Table of Contents

Locator Record

Title: Urinary Phthalates (PHTHTE_D )
Contact Number: 1-866-441-NCHS
Years of Content: 2005 - 2006
First Published: February, 2010
Revised: NA
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject: Urinary Phthalates
Record Source: NHANES 2005 - 2006
Survey Methodology: NHANES 2005 - 2006 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

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), mono(2-ethyl-5-carboxypentyl) phthalate (mECPP), monocarboxyoctyl phthalate (MCOP), and monocarboxynonyl phthalate (MCNP) (Kato et al., 2005; Silva et al., 2007) 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 of the phthalate metabolites. In addition, 4-methyl umbelliferone glucuronide is used to monitor deconjugation efficiency.  This selective method allows for rapid detection of monoester metabolites of commonly used phthalate diesters in human urine with limits of detection in the low ng/mL range.

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 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.  In cases, where the result was below the limit of detection, the value for that variable is the detection limit divided by the square root of two.  

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

The lower limit of detections for the environmental phthalates are

Lower Limit of Detections for the Environmental Phthalates
Analyte Item Id Limit of Detection(LLOD)
Mono(carboxyoctyl) phthalate URXCOP 0.7
Mono(carboxynonyl) phthalate URXCNP 0.6
Mono-2-ethyl-5-carboxypentyl phthalate URXECP 0.6
Mono-n-butyl phthalate (ng/mL) URXMBP 0.6
Mono-(3-carboxypropyl) phthalate (ng/mL) URXMC1 0.2
Mono-cyclohexyl Phthalate (ng/mL) URXMCP 0.603
Mono-ethyl phthalate (ng/mL) URXMEP 0.528
Mono-(2-ethyl-5-hydroxyhexyl) (ng/mL) URXMHH 0.7
Mono-(2-ethyl)-hexyl phthalate (ng/mL) URXMHP 1.2
Mono-isobutyl pthalate (ng/mL) URXMIB 0.3
Mono-n-methyl phthalate (ng/mL) URXMNM 1.1
Mono-isononyl phthalate (ng/mL) URXMNP 1.232
Mono-(2-ethyl-5-oxohexyl) (ng/mL) URXMOH 0.7
Mono-n-octyl phthalate (ng/mL) URXMOP 1.848
Mono-benzyl phthalate (ng/mL) URXMZP 0.216

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 - Environmental B Two-year weights

Variable Name:
WTSB2YR
SAS Label:
Environmental B Two-year weights
English Text:
Environmental B Two-year weights
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 486352.50255 Range of Values 2638 2638
. Missing 0 2638

URXCNP - Mono(carboxynonyl) phthalate (ng/mL)

Variable Name:
URXCNP
SAS Label:
Mono(carboxynonyl) phthalate (ng/mL)
English Text:
Mono(carboxynonyl) phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.42 to 672.6 Range of Values 2548 2548
. Missing 90 2638

URDCNPLC - Mono(carboxynonyl) phthalate comment

Variable Name:
URDCNPLC
SAS Label:
Mono(carboxynonyl) phthalate comment
English Text:
Mono(carboxynonyl) phthalate comment
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 2320 2320
1 Below lower detection limit 228 2548
. Missing 90 2638

URXCOP - Mono(carboxyoctyl) phthalate(ng/mL)

Variable Name:
URXCOP
SAS Label:
Mono(carboxyoctyl) phthalate(ng/mL)
English Text:
Mono(carboxyoctyl) phthalate(ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.49 to 4960.7 Range of Values 2548 2548
. Missing 90 2638

URDCOPLC - Mono(carboxyoctyl) phthalate comment

Variable Name:
URDCOPLC
SAS Label:
Mono(carboxyoctyl) phthalate comment
English Text:
Mono(carboxyoctyl) phthalate comment
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 2447 2447
1 Below lower detection limit 101 2548
. Missing 90 2638

URXMBP - Mono-n-butyl phthalate

Variable Name:
URXMBP
SAS Label:
Mono-n-butyl phthalate
English Text:
Mono-n-butyl phthalate
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.42 to 9873.6 Range of Values 2548 2548
. Missing 90 2638

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 2541 2541
1 Below lower detection limit 7 2548
. Missing 90 2638

URXMCP - Mono-cyclohexyl phthalate

Variable Name:
URXMCP
SAS Label:
Mono-cyclohexyl phthalate
English Text:
Mono-cyclohexyl phthalate
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.4264 to 30.552 Range of Values 2548 2548
. Missing 90 2638

URDMCPLC - Mono-cyclohexyl phthalate comment code

Variable Name:
URDMCPLC
SAS Label:
Mono-cyclohexyl phthalate comment code
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 54 54
1 Below lower detection limit 2494 2548
. Missing 90 2638

