Table of Contents

Locator Record

Title: Urinary Phthalates (L24PH_C )
Contact Number: 1-866-441-NCHS
Years of Content: 2003 - 2004
First Published: January, 2008
Revised: NA
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject:Urinary Phthalates
Record Source: NHANES 2003 - 2004
Survey Methodology: NHANES 2003 - 2004 is a stratified multistage probability sample of the civilian non-institutionalized population of the U.S.
Medium: NHANES Web site; SAS transport files

Component Description

Urinary Phthalates

Phthalate acid esters (phthalates) have been used extensively as plasticizers in a wide range of applications such as children’s toys, food packaging, personal care products, and medical supplies. Because some of these compounds have been shown to bind to estrogen receptors and have been associated with estrogenic effects in laboratory animals, increasing concerns have been expressed about phthalate usage in food packaging materials, personal care products, and children’s toys. Measurement of urinary phthalate metabolites in humans is useful to evaluate recent exposure and potential human health effects from these chemicals.

Eligible Sample

Participants aged 6 years and older who met the subsample requirements.

Description of Laboratory Methodology

The test principle utilizes high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) for the quantitative detection in urine of the following phthalate metabolites: monomethyl phthalate (mMP), monoethyl phthalate (mEP), monobutyl phthalate (mBP), mono-isobutyl phthalate (miBP), mono (3-carboxypropyl) phthalate (mCPP), monocyclohexyl phthalate (mCHP), mono (2-ethylhexyl) phthalate (mEHP), monooctyl phthalate (mOP), monobenzyl phthalate (mBzP), monoisononyl phthalate (mNP), mono(2-ethyl-5-oxohexyl) phthalate (mEOHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (mEHHP), and mono(2-ethyl-5-carboxypentyl) phthalate (mECPP) [1]. Urine samples are processed using enzymatic deconjugation of the glucuronidated phthalate monoesters followed by on-line solid phase extraction (SPE) coupled with reversed phase HPLC-ESI-MS/MS. Assay precision is improved by incorporating isotopically-labeled internal standards for each of the phthalate metabolites. In addition, 4-methyl umbelliferone glucuronide is used to monitor deconjugation efficiency. This selective method allows for rapid detection of up to fifteen monoester metabolites of commonly used phthalate diesters in human urine with limits of detection in the low parts per billion (ppb) ranges.

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 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 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. 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.

NCEH developed and distributed a quality control protocol for all the laboratories which outlined the Westgard rules used when running NHANES specimens. Any problems encountered during shipping or receipt of specimens, instrument calibration, reagents, and any special considerations are submitted to NCHS and Westat. Summary statistics for each control pool, QC graphs, are reviewed by NCHS 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 Sciences’ quality control and quality assurance performance criteria for accuracy and precision (similar to specifications outlined by Westgard (1981). 

Analytic Notes

Mono-ethyl phthalate (URXMEP), Mono-benzyl phthalate (URXMZP), Mono-n-octyl phthalate (URXMOP), Mono-isononyl phthalate (URXMNP), and Mono-cyclohexyl phthalate (URXMCP):
NHANES recently learned that analytical standards used since 1999 and used for several metabolites were of insufficient purity. As a result of further investigation, a correction factor was applied to each value for the 5 metabolites.

Subsample weights

Measures of urinary environmentals were measured in a one third subsample of persons 6 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 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.

The lower limit of detections for the environmental phthalates is:

Analyte  Item ID  Limit of Detection (LLOD) 
Mono-2-ethyl-5-carboxypentyl phthalate URXECP 0.25
Mono-n-butyl phthalate (ng/mL) URXMBP 0.40
Mono-(3-carboxypropyl) phthalate (ng/mL) URXMC1 0.16
Mono-cyclohexyl phthalate (ng/mL) URXMCP 0.402
Mono-ethyl phthalate (ng/mL) URXMEP 0.264
Mono-(2-ethyl-5-hydroxyhexyl) (ng/mL) URXMHH 0.32
Mono-(2-ethyl)-hexyl phthalate (ng/mL) URXMHP 0.90
Mono-isobutyl phthalate (ng/mL) URXMIB 0.26
Mono-n-methyl phthalate (ng/mL) URXMNM 1.0
Mono-isononyl phthalate (ng/mL) URXMNP 1.54
Mono-(2-ethyl-5-oxohexyl) (ng/mL) URXMOH 0.45
Mono-n-octyl phthalate URXMOP 1.68
Mono-benzyl phthalate (ng/mL) URXMZP 0.072

