Table of Contents

Component Description

Pyrethroid pesticides are synthetic analogues of pyrethrins, used to control a range of insects in residential, commercial and agricultural settings, and they may be applied on animals to control insect infestation. Pyrethroid insecticides are among the most common active ingredients in commercially available insect sprays and are also used as structural termiticides. Permethrin is used in skin lotions and shampoos as a medical treatment for lice and scabies. Pyrethroid insecticides do not persist in the environment because they are rapidly degraded within days to months. Human metabolism of pyrethroids occurs rapidly, and metabolites are eliminated in urine and bile over several days. Two of the urinary metabolites measured are unique to specific pyrethroids: 4-fluoro-3-phenoxyacetic acid from cyfluthrin and cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid from deltamethrin. The other urinary metabolites can result from exposure to any of several pyrethroid insecticides. Because pyrethroid insecticides are widely used in the U.S. population, measuring urinary pyrethroid metabolites is important to evaluate human exposure and potential for health effects.

Of the two herbicides measured in urine, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), only 2,4-D is currently registered for use in the U.S. 2,4-D is widely used to control broadleaf weeds in residential, agricultural, and aquatic environments. It degrades in soil over days to weeks and is rarely detected in ground waters. 2,4-D is not metabolized by humans and is eliminated unchanged and rapidly in the urine. Because 2,4-D is widely used in the U.S., measuring urinary 2,4-D is important to evaluate human exposure and potential for health effects.

The specific organophosphorus insecticides with urinary metabolites measured are chlorpyrifos and chlorpyrifos-methyl (3,5,6-trichloro-2-pyridinol or TCPy), diazinon (2,-isopropyl-4-methyl-6-hydroxypyrimidine or IMPY), malathion (malathion dicarboxylic acid or MDA), and methyl and ethyl parathion (para-nitrophenol or PNP). Chlorpyrifos and malathion are widely used in residential and agricultural insect control, and chlorpyrifos-methyl and diazinon are restricted to agricultural applications only. Methyl parathion has extremely limited agricultural use, and ethyl parathion is no longer registered for use in the U.S. Each of these measured urinary metabolites can also result from environmental degradation of the parent organophosphorus insecticide. Human metabolism of these organophosphorus insecticides results in the specific metabolites named above, dialkylphosphate metabolites, and other metabolites, all which are eliminated in urine over a few days. Detecting any of these urinary metabolites in a person’s urine may indicate exposure to the specific organophosphorus insecticide or to the environmental breakdown product or both. Because several of these insecticides are widely used in the U.S., measuring these urinary organophosphate insecticide metabolites is important to evaluate human exposure and potential for health effects.

Eligible Sample

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

Description of Laboratory Methodology

The approach followed is a modification of previous methodology (Beeson et al. 1999; Olsson et al. 2004). The target analytes are extracted and concentrated from the urine matrix using an automated solid phase extraction system. Selective separation of the analytes is achieved using high-performance liquid chromatography with a gradient elution program. Sensitive detection of the analytes is performed by a triple quadrupole mass spectrometer with a heated electrospray ionization source (Davis et al. 2013). Analytes are identified using the specific m/z ion transition, the retention time and the ion ratio of the quantification and confirmation m/z ion transitions. Isotopically labeled internal standards are used for precise and accurate quantification. This method can be used to assess human exposure to select non-persistent pesticides by measuring their metabolites in urine. It does not directly test for any disease.

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

Subsample weights

Measures of urinary Pyrethroids, Herbicides, and OP Metabolites 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 2003-2004 data files using the unique survey participant identifier SEQN.

Detection Limits

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 detection limit divided by the square root of 2 is the value that is provided for results that are below the limit of detection.

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

WTSC2YR - Two-year MEC weights of subsample C

Variable Name:
WTSC2YR
SAS Label:
Two-year MEC weights of subsample C
English Text:
Two-year MEC weights of subsample C
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 520135.04901 Range of Values 2694 2694
. Missing 0 2694

URX24D - 2,4-D (ug/L) result

Variable Name:
URX24D
SAS Label:
2,4-D (ug/L) result
English Text:
2,4-D (ug/L) result
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.28 to 349.72 Range of Values 2587 2587
. Missing 107 2694

URD24DLC - 2,4-D comment code

Variable Name:
URD24DLC
SAS Label:
2,4-D comment code
English Text:
2,4-D 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 1030 1030
1 Below lower detection limit 1557 2587
. Missing 107 2694

URX25T - 2,4,5-Trichlorophenoxyacetic acid (ug/L)

Variable Name:
URX25T
SAS Label:
2,4,5-Trichlorophenoxyacetic acid (ug/L)
English Text:
2,4,5-Trichlorophenoxyacetic acid (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.07 to 3.42 Range of Values 2588 2588
. Missing 106 2694

