphenyl ether comt
English Text:
2,2',4,4',5-pentabromodiphenyl ether comment code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1395 1395
1 Below lower detection limit 590 1985
. Missing 352 2337

LBXBR6 - 2,2',4,4',6-pentabromodiphenyl ether

Variable Name:
LBXBR6
SAS Label:
2,2',4,4',6-pentabromodiphenyl ether
English Text:
2,2',4,4',6-pentabromodiphenyl ether (pg/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2.8 to 3185.8 Range of Values 2040 2040
. Missing 297 2337

LBXBR6LA - 2,2',4,4',6-pentabromdphenyl lipid adj

Variable Name:
LBXBR6LA
SAS Label:
2,2',4,4',6-pentabromdphenyl lipid adj
English Text:
2,2',4,4',6-pentabromodiphenyl ether lipid adjusted (ng/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.4 to 365 Range of Values 2040 2040
. Missing 297 2337

LBDBR6LC - 2,2',4,4',6-pentabromdphenyl ether comt

Variable Name:
LBDBR6LC
SAS Label:
2,2',4,4',6-pentabromdphenyl ether comt
English Text:
2,2',4,4',6-pentabromodiphenyl ether comment code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1918 1918
1 Below lower detection limit 122 2040
. Missing 297 2337

LBXBR7 - 2,2',4,4',5,5'-hexabromodiphenyl ether

Variable Name:
LBXBR7
SAS Label:
2,2',4,4',5,5'-hexabromodiphenyl ether
English Text:
2,2',4,4',5,5'-hexabromodiphenyl ether (pg/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
4.2 to 5432.5 Range of Values 2039 2039
. Missing 298 2337

LBXBR7LA - 2,2',4,4',5,5'-hexabromphenyl lipid adj

Variable Name:
LBXBR7LA
SAS Label:
2,2',4,4',5,5'-hexabromphenyl lipid adj
English Text:
2,2',4,4',5,5'-hexabromodiphenyl ether lipid adjusted (ng/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.4 to 821 Range of Values 2039 2039
. Missing 298 2337

LBDBR7LC - 2,2',4,4',5,5'-hexabromphenyl ether comt

Variable Name:
LBDBR7LC
SAS Label:
2,2',4,4',5,5'-hexabromphenyl ether comt
English Text:
2,2',4,4',5,5'-hexabromodiphenyl ether comment code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1915 1915
1 Below lower detection limit 124 2039
. Missing 298 2337

LBXBR8 - 2,2',4,4',5,6'-hexabromodiphenyl ether

Variable Name:
LBXBR8
SAS Label:
2,2',4,4',5,6'-hexabromodiphenyl ether
English Text:
2,2',4,4',5,6'-hexabromodiphenyl ether (pg/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.2 to 428.6 Range of Values 2014 2014
. Missing 323 2337

LBXBR8LA - 2,2',4,4',5,6'-hexabromphenyl lipid adj

Variable Name:
LBXBR8LA
SAS Label:
2,2',4,4',5,6'-hexabromphenyl lipid adj
English Text:
2,2',4,4',5,6'-hexabromodiphenyl ether lipid adjusted (ng/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.1 to 40.5 Range of Values 2014 2014
. Missing 323 2337

LBDBR8LC - 2,2',4,4',5,6'-hexabromphenyl ether comt

Variable Name:
LBDBR8LC
SAS Label:
2,2',4,4',5,6'-hexabromphenyl ether comt
English Text:
2,2',4,4',5,6'-hexabromodiphenyl ether comment code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1110 1110
1 Below lower detection limit 904 2014
. Missing 323 2337

LBXBR9 - 2,2',3,4,4',5',6-heptabromodiphenyl ethr

Variable Name:
LBXBR9
SAS Label:
2,2',3,4,4',5',6-heptabromodiphenyl ethr
English Text:
2,2',3,4,4',5',6-heptabromodiphenyl ether (pg/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2.2 to 125 Range of Values 1993 1993
. Missing 344 2337

LBXBR9LA - 2,2',3,4,4',5',6-heptabrophenl lipid adj

Variable Name:
LBXBR9LA
SAS Label:
2,2',3,4,4',5',6-heptabrophenl lipid adj
English Text:
2,2',3,4,4',5',6-heptabromodiphenyl lipid adjusted (ng/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.1 to 21.1 Range of Values 1993 1993
. Missing 344 2337

LBDBR9LC - 2,2',3,4,4',5',6-heptabrophenl ether cmt

Variable Name:
LBDBR9LC
SAS Label:
2,2',3,4,4',5',6-heptabrophenl ether cmt
English Text:
2,2',3,4,4',5',6-heptabromodiphenyl ether comment code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 319 319
1 Below lower detection limit 1674 1993
. Missing 344 2337

LBXBR66 - 2,3',4,4'-tetrabromodiphenyl ether

Variable Name:
LBXBR66
SAS Label:
2,3',4,4'-tetrabromodiphenyl ether
English Text:
2,3',4,4'-tetrabromodiphenyl ether (pg/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.2 to 109.8 Range of Values 1999 1999
. Missing 338 2337

LBXBR66L - 2,3',4,4'-tetrabromodiphenyl lipid adj

Variable Name:
LBXBR66L
SAS Label:
2,3',4,4'-tetrabromodiphenyl lipid adj
English Text:
2,3',4,4'-tetrabromodiphenyl ether lipid adjusted (ng/g)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.1 to 17.4 Range of Values 1999 1999
. Missing 338 2337

LBDBR66C - 2,3',4,4'-tetrabromodiphenyl ether comt

Variable Name:
LBDBR66C
SAS Label:
2,3',4,4'-tetrabromodiphenyl ether comt
English Text:
2,3',4,4'-tetrabromodiphenyl ether comment code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 449 449
1 Below lower detection limit 1550 1999
. Missing 338 2337