Table of Contents

Component Description

The 24-Hour Urine Collection component was added to NHANES in 2014 to: 1) estimate dietary intakes of sodium and potassium; 2) estimate the excretion of microalbumin (albumin and creatinine); and 3) assess measures of kidney markers (phosphorus, magnesium, calcium, oxalate, and urea nitrogen), phytoestrogen, caffeine, volatile organic compounds, and iodine in the U.S. population.

In 2014, a random half sample of non-pregnant participants aged 20-69 years and examined in the mobile examination center (MEC) were asked to collect their urines for a 24-hour period. For the first half of the year, a random half of those who completed the initial 24-hour urine collection were recruited to collect a second 24-hour urine specimen 3 to 10 days later. For the second half of the year, all those who completed the first 24-hour urine collection were recruited to collect a second 24-hour urine specimen. Data processing information from the initial and second 24-hour urine collections was released in two separate datasets (U1_H_R and U2_H_R). Each of these two files contains information on the following: total urine volume, length of collection, completeness of the urine collection, number of complete urine specimens, collection day of the week, and responses to questions on the participants’ experience collecting the urine to assess completeness of the specimen. Please see the documentation for these two files for more details.

Separate datasets were produced to include laboratory results of analytes from the 24-hour urine collections. The present file contains analyte data for urinary perchlorate, nitrate & thiocyanate. See Appendix I for the list of data files for the 24-hour urine collection.

Urinary Perchlorate

Perchlorate has been used as an oxidant in solid fuel propellants for rockets and missiles since the 1950s. Lesser amounts of perchlorate are used in matches and fireworks. Perchlorate can also form naturally in the environment and can accumulate in nitrate-rich mineral deposits mined for use in fertilizers. Drinking water, milk, and certain plants with high water content (e.g., lettuce) can be the main sources of perchlorate intake for humans. Perchlorate has been used medically to treat hyperthyroidism. Its inhibitory effect on thyroid hormone production has led to concerns that exposure even to low levels of perchlorate in the environment might affect vulnerable groups, such as pregnant women with inadequate iodine intake and infants for whom thyroid hormone levels must be maintained adequately for normal brain development. Perchlorate taken into the body is rapidly eliminated in the urine, within a matter of hours. Measurement of urinary perchlorate is useful to assess recent human exposure.

Urinary Nitrate and Thiocyanate

Nitrate and thiocyanate are polyatomic anions that can disrupt thyroid function by competitively inhibiting iodide uptake, similar to the action of perchlorate. Nitrate, thiocyanate, and perchlorate can reversibly bind to the sodium-iodide symporter (NIS) protein resulting in reduced iodine absorption by the thyroid. Nitrate, thiocyanate and perchlorate interact additively to impair iodide uptake by the thyroid. Therefore, assessment of the impact of perchlorate exposure on thyroid function should include assessment of nitrate and thiocyanate exposure. By assessing exposure to each of the three physiologically relevant NIS-inhibitors, the relative impact of each chemical on thyroid function can be estimated and appropriate regulatory action taken if exposures are negatively impacting thyroid hormone levels. Impaired thyroid function can lead to hypothyroidism, proliferative thyroid lesions, and impaired neurodevelopment in infants.

Nitrate poisoning can also lead to methemoglobinemia, primarily in infants. The prevalence of nitrate exposure is likely due to nitrate intake from both food and drinking water, with foods (e.g., vegetables, milk, dairy products) thought to account for the majority of nitrate intake for typical American adults. Nitrate anion can also form endogenously. Public health prevention efforts have reduced the prevalence of methemoglobinemia in the United States. A reference range for urinary nitrate will provide useful information relevant to nitrate poisoning and subclinical methemoglobinemia in the U.S.

Thiocyanate is also a biomarker of cyanide exposure from tobacco smoke or diet. Thiocyanate primarily forms in the body as a metabolite of cyanide from tobacco smoke or cyanogenic foods, such as cassava. Exposure to toxic levels of cyanide can result from numerous chemical reactions. Lower levels of thiocyanate can also be found in milk, dairy products, and some vegetables. Therefore, a defined reference range for thiocyanate will provide useful benchmark data in case of a cyanide exposure event.

To reduce the risk of inadvertent disclosure, all data from this 1-year 24-hour urine collection can only be accessed through the NCHS Research Data Center (RDC). Instructions for requesting use of these data are available from the RDC website (https://www.cdc.gov/rdc/).