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 6 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 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 435025.30254 Range of Values 2697 2697
. Missing 0 2697

URXMBP - Mono-n-butyl phthalate

Variable Name:
URXMBP
SAS Label:
Mono-n-butyl phthalate
English Text:
Mono-n-butyl phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.3 to 5143.2 Range of Values 2605 2605
. Missing 92 2697

URDMBPLC - Mono-n-butyl phthalate comment code

Variable Name:
URDMBPLC
SAS Label:
Mono-n-butyl phthalate comment code
English Text:
mono-n-butyl phthalate 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 2593 2593
1 Below lower detection limit 12 2605
. Missing 92 2697

URXMCP - Mono-cyclohexyl phthalate

Variable Name:
URXMCP
SAS Label:
Mono-cyclohexyl phthalate
English Text:
Mono-cyclohexyl phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.2843 to 62.31 Range of Values 2605 2605
. Missing 92 2697

URDMCPLC - Mono-cyclohexyl phthalate comment

Variable Name:
URDMCPLC
SAS Label:
Mono-cyclohexyl phthalate comment
English Text:
mono-cyclohexyl phthalate 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 281 281
1 Below lower detection limit 2324 2605
. Missing 92 2697

URXMEP - Mono-ethyl phthalate

Variable Name:
URXMEP
SAS Label:
Mono-ethyl phthalate
English Text:
Mono-ethyl phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2.31 to 30589.02 Range of Values 2605 2605
. Missing 92 2697

URDMEPLC - Mono-ethyl phthalate comment code

Variable Name:
URDMEPLC
SAS Label:
Mono-ethyl phthalate comment code
English Text:
mono-ethyl phthalate 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 2605 2605
1 Below lower detection limit 0 2605
. Missing 92 2697

URXMHP - Mono-(2-ethyl)-hexyl phthalate

Variable Name:
URXMHP
SAS Label:
Mono-(2-ethyl)-hexyl phthalate
English Text:
Mono-(2-ethyl)-hexyl phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.6 to 718 Range of Values 2605 2605
. Missing 92 2697

URDMHPLC - Mono-(2-ethyl)-hexyl phthalate comment

Variable Name:
URDMHPLC
SAS Label:
Mono-(2-ethyl)-hexyl phthalate comment
English Text:
Mono-(2-ethyl)-hexyl phthalate 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 1826 1826
1 Below lower detection limit 779 2605
. Missing 92 2697

URXMNP - Mono-isononyl phthalate

Variable Name:
URXMNP
SAS Label:
Mono-isononyl phthalate
English Text:
Mono-isononyl phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.0889 to 44.814 Range of Values 2605 2605
. Missing 92 2697

URDMNPLC - Mono-isononyl phthalate comment code

Variable Name:
URDMNPLC
SAS Label:
Mono-isononyl phthalate comment code
English Text:
Mono-isononyl phthalate 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 152 152
1 Below lower detection limit 2453 2605
. Missing 92 2697

URXMOP - Mono-n-octyl phthalate

Variable Name:
URXMOP
SAS Label:
Mono-n-octyl phthalate
English Text:
Mono-n-octyl phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.1879 to 27.216 Range of Values 2605 2605
. Missing 92 2697

URDMOPLC - Mono-n-octyl phthalate comment code

Variable Name:
URDMOPLC
SAS Label:
Mono-n-octyl phthalate comment code
English Text:
Mono-n-octyl phthalate 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 27 27
1 Below lower detection limit 2578 2605
. Missing 92 2697

URXMZP - Mono-benzyl phthalate

Variable Name:
URXMZP
SAS Label:
Mono-benzyl phthalate
English Text:
Mono-benzyl phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.056 to 862.272 Range of Values 2605 2605
. Missing 92 2697

URDMZPLC - Mono-benzyl phthalate comment code

Variable Name:
URDMZPLC
SAS Label:
Mono-benzyl phthalate comment code
English Text:
Mono-benzyl phthalate 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 2596 2596
1 Below lower detection limit 9 2605
. Missing 92 2697

