Table of Contents

Component Description

Urinary Polyaromatic Hydrocarbons (PAHs)

PAHs constitute a group of chemicals which are formed during the incomplete combustion of coal, oil and gas, garbage, and other organic substances. In general, people are exposed to mixtures of PAHs, and the sources are widespread, including vehicle exhausts, asphalt, coal tar, wild fires, agricultural burning, charbroiled foods, and tobacco smoke. PAHs enter the body quickly and easily by all routes of exposure and are readily and predominantly metabolized to hydroxylated metabolites and glucuronide metabolites. These compounds require metabolic activation in order to interact with cellular macromolecules. Measurement of urinary metabolites indicates exposure to the parent PAHs. Although background ranges of PAHs in air and water are known, less is known about PAH background levels in humans.

Eligible Sample

Examined participants aged 6 years and older from a one-third sample.

Description of Laboratory Methodology

The specific analytes measured in this method are monohydroxylated metabolites of PAHs (OH-PAHs). This procedure involves enzymatic hydrolysis of glucuronidated/sulfated OH-PAH metabolites in urine, extraction, derivatization, and analysis using isotope dilution capillary gas chromatog¬raphy tandem mass spectrometry (GC-MS/MS). Ion transitions specific to each analyte and carbon-13 labeled internal standards are monitored, and the abundances of each ion are measured.

Refer to NHANES 2011-2012 Lab Methods for Monohydroxy-Polycyclic Aromatic Hydrocarbons (OH-PAHs) for detailed description of the laboratory method used.

Data Processing and Editing

The data were reviewed. Incomplete data or improbable values were sent to the performing laboratory for confirmation.

Laboratory Quality Assurance and Monitoring

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

Detailed instructions on specimen collection and processing are discussed in the NHANES Laboratory 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 are 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 laboratories. NCEH developed and distributed a quality control protocol for all the laboratories which outlined the Westgard rules (Westgard et al, 1981) used when running NHANES specimens. Summary statistics for each control pool, QC graphs, and any special considerations are submitted to NCHS. NCHS reviewed the data for trends or shifts. 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 the Westgard rules (Westgard et al, 1981).

Analytic Notes

Refer to the 2011-2012 Laboratory Data Overview for general information on NHANES laboratory data.

Subsample weights

Measures of urinary PAHs were measured in a one third subsample of persons 6 years and older. 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  laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES 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 data files using the unique survey participant identifier SEQN.

Detection Limits

The detection limits were constant for all of the analytes in the data set. Two variables are provided for each of these analytes. The variable named URD___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 URX___ provides the analytic result for that analyte. For analytes with analytic results below the lower limit of detection (i.e., URD___LC=1), an imputed fill value was placed in the analyte results field. This value is the lower limit of detection divided by square root of 2 (LLOD/sqrt(2)).

The lower limit of detection (LLOD, in ng/L) for urinary PAHs:

Analyte Item ID LLOD
Urinary 2-Hydroxyfluorene URXP04 10.0
Urinary 3-Hydroxyfluorene URXP03 10.0
Urinary 9-Hydroxyfluorene URXP17 10.0
Urinary 1-Hydroxyphenanthrene URXP06 10.0
Urinary 2-Hydroxyphenanthrene URXP07 10.0
Urinary 3-Hydroxyphenanthrene URXP05 10.0
Urinary 1-Hydroxypyrene URXP10 10.0
Urinary 1-Hydroxynapthalene (1-Naphthol) URXP01 44.0
Urinary 2-Hydroxynapthalene (2-Naphthol) URXP02 42.0
Urinary 4-Hydroxyphenanthrene URXP19 10.0

Please refer to the NHANES Analytic Guidelines and the on-line NHANES Tutorial 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 6 YEARS - 150 YEARS

WTSA2YR - Subsample A weights

Variable Name:
WTSA2YR
SAS Label:
Subsample A weights
English Text:
Subsample A weights
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
12199.652219 to 643202.3505 Range of Values 2551 2551
. Missing 43 2594

URXP01 - 1-hydroxynaphthalene (ng/L)

Variable Name:
URXP01
SAS Label:
1-hydroxynaphthalene (ng/L)
English Text:
1-hydroxynaphthalene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
31.1 to 16658076 Range of Values 2492 2492
. Missing 102 2594

URDP01LC - 1-hydroxynaphthalene comment code

Variable Name:
URDP01LC
SAS Label:
1-hydroxynaphthalene comment code
English Text:
1-hydroxynaphthalene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2490 2490
1 Below lower detection limit 2 2492
. Missing 102 2594

URXP02 - 2-hydroxynaphthalene (ng/L)

Variable Name:
URXP02
SAS Label:
2-hydroxynaphthalene (ng/L)
English Text:
2-hydroxynaphthalene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
99 to 183014 Range of Values 2492 2492
. Missing 102 2594