Eligible Sample

The eligible sample was a random one-half sample of all examined participants aged 20-69 years with a few participants eliminated based on exclusion criteria (e.g., pregnant). For the first half of the year, a random half of those who completed the initial 24-hour urine collection were recruited to collect a second 24-hour urine specimen 3 to 10 days later. For the second half of the year, all those who completed the first 24-hour urine collection were recruited to collect a second 24-hour urine specimen.

Description of Laboratory Methodology

This method is a quantitative procedure for the measurement of nitrate, perchlorate, and thiocyanate in human urine using ion chromatography coupled with electrospray tandem mass spectrometry. Chromatographic separation is achieved using an IonPac AS16 column with sodium hydroxide as the eluent. The eluent from the column is ionized using an electrospray interface to generate and transmit negative ions into the mass spectrometer. Comparison of relative response factors (ratio of native analyte to stable isotope labeled internal standard) with known standard concentrations yields individual analyte concentrations.

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

This is a new component in the 2014 survey cycle.

Laboratory Method Files

Urinary Perchlorate, Nitrate, and Thiocyanate Laboratory Procedure Manual (July 2020)

Laboratory Quality Assurance and Monitoring

Urine samples were 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 24-Hour Urine Study Procedures Manual. Vials were stored under appropriate frozen (-30°C) conditions until they were shipped to the 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 Laboratory Procedures Manual (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 QC 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 during “dry run” sessions. In addition, contract laboratories randomly perform repeat testing on 2% of all specimens.

NCHS developed and distributed a QC 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 Sciences’ QA/QC 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

Variables with data from 24-hour urine first collection and second collection specimens are denoted with a “UR1” and “UR2” prefix, respectively.

Refer to the 2013-2014 Laboratory Data Overview for general information on NHANES laboratory data.

There are over 800 laboratory tests performed on NHANES participants. However, not all participants provided biospecimens or enough volume for all the tests to be performed. The specimen availability can also vary by age or other population characteristics. Analysts should evaluate the extent of missing data in the dataset related to the outcome of interest as well as any predictor variables used in the analyses to determine whether additional re-weighting for item non-response is necessary.

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.

Subsample weights

NHANES participants were selected on the basis of a national probability design. In order to increase the number of participants for specific demographic groups, a multi-stage, unequal probability of selection design was implemented. In 2014, the sample design included an oversample of certain demographic groups: persons 80 years and older, non-Hispanic black, non-Hispanic Asian, Hispanic, and low income white and other persons. Sample weights are constructed that encompass the unequal probabilities of selection, as well as adjustments for non-participation by selected sample persons. In order to produce national, representative estimates, the appropriate sample weights must be used.

The 24-hour urine collection was conducted in a random one-half subsample of 1,103 persons 20-69 years examined in the mobile examination center in 2014. A special one-year urine sample weight (WT1YUR) is provided for the 827 participants who provided a complete 24-hour urine specimen to obtain representative national estimates based on this first 24-hour urine collection. As with other NHANES subsamples, the 24-hour urine sample weights account for the additional probability of selection into the subsample component as well as the additional nonresponse. This sample weight, along with strata (VSTRA) and PSUs (VPSU) are used to calculate variance estimates based on the Taylor Series Linearization method. In addition, 16 Fay-adjusted balanced repeated replication (Fay’s BRR) weights (WT1YUB01 – WT1YUB16), along with their corresponding strata (VSTRABRR) and PSUs (VPSUBRR), and 15 Jackknife replicate weights (WT1YUR01 – WT1YUR15) that can be used with VSTRA and VPSU are included in the files to obtain variance estimates based on a replication method. The Fay’s BRR weights were created with an adjustment factor of 0.3. There is no separate sample weight provided for use with the data collected for the second 24-hour urine specimen. These data were collected for the purpose of estimating within-person variability and not for obtaining nationally representative estimates based on the second 24-hour urine sample. New sample weights would need to be calculated by the user if any additional analytical efforts were planned for the second collection 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 2013-2014 Demographics File contains demographic data, health indicators, and other related information collected during household interviews as well as 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.

Please see Appendix 1 for the list of data files produced from the 24-hour urine collection.

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 all of the analytes in the data set. Two variables are provided for each of these analytes. The variable name ending in “1LC” (ex., URDUP8LC) 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., URDUP8LC=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 UR2 (ex., UR2UP8) provides the analytic result for that analyte.