URD25TLC - 2,4,5-Trichlorophenoxyacetic acid comt

Variable Name:
URD25TLC
SAS Label:
2,4,5-Trichlorophenoxyacetic acid comt
English Text:
2,4,5-Trichlorophenoxyacetic acid 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 12 12
1 Below lower detection limit 2576 2588
. Missing 106 2694

URX4FP - 4-fluoro-3-phenoxybenzoic (ug/L) acid

Variable Name:
URX4FP
SAS Label:
4-fluoro-3-phenoxybenzoic (ug/L) acid
English Text:
4-fluoro-3-phenoxybenzoic (ug/L) acid
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.07 to 7.72 Range of Values 2588 2588
. Missing 106 2694

URD4FPLC - Fluoro-phenoxybenzoic acid code

Variable Name:
URD4FPLC
SAS Label:
Fluoro-phenoxybenzoic acid code
English Text:
4-fluoro-3-phenoxybenzoic acid 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 170 170
1 Below lower detection limit 2418 2588
. Missing 106 2694

URXCB3 - Dibromovinyl-dimeth prop carboacid(ug/L)

Variable Name:
URXCB3
SAS Label:
Dibromovinyl-dimeth prop carboacid(ug/L)
English Text:
cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.35 to 4.8 Range of Values 2583 2583
. Missing 111 2694

URDCB3LC - Dibromovinyl-dimeth prop carboacid code

Variable Name:
URDCB3LC
SAS Label:
Dibromovinyl-dimeth prop carboacid code
English Text:
cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid 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 38 38
1 Below lower detection limit 2545 2583
. Missing 111 2694

URXCPM - 3,5,6-trichloropyridinol (ug/L) result

Variable Name:
URXCPM
SAS Label:
3,5,6-trichloropyridinol (ug/L) result
English Text:
3,5,6-trichloropyridinol (ug/L) result
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.07 to 98.15 Range of Values 2588 2588
. Missing 106 2694

URDCPMLC - 3,5,6-trichloropyridinol comment code

Variable Name:
URDCPMLC
SAS Label:
3,5,6-trichloropyridinol comment code
English Text:
3,5,6-trichloropyridinol 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 2482 2482
1 Below lower detection limit 106 2588
. Missing 106 2694

URXMAL - Malathion diacid (ug/L) result

Variable Name:
URXMAL
SAS Label:
Malathion diacid (ug/L) result
English Text:
Malathion diacid (ug/L) result
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.35 to 38.35 Range of Values 2581 2581
. Missing 113 2694

URDMALLC - Malathion diacid comment code

Variable Name:
URDMALLC
SAS Label:
Malathion diacid comment code
English Text:
Malathion diacid 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 531 531
1 Below lower detection limit 2050 2581
. Missing 113 2694

URXOPM - 3-phenoxybenzoic (ug/L) acid result

Variable Name:
URXOPM
SAS Label:
3-phenoxybenzoic (ug/L) acid result
English Text:
3-phenoxybenzoic (ug/L) acid result
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.07 to 57.62 Range of Values 2454 2454
. Missing 240 2694

URDOPMLC - 3-phenoxybenzoic acid comment code

Variable Name:
URDOPMLC
SAS Label:
3-phenoxybenzoic acid comment code
English Text:
3-phenoxybenzoic acid comment cod
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 1689 1689
1 Below lower detection limit 765 2454
. Missing 240 2694

URXOXY - Oxypyrimidine (ug/L) result

Variable Name:
URXOXY
SAS Label:
Oxypyrimidine (ug/L) result
English Text:
Oxypyrimidine (ug/L) result
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.07 to 14.37 Range of Values 2588 2588
. Missing 106 2694

URDOXYLC - Oxypyrimidine comment code

Variable Name:
URDOXYLC
SAS Label:
Oxypyrimidine comment code
English Text:
Oxypyrimidine 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 670 670
1 Below lower detection limit 1918 2588
. Missing 106 2694

URXPAR - Paranitrophenol (ug/L) result

Variable Name:
URXPAR
SAS Label:
Paranitrophenol (ug/L) result
English Text:
Paranitrophenol (ug/L) result
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.07 to 39.67 Range of Values 2564 2564
. Missing 130 2694

URDPARLC - Paranitrophenol comment code

Variable Name:
URDPARLC
SAS Label:
Paranitrophenol comment code
English Text:
Paranitrophenol 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 2373 2373
1 Below lower detection limit 191 2564
. Missing 130 2694

URXTCC - Dichlorovnl-dimeth prop carboacid(ug/L)

Variable Name:
URXTCC
SAS Label:
Dichlorovnl-dimeth prop carboacid(ug/L)
English Text:
trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.42 to 73.93 Range of Values 2576 2576
. Missing 118 2694

URDTCCLC - Dichlorovnl-dimeth prop carboacid code

Variable Name:
URDTCCLC
SAS Label:
Dichlorovnl-dimeth prop carboacid code
English Text:
trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid 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 411 411
1 Below lower detection limit 2165 2576
. Missing 118 2694

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
3 to 724 Range of Values 2596 2596
. Missing 98 2694