Table of Contents

Component Description

Dibutyl phthalates, including di-n-butyl phthalate (DBP) and di-isobutyl phthalate (DiBP), are used as plasticizers for polymers contained in consumer products, such as adhesives and cosmetics (Hubinger 2010;Hubinger and Havery 2006). Since 2001, at CDC, we have measured mono-n-butyl phthalate (MBP) and mono-isobutyl phthalate (MiBP) to assess exposure to DBP and DiBP, respectively. We recently modified the original analytical method used at CDC for measuring phthalate metabolites, so we could include two oxidative metabolites of DBP and DiBP, mono-3-hydroxy-n-butyl phthalate (MHBP) and mono-2-hydroxy-iso-butyl phthalate (MHiBP), from NHANES 2013-2014.

Eligible Sample

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

Description of Laboratory Methodology

MHBP and MHiBP were measured with on-line solid phase extraction coupled to isotope dilution-high performance liquid chromatography tandem mass spectrometry (Silva et al. 2013).

Laboratory Method Files

Laboratory Quality Assurance and Monitoring

The analytical measurements were conducted following strict quality control/quality assurance CLIA guidelines. Along with the study samples, each analytical run included high- and low-concentration quality control materials (QCs) and reagent blanks to assure the accuracy and reliability of the data. The concentrations of the high-concentration QCs and the low-concentration QCs, averaged to obtain one measurement of high-concentration QC and low-concentration QC for each run, were evaluated using standard statistical probability rules (Caudill et al. 2008).

Data Processing and Editing

Data were received after all analyses were complete. The data were not edited.

Data Access: All data are publicly available.

Analytic Notes

Detection Limits

The detection limits were constant for all of the analytes in the data set. Two variables are provided for each analyte. The variable name ending in “L” (ex., SDUMHBPL) indicates whether the result was below the limit of detection: the value “0” means that the result was at or above the limit of detection, “1” indicates that the result was below the limit of detection. For analytes with analytic results below the lower limit of detection (ex., SDUMHBPL=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). The other variable prefixed SS (ex., SSURMHBP) provides the analytic result for that analyte.

The lower limit of detection (LLOD, in ng/mL) for MHBP and MHiBP is:

VARIABLE SAS LABEL LLOD
 SSURMHBP  Mono-3-hydroxy-n-butyl phthalate (ng/mL)  0.4
 SSURHIBP  Mono-2-hydroxy-iso-butyl phthalate (ng/mL)  0.4

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

WTSB2YR - Environmental B 2-year weights

Variable Name:
WTSB2YR
SAS Label:
Environmental B 2-year weights
English Text:
Environmental B 2-year weights
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
14988.396826 to 482310.7883 Range of Values 2682 2682
. Missing 0 2682

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
8 to 659 Range of Values 2680 2680
. Missing 2 2682

SSURMHBP - Mono-3-hydroxy-n-butyl phthalate (ng/mL)

Variable Name:
SSURMHBP
SAS Label:
Mono-3-hydroxy-n-butyl phthalate (ng/mL)
English Text:
Mono-3-hydroxy-n-butyl phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.28 to 96.2 Range of Values 2681 2681
. Missing 1 2682

SDUMHBPL - Mono-3-hydroxy-n-butyl phthalate cmt

Variable Name:
SDUMHBPL
SAS Label:
Mono-3-hydroxy-n-butyl phthalate cmt
English Text:
Mono-3-hydroxy-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 1959 1959
1 Below lower detection limit 722 2681
. Missing 1 2682

SSURHIBP - Mono-2-hydroxy-iso-butyl phthlte (ng/mL)

Variable Name:
SSURHIBP
SAS Label:
Mono-2-hydroxy-iso-butyl phthlte (ng/mL)
English Text:
Mono-2-hydroxy-iso-butyl phthalate (ng/mL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.28 to 143.3 Range of Values 2681 2681
. Missing 1 2682

SDUHIBPL - Mono-2-hydroxy-iso-butyl phthlte cmt

Variable Name:
SDUHIBPL
SAS Label:
Mono-2-hydroxy-iso-butyl phthlte cmt
English Text:
Mono-2-hydroxy-iso-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 2520 2520
1 Below lower detection limit 161 2681
. Missing 1 2682