The lower limit of detection (LLOD in ng/mL) for 24-Hour Urinary Perchlorate, Nitrate, and Thiocyanate –First and Second Collections:

Variable Name

Analyte

LLOD

UR1UP8

Perchlorate, urine - 1st Collection (ng/mL)

0.05

UR1NO3

Nitrate, urine - 1st Collection (ng/mL)

700

UR1SCN

Thiocyanate, urine - 1st Collection (ng/mL)

20

UR2UP8

Perchlorate, urine – 2nd Collection (ng/mL)

0.05

UR2NO3

Nitrate, urine - 2nd Collection (ng/mL)

700

UR2SCN

Thiocyanate, urine - 2nd Collection (ng/mL)

20

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 20 YEARS - 69 YEARS

UR2UCSTS - Urine collection status

Variable Name:
UR2UCSTS
SAS Label:
Urine collection status
English Text:
Urine collection status
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Complete specimen 436 436
2 Incomplete specimen 19 455
3 Agreed but no specimen returned 26 481
4 Refused urine collection 43 524
5 No time to schedule, end of stand 61 585
6 Not sampled for second urine collection 518 1103
. Missing 0 1103

UR2UP8 - Perchlorate, urine - 2nd Collect (ng/mL)

Variable Name:
UR2UP8
SAS Label:
Perchlorate, urine - 2nd Collect (ng/mL)
English Text:
Perchlorate, urine - 2nd Collection (ng/mL)
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.181 to 59.1 Range of Values 434 434
. Missing 669 1103

UR2NO3 - Nitrate, urine - 2nd Collection (ng/mL)

Variable Name:
UR2NO3
SAS Label:
Nitrate, urine - 2nd Collection (ng/mL)
English Text:
Nitrate, urine - 2nd Collection (ng/mL)
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
495 to 1260000 Range of Values 434 434
. Missing 669 1103

URDNO2LC - Nitrate - 2nd Collection Comt Code

Variable Name:
URDNO2LC
SAS Label:
Nitrate - 2nd Collection Comt Code
English Text:
Nitrate, urine - 2nd Collection Comment Code
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 430 430
1 Below lower detection limit 4 434
. Missing 669 1103

UR2SCN - Thiocyanate, urine - 2nd Collect (ng/mL)

Variable Name:
UR2SCN
SAS Label:
Thiocyanate, urine - 2nd Collect (ng/mL)
English Text:
Thiocyanate, urine - 2nd Collection (ng/mL)
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
41.7 to 29000 Range of Values 434 434
. Missing 669 1103

UR2CR - Creatinine, urine 2nd Collection (mg/dL)

Variable Name:
UR2CR
SAS Label:
Creatinine, urine 2nd Collection (mg/dL)
English Text:
Creatinine, urine 2nd Collection (mg/dL)
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
13 to 351 Range of Values 436 436
. Missing 667 1103

VPSU - Variance PSU

Variable Name:
VPSU
SAS Label:
Variance PSU
English Text:
Variance primary sampling unit (PSU)
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 to 15 Range of Values 1103 1103
. Missing 0 1103

VSTRA - Variance stratum

Variable Name:
VSTRA
SAS Label:
Variance stratum
English Text:
Variance stratum
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 1 1103 1103
. Missing 0 1103

WT1YUR - 1 year urine weight

Variable Name:
WT1YUR
SAS Label:
1 year urine weight
English Text:
1 year urine weight
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
26626.969653 to 1039861.6547 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUR01 - 1 year urine weight - Jackknife 01

Variable Name:
WT1YUR01
SAS Label:
1 year urine weight - Jackknife 01
English Text:
1 year urine weight: Jackknife replicate weight 01
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
32988.435668 to 1087823.4451 Range of Values 775 775
0 Not in replicate sample or no complete urine collection 328 1103
. Missing 0 1103

WT1YUR02 - 1 year urine weight - Jackknife 02

Variable Name:
WT1YUR02
SAS Label:
1 year urine weight - Jackknife 02
English Text:
1 year urine weight: Jackknife replicate weight 02
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
30811.629073 to 1108478.079 Range of Values 757 757
0 Not in replicate sample or no complete urine collection 346 1103
. Missing 0 1103

WT1YUR03 - 1 year urine weight - Jackknife 03

Variable Name:
WT1YUR03
SAS Label:
1 year urine weight - Jackknife 03
English Text:
1 year urine weight: Jackknife replicate weight 03
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
32444.744583 to 1124054.7132 Range of Values 760 760
0 Not in replicate sample or no complete urine collection 343 1103
. Missing 0 1103