URXMNM - Mono-n-methyl phthalate

Variable Name:
URXMNM
SAS Label:
Mono-n-methyl phthalate
English Text:
Mono-n-methyl phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.7 to 1170.3 Range of Values 2605 2605
. Missing 92 2697

URDMNMLC - Mono-n-methyl phthalate comment code

Variable Name:
URDMNMLC
SAS Label:
Mono-n-methyl phthalate comment code
English Text:
Mono-n-methyl phthalate 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 1497 1497
1 Below lower detection limit 1108 2605
. Missing 92 2697

URXMC1 - Mono-(3-carboxypropyl) phthalate

Variable Name:
URXMC1
SAS Label:
Mono-(3-carboxypropyl) phthalate
English Text:
Mono-(3-carboxypropyl) phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.1 to 389.1 Range of Values 2605 2605
. Missing 92 2697

URDMC1LC - Mono-(3-carboxypropyl) phthalate cmt

Variable Name:
URDMC1LC
SAS Label:
Mono-(3-carboxypropyl) phthalate cmt
English Text:
Mono-(3-carboxypropyl) phthalate 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 2569 2569
1 Below lower detection limit 36 2605
. Missing 92 2697

URXMHH - Mono-(2-ethyl-5-hydroxyhexyl) phthalate

Variable Name:
URXMHH
SAS Label:
Mono-(2-ethyl-5-hydroxyhexyl) phthalate
English Text:
Mono-(2-ethyl-5-hydroxyhexyl) phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.2 to 3141.4 Range of Values 2605 2605
. Missing 92 2697

URDMHHLC - Mono(2ethyl5hydroxyhexyl) phthalate cmt

Variable Name:
URDMHHLC
SAS Label:
Mono(2ethyl5hydroxyhexyl) phthalate cmt
English Text:
Mono-(2-ethyl-5-hydroxyhexyl) phthalate 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 2598 2598
1 Below lower detection limit 7 2605
. Missing 92 2697

URXMOH - Mono-(2-ethyl-5-oxohexl) phthalate

Variable Name:
URXMOH
SAS Label:
Mono-(2-ethyl-5-oxohexl) phthalate
English Text:
Mono-(2-ethyl-5-oxohexl) phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.4 to 1953.5 Range of Values 2605 2605
. Missing 92 2697

URDMOHLC - Mono-(2-ethyl-5-oxohexl) phthalate comnt

Variable Name:
URDMOHLC
SAS Label:
Mono-(2-ethyl-5-oxohexl) phthalate comnt
English Text:
Mono-(2-ethyl-5-oxohexyl) phthalate 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 2583 2583
1 Below lower detection limit 22 2605
. Missing 92 2697

URXMIB - Mono-isobutyl phthalate

Variable Name:
URXMIB
SAS Label:
Mono-isobutyl phthalate
English Text:
Mono-isobutyl phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.2 to 359.1 Range of Values 2605 2605
. Missing 92 2697

URDMIBLC - Mono-isobutyl phthalate comment code

Variable Name:
URDMIBLC
SAS Label:
Mono-isobutyl phthalate comment code
English Text:
Mono-isobutyl phthalate 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 2539 2539
1 Below lower detection limit 66 2605
. Missing 92 2697

URXECP - Mono-2-ethyl-5-carboxypentyl phthalate

Variable Name:
URXECP
SAS Label:
Mono-2-ethyl-5-carboxypentyl phthalate
English Text:
mono-2-ethyl-5-carboxypentyl phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.2 to 2886.9 Range of Values 2605 2605
. Missing 92 2697

URDECPLC - Mono-2-ethyl-5carboxypentyl phthalate cm

Variable Name:
URDECPLC
SAS Label:
Mono-2-ethyl-5carboxypentyl phthalate cm
English Text:
mono-2-ethyl-5-carboxypentyl phthalate 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 2604 2604
1 Below lower detection limit 1 2605
. Missing 92 2697

URXUCR - Creatinine, urine (mg/dL)

Variable Name:
URXUCR
SAS Label:
Creatinine, urine (mg/dL)
English Text:
Creatinine, urine (mg/dL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
9 to 882 Range of Values 2623 2623
. Missing 74 2697