URDP02LC - 2-hydroxynaphthalene comment code

Variable Name:
URDP02LC
SAS Label:
2-hydroxynaphthalene comment code
English Text:
2-hydroxynaphthalene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2492 2492
1 below lower detection limit 0 2492
. Missing 102 2594

URXP03 - 3-hydroxyfluorene (ng/L)

Variable Name:
URXP03
SAS Label:
3-hydroxyfluorene (ng/L)
English Text:
3-hydroxyfluorene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7.1 to 6541 Range of Values 2488 2488
. Missing 106 2594

URDP03LC - 3-hydroxyfluorene comment code

Variable Name:
URDP03LC
SAS Label:
3-hydroxyfluorene comment code
English Text:
3-hydroxyfluorene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2440 2440
1 Below lower detection limit 48 2488
. Missing 106 2594

URXP04 - 2-hydroxyfluorene (ng/L)

Variable Name:
URXP04
SAS Label:
2-hydroxyfluorene (ng/L)
English Text:
2-hydroxyfluorene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
11 to 15068 Range of Values 2492 2492
. Missing 102 2594

URDP04LC - 2-hydroxyfluorene comment code

Variable Name:
URDP04LC
SAS Label:
2-hydroxyfluorene comment code
English Text:
2-hydroxyfluorene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2492 2492
1 Below lower detection limit 0 2492
. Missing 102 2594

URXP05 - 3-hydroxyphenanthrene (ng/L)

Variable Name:
URXP05
SAS Label:
3-hydroxyphenanthrene (ng/L)
English Text:
3-hydroxyphenanthrene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7.1 to 6683 Range of Values 2491 2491
. Missing 103 2594

URDP05LC - 3-hydroxyphenanthrene comment code

Variable Name:
URDP05LC
SAS Label:
3-hydroxyphenanthrene comment code
English Text:
3-hydroxyphenanthrene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2409 2409
1 Below lower detection limit 82 2491
. Missing 103 2594

URXP06 - 1-hydroxyphenanthrene (ng/L)

Variable Name:
URXP06
SAS Label:
1-hydroxyphenanthrene (ng/L)
English Text:
1-hydroxyphenanthrene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7.1 to 7475 Range of Values 2492 2492
. Missing 102 2594

URDP06LC - 1-hydroxyphenanthrene comment code

Variable Name:
URDP06LC
SAS Label:
1-hydroxyphenanthrene comment code
English Text:
1-hydroxyphenanthrene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2489 2489
1 Below lower detection limit 3 2492
. Missing 102 2594

URXP07 - 2-hydroxyphenanthrene (ng/L)

Variable Name:
URXP07
SAS Label:
2-hydroxyphenanthrene (ng/L)
English Text:
2-hydroxyphenanthrene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7.1 to 3262 Range of Values 2489 2489
. Missing 105 2594

URDP07LC - 2-hydroxyphenanthrene comment code

Variable Name:
URDP07LC
SAS Label:
2-hydroxyphenanthrene comment code
English Text:
2-hydroxyphenanthrene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2427 2427
1 Below lower detection limit 62 2489
. Missing 105 2594

URXP10 - 1-hydroxypyrene (ng/L)

Variable Name:
URXP10
SAS Label:
1-hydroxypyrene (ng/L)
English Text:
1-hydroxypyrene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7.1 to 5474 Range of Values 2487 2487
. Missing 107 2594

URDP10LC - 1-hydroxypyrene comment code

Variable Name:
URDP10LC
SAS Label:
1-hydroxypyrene comment code
English Text:
1-hydroxypyrene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2458 2458
1 Below lower detection limit 29 2487
. Missing 107 2594

URXP17 - 9-hydroxyfluorene (ng/L)

Variable Name:
URXP17
SAS Label:
9-hydroxyfluorene (ng/L)
English Text:
9-hydroxyfluorene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7.1 to 19009 Range of Values 2491 2491
. Missing 103 2594

URDP17LC - 9-hydroxyfluorene comment code

Variable Name:
URDP17LC
SAS Label:
9-hydroxyfluorene comment code
English Text:
9-hydroxyfluorene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2489 2489
1 Below lower detection limit 2 2491
. Missing 103 2594

URXP19 - 4-phenanthrene (ng/L)

Variable Name:
URXP19
SAS Label:
4-phenanthrene (ng/L)
English Text:
4-phenanthrene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7.1 to 951 Range of Values 2487 2487
. Missing 107 2594

URDP19LC - 4-phenanthrene comment code

Variable Name:
URDP19LC
SAS Label:
4-phenanthrene comment code
English Text:
4-phenanthrene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1902 1902
1 Below lower detection limit 585 2487
. Missing 107 2594

URXUCR - Urinary creatinine

Variable Name:
URXUCR
SAS Label:
Urinary creatinine
English Text:
Urinary creatinine
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
4 to 800 Range of Values 2525 2525
. Missing 69 2594