URXMEP - Mono-ethyl phthalate

Variable Name:
URXMEP
SAS Label:
Mono-ethyl phthalate
English Text:
Mono-ethyl phthalate
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.3734 to 20293.68 Range of Values 2548 2548
. Missing 90 2638

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 2542 2542
1 Below lower detection limit 6 2548
. Missing 90 2638

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

Variable Name:
URXMHP
SAS Label:
Mono-(2-ethyl)-hexyl phthalate
English Text:
Mono-(2-ethyl)-hexyl phthalate
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.85 to 1966.1 Range of Values 2548 2548
. Missing 90 2638

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
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 1753 1753
1 Below lower detection limit 795 2548
. Missing 90 2638

URXMNP - Mono-isononyl phthalate

Variable Name:
URXMNP
SAS Label:
Mono-isononyl phthalate
English Text:
Mono-isononyl phthalate
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.8712 to 228.074 Range of Values 2548 2548
. Missing 90 2638

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 349 349
1 Below lower detection limit 2199 2548
. Missing 90 2638

URXMOP - Mono-n-octyl phthalate

Variable Name:
URXMOP
SAS Label:
Mono-n-octyl phthalate
English Text:
Mono-n-octyl phthalate
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.3067 to 14.784 Range of Values 2548 2548
. Missing 90 2638

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 29 29
1 Below lower detection limit 2519 2548
. Missing 90 2638

URXMZP - Mono-benzyl phthalate

Variable Name:
URXMZP
SAS Label:
Mono-benzyl phthalate
English Text:
Mono-benzyl phthalate
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.1527 to 16510.32 Range of Values 2548 2548
. Missing 90 2638

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 2519 2519
1 Below lower detection limit 29 2548
. Missing 90 2638

URXMNM - Mono-n-methyl phthalate

Variable Name:
URXMNM
SAS Label:
Mono-n-methyl phthalate
English Text:
Mono-n-methyl phthalate
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.78 to 901.5 Range of Values 2548 2548
. Missing 90 2638

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 1040 1040
1 Below lower detection limit 1508 2548
. Missing 90 2638

URXMC1 - Mono-(3-carboxypropyl) phthalate

Variable Name:
URXMC1
SAS Label:
Mono-(3-carboxypropyl) phthalate
English Text:
Mono-(3-carboxypropyl) phthalate
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.14 to 299.2 Range of Values 2548 2548
. Missing 90 2638

URDMC1LC - Mono-(3-carboxypropyl) phthalate cmt

Variable Name:
URDMC1LC
SAS Label:
Mono-(3-carboxypropyl) phthalate cmt
English Text:
Mono-(3-carboxypropyl) phthalate cmt
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 2469 2469
1 Below lower detection limit 79 2548
. Missing 90 2638

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
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.49 to 7438.1 Range of Values 2548 2548
. Missing 90 2638

URDMHHLC - Mono(2ethyl5hydroxyhexyl) phthalate cmt

Variable Name:
URDMHHLC
SAS Label:
Mono(2ethyl5hydroxyhexyl) phthalate cmt
English Text:
Mono(2ethyl5hydroxyhexyl) phthalate cmt
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 2538 2538
1 Below lower detection limit 10 2548
. Missing 90 2638

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

Variable Name:
URXMOH
SAS Label:
Mono-(2-ethyl-5-oxohexyl) phthalate
English Text:
Mono-(2-ethyl-5-oxohexyl) phthalate
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.49 to 4743.3 Range of Values 2548 2548
. Missing 90 2638

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-oxohexl) phthalate comnt
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 2522 2522
1 Below lower detection limit 26 2548
. Missing 90 2638

URXMIB - Mono-isobutyl pthalate

Variable Name:
URXMIB
SAS Label:
Mono-isobutyl pthalate
English Text:
Mono-isobutyl pthalate
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.21 to 14537 Range of Values 2548 2548
. Missing 90 2638

URDMIBLC - Mono-isobutyl pthalate comment code

Variable Name:
URDMIBLC
SAS Label:
Mono-isobutyl pthalate comment code
English Text:
Mono-isobutyl pthalate 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 2495 2495
1 Below lower detection limit 53 2548
. Missing 90 2638

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
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.42 to 7782.6 Range of Values 2548 2548
. Missing 90 2638

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

Variable Name:
URDECPLC
SAS Label:
Mono-2ethyl-5-carboxypentyl 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 2547 2547
1 Below lower detection limit 1 2548
. Missing 90 2638

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
5 to 608 Range of Values 2565 2565
. Missing 73 2638