Table of Contents

Component Description

Urinary aromatic diamines can be formed from the metabolism of diisocyanates, which are widely used in the polymer industry, particularly in the production of polyurethane-based consumer products (e.g., foam cushions, mattresses, pillows, and car seats), elastomers, coating, and adhesives (Lockey, J. E., et. al, 2015).

Diisocyanates may be released into the environment through industrial waste, and volatilization and degradation of consumer products. Exposure to diisocyanates can occur through dermal contact, ingestion, and inhalation. All diisocyanates are classified as skin and respiratory sensitizers (Lockey, J. E., et. al, 2015; Timchalk, C., et. al, 1994). Exposure to these chemicals can be lethal when inhaled at high concentrations by sensitized subjects, can elicit hypersensitivity pneumonitis and accelerated lung function loss, and is considered one of the most frequently reported causes of occupational asthma (Lockey, J. E., et. al, 2015; Dykewicz, M. S., 2009; Merget, R., et. al, 2002). In addition, the in vivo hydrolyzed product of diisocyanates (i.e., diamines such as 4,4'-Diaminodiphenylmethane (4MDA), 2,4-Diaminotoluene (4TDA), 2,6-Diaminotoluene (6TDA), 1,5-Diaminonaphthalene (5NDA), and p-phenylenediamine (PPDA)) have been reported as hepatotoxic and carcinogenic in human and animal models (Timchalk, C., et. al, 1994; Report on Carcinogens, 13th ed.; IARC, 1999; McGill, D.B., et. al, 1974).

Eligible Sample

All examined participants aged 3 to 5 years were eligible and participants aged 6 years and older from a one-third subsample were eligible.

Description of Laboratory Methodology

This method is a quantitative procedure for the measurement of urinary aromatic diamines using ultra performance liquid chromatography coupled with atmospheric pressure chemical ionization tandem mass spectrometry (UPLC-APCI-MS/MS). Prior to chromatographic separation, urine samples are hydrolyzed in 0.6 M hydrochloric acid at 80 °C for 4 hours. Hydrolyzed samples are passed through solid phase extraction (SPE) sorbents. Chromatographic separation is achieved using a reversed phase column with 5 mM ammonium acetate buffer at pH 9.2 (mobile phase A) and 5/95% 100 mM ammonium acetate buffer/acetonitrile (mobile phase B). The eluent from the column is ionized using an APCI interface to generate and transmit positive ions into the mass spectrometer.

Refer to the Laboratory Method Files section for a detailed description of the laboratory methods used.

This is a new component in the 2015-2016 survey cycle.

Laboratory Method Files

Aromatic Diamines Laboratory Procedure Manual (October 2018)

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, Atlanta, GA 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.

The NHANES quality assurance and quality control (QA/QC) protocols meet the 1988 Clinical Laboratory Improvement Act mandates. Detailed QA/QC instructions are discussed in the NHANES LPM.

Mobile Examination Centers (MECs)

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

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% of all specimens.

NCHS developed and distributed a quality control protocol for all CDC and contract laboratories which outlined the use of Westgard rules (Westgard et al., 1981) 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 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 Services’ quality control and quality assurance performance criteria for accuracy and precision, similar to the Westgard rules (Caudill et al., 2008).

Data Processing and Editing

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

Analytic Notes

Refer to the 2015-2016 Laboratory Data Overview for general information on NHANES laboratory data.

Subsample Weights

Aromatic diamines in urine were measured in a full sample of participants ages 3-5 and a one-third subsample of participants aged 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.

Demographic and Other Related Variables

The analysis of NHANES laboratory data must be conducted using the appropriate survey design and demographic variables. The NHANES 2015-2016 Demographics File contains demographic data, health indicators, and other related information collected during household interviews as well as the 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.

This laboratory data file can be linked to the other NHANES data files using the unique survey participant identifier (i.e., SEQN).

Detection Limits

The detection limits were constant for the analytes in the data set. Two variables are provided for each of these analytes. The variable named ending in “LC” (ex., URDAAMLC) 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., URDAAMLC=1), an imputed fill value was placed in the analyte results field. This value is the lower limit of detection divided by the square root of 2 (LLOD/sqrt [2]). The other variable prefixed URX (ex., URXAAM) provides the analytic result for the analyte.