WT1YUR04 - 1 year urine weight - Jackknife 04

Variable Name:
WT1YUR04
SAS Label:
1 year urine weight - Jackknife 04
English Text:
1 year urine weight: Jackknife replicate weight 04
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
30122.038208 to 1088100.7098 Range of Values 748 748
0 Not in replicate sample or no complete urine collection 355 1103
. Missing 0 1103

WT1YUR05 - 1 year urine weight - Jackknife 05

Variable Name:
WT1YUR05
SAS Label:
1 year urine weight - Jackknife 05
English Text:
1 year urine weight: Jackknife replicate weight 05
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
26595.342712 to 1386604.9599 Range of Values 764 764
0 Not in replicate sample or no complete urine collection 339 1103
. Missing 0 1103

WT1YUR06 - 1 year urine weight - Jackknife 06

Variable Name:
WT1YUR06
SAS Label:
1 year urine weight - Jackknife 06
English Text:
1 year urine weight: Jackknife replicate weight 06
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
25525.240772 to 1185899.8756 Range of Values 779 779
0 Not in replicate sample or no complete urine collection 324 1103
. Missing 0 1103

WT1YUR07 - 1 year urine weight - Jackknife 07

Variable Name:
WT1YUR07
SAS Label:
1 year urine weight - Jackknife 07
English Text:
1 year urine weight: Jackknife replicate weight 07
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
29254.953947 to 1238634.2445 Range of Values 751 751
0 Not in replicate sample or no complete urine collection 352 1103
. Missing 0 1103

WT1YUR08 - 1 year urine weight - Jackknife 08

Variable Name:
WT1YUR08
SAS Label:
1 year urine weight - Jackknife 08
English Text:
1 year urine weight: Jackknife replicate weight 08
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
27922.235179 to 994400.70164 Range of Values 787 787
0 Not in replicate sample or no complete urine collection 316 1103
. Missing 0 1103

WT1YUR09 - 1 year urine weight - Jackknife 09

Variable Name:
WT1YUR09
SAS Label:
1 year urine weight - Jackknife 09
English Text:
1 year urine weight: Jackknife replicate weight 09
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
27354.825857 to 1046225.3276 Range of Values 778 778
0 Not in replicate sample or no complete urine collection 325 1103
. Missing 0 1103

WT1YUR10 - 1 year urine weight - Jackknife 10

Variable Name:
WT1YUR10
SAS Label:
1 year urine weight - Jackknife 10
English Text:
1 year urine weight: Jackknife replicate weight 10
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
26787.826959 to 1085325.7097 Range of Values 776 776
0 Not in replicate sample or no complete urine collection 327 1103
. Missing 0 1103

WT1YUR11 - 1 year urine weight - Jackknife 11

Variable Name:
WT1YUR11
SAS Label:
1 year urine weight - Jackknife 11
English Text:
1 year urine weight: Jackknife replicate weight 11
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
28902.632671 to 1039358.8672 Range of Values 792 792
0 Not in replicate sample or no complete urine collection 311 1103
. Missing 0 1103

WT1YUR12 - 1 year urine weight - Jackknife 12

Variable Name:
WT1YUR12
SAS Label:
1 year urine weight - Jackknife 12
English Text:
1 year urine weight: Jackknife replicate weight 12
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
28817.414878 to 1276503.1858 Range of Values 771 771
0 Not in replicate sample or no complete urine collection 332 1103
. Missing 0 1103

WT1YUR13 - 1 year urine weight - Jackknife 13

Variable Name:
WT1YUR13
SAS Label:
1 year urine weight - Jackknife 13
English Text:
1 year urine weight: Jackknife replicate weight 13
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
30806.914324 to 1126511.0723 Range of Values 779 779
0 Not in replicate sample or no complete urine collection 324 1103
. Missing 0 1103

WT1YUR14 - 1 year urine weight - Jackknife 14

Variable Name:
WT1YUR14
SAS Label:
1 year urine weight - Jackknife 14
English Text:
1 year urine weight: Jackknife replicate weight 14
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
28423.967242 to 1136146.2984 Range of Values 767 767
0 Not in replicate sample or no complete urine collection 336 1103
. Missing 0 1103

WT1YUR15 - 1 year urine weight - Jackknife 15

Variable Name:
WT1YUR15
SAS Label:
1 year urine weight - Jackknife 15
English Text:
1 year urine weight: Jackknife replicate weight 15
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
29944.843186 to 1053222.6222 Range of Values 794 794
0 Not in replicate sample or no complete urine collection 309 1103
. Missing 0 1103