The lower limit of detection (LLOD, in ng/mL) for urinary aromatic diamines:

Variable Name

SAS Label

LLOD

URX4TDA

2,4-Diaminotoluene (4TDA) (ng/mL)

0.640

URX6TDA

2,6-Diaminotoluene (6TDA) (ng/mL)

0.640

URX4MDA

4,4'-Diaminodiphenylmethane (4MDA) (ng/mL)

0.048

URX5NDA

1,5-Diaminonaphthalene (5NDA) (ng/mL)

1.00

URXPPDA

p-Phenylenediamine (PPDA) (ng/mL)

2.00

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 3 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 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
6552.119284 to 708844.24678 Range of Values 3231 3231
0 Participants 6+ years with no lab specimen 48 3279
. Missing 0 3279

URX4TDA - 2,4-Diaminotoluene (4TDA) (ng/mL)

Variable Name:
URX4TDA
SAS Label:
2,4-Diaminotoluene (4TDA) (ng/mL)
English Text:
2,4-Diaminotoluene (4TDA) (ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Hard Edits:
0.0000 to 999.99
Code or Value Value Description Count Cumulative Skip to Item
0.453 to 48.8 Range of Values 2595 2595
. Missing 684 3279

URD4DALC - 2,4-Diaminotoluene (4TDA) Comment Code

Variable Name:
URD4DALC
SAS Label:
2,4-Diaminotoluene (4TDA) Comment Code
English Text:
2,4-Diaminotoluene (4TDA) Comment Code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 176 176
1 Below lower detection limit 2419 2595
. Missing 684 3279

URX6TDA - 2,6-Diaminotoluene (6TDA) (ng/mL)

Variable Name:
URX6TDA
SAS Label:
2,6-Diaminotoluene (6TDA) (ng/mL)
English Text:
2,6-Diaminotoluene (6TDA) (ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Hard Edits:
0.0000 to 999.99
Code or Value Value Description Count Cumulative Skip to Item
0.453 to 16.6 Range of Values 2430 2430
. Missing 849 3279

URD6DALC - 2,6-Diaminotoluene (6TDA) Comment Code

Variable Name:
URD6DALC
SAS Label:
2,6-Diaminotoluene (6TDA) Comment Code
English Text:
2,6-Diaminotoluene (6TDA) Comment Code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 46 46
1 Below lower detection limit 2384 2430
. Missing 849 3279

URX4MDA - 4MDA (ng/mL)

Variable Name:
URX4MDA
SAS Label:
4MDA (ng/mL)
English Text:
4,4'-Diaminodiphenylmethane (4MDA) (ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Hard Edits:
0.0000 to 999.99
Code or Value Value Description Count Cumulative Skip to Item
0.034 to 18.8 Range of Values 2831 2831
. Missing 448 3279

URD4MALC - 4MDA Comment Code

Variable Name:
URD4MALC
SAS Label:
4MDA Comment Code
English Text:
4,4'-Diaminodiphenylmethane (4MDA) Comment Code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 1584 1584
1 Below lower detection limit 1247 2831
. Missing 448 3279

URX5NDA - 1,5-Diaminonaphthalene (5NDA) (ng/mL)

Variable Name:
URX5NDA
SAS Label:
1,5-Diaminonaphthalene (5NDA) (ng/mL)
English Text:
1,5-Diaminonaphthalene (5NDA) (ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Hard Edits:
0.0000 to 999.99
Code or Value Value Description Count Cumulative Skip to Item
0.71 to 3.68 Range of Values 2758 2758
. Missing 521 3279

URD5NALC - 5NDA Comment Code

Variable Name:
URD5NALC
SAS Label:
5NDA Comment Code
English Text:
1,5-Diaminonaphthalene (5NDA) Comment Code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 3 3
1 Below lower detection limit 2755 2758
. Missing 521 3279

URXPPDA - p-Phenylenediamine (PPDA) (ng/mL)

Variable Name:
URXPPDA
SAS Label:
p-Phenylenediamine (PPDA) (ng/mL)
English Text:
p-Phenylenediamine (PPDA) (ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Hard Edits:
0.0000 to 999.99
Code or Value Value Description Count Cumulative Skip to Item
1.41 to 282 Range of Values 2608 2608
. Missing 671 3279

URDPDALC - p-Phenylenediamine (PPDA) Comment Code

Variable Name:
URDPDALC
SAS Label:
p-Phenylenediamine (PPDA) Comment Code
English Text:
p-Phenylenediamine (PPDA) Comment Code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 310 310
1 Below lower detection limit 2298 2608
. Missing 671 3279