VPSUBRR - Variance PSU for BRR

Variable Name:
VPSUBRR
SAS Label:
Variance PSU for BRR
English Text:
Variance PSU for use with BRR weights
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 to 2 Range of Values 827 827
. Missing 276 1103

VSTRABRR - Variance stratum for BRR

Variable Name:
VSTRABRR
SAS Label:
Variance stratum for BRR
English Text:
Variance stratum for use with BRR weights
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 1 1103 1103
. Missing 0 1103

WT1YUB01 - 1 year urine weight - Fay's BRR 01

Variable Name:
WT1YUB01
SAS Label:
1 year urine weight - Fay's BRR 01
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 01
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
9708.117363 to 1993228.0013 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB02 - 1 year urine weight - Fay's BRR 02

Variable Name:
WT1YUB02
SAS Label:
1 year urine weight - Fay's BRR 02
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 02
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
8349.837846 to 1606031.1301 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB03 - 1 year urine weight - Fay's BRR 03

Variable Name:
WT1YUB03
SAS Label:
1 year urine weight - Fay's BRR 03
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 03
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
9901.051122 to 1842177.1645 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB04 - 1 year urine weight - Fay's BRR 04

Variable Name:
WT1YUB04
SAS Label:
1 year urine weight - Fay's BRR 04
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 04
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7565.591177 to 1701923.7682 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB05 - 1 year urine weight - Fay's BRR 05

Variable Name:
WT1YUB05
SAS Label:
1 year urine weight - Fay's BRR 05
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 05
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
8593.837633 to 1729983.0084 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB06 - 1 year urine weight - Fay's BRR 06

Variable Name:
WT1YUB06
SAS Label:
1 year urine weight - Fay's BRR 06
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 06
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7080.034439 to 1837031.7658 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB07 - 1 year urine weight - Fay's BRR 07

Variable Name:
WT1YUB07
SAS Label:
1 year urine weight - Fay's BRR 07
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 07
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
9349.310683 to 1769525.1682 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB08 - 1 year urine weight - Fay's BRR 08

Variable Name:
WT1YUB08
SAS Label:
1 year urine weight - Fay's BRR 08
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 08
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
8094.557196 to 1663257.4171 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB09 - 1 year urine weight - Fay's BRR 09

Variable Name:
WT1YUB09
SAS Label:
1 year urine weight - Fay's BRR 09
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 09
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
9247.466513 to 1825840.209 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB10 - 1 year urine weight - Fay's BRR 10

Variable Name:
WT1YUB10
SAS Label:
1 year urine weight - Fay's BRR 10
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 10
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7819.636741 to 1625507.9938 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB11 - 1 year urine weight - Fay's BRR 11

Variable Name:
WT1YUB11
SAS Label:
1 year urine weight - Fay's BRR 11
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 11
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
10596.04009 to 1661523.21 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB12 - 1 year urine weight - Fay's BRR 12

Variable Name:
WT1YUB12
SAS Label:
1 year urine weight - Fay's BRR 12
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 12
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
9613.933744 to 1699918.537 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB13 - 1 year urine weight - Fay's BRR 13

Variable Name:
WT1YUB13
SAS Label:
1 year urine weight - Fay's BRR 13
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 13
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
9982.528076 to 1491089.5334 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB14 - 1 year urine weight - Fay's BRR 14

Variable Name:
WT1YUB14
SAS Label:
1 year urine weight - Fay's BRR 14
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 14
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
8619.090806 to 1978559.1055 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB15 - 1 year urine weight - Fay's BRR 15

Variable Name:
WT1YUB15
SAS Label:
1 year urine weight - Fay's BRR 15
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 15
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
12595.358001 to 1688513.1145 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

WT1YUB16 - 1 year urine weight - Fay's BRR 16

Variable Name:
WT1YUB16
SAS Label:
1 year urine weight - Fay's BRR 16
English Text:
1 year urine weight: Fay's adjusted balanced repeated replication (Fay's BRR) weight 16
Target:
Both males and females 20 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
8365.095245 to 1734825.4197 Range of Values 827 827
0 No complete urine collection 276 1103
. Missing 0 1103

Appendix 1

Data Files for the 24-hour Urine Collection

First 24-Hour Urine Collection

Second 24-Hour Urine Collection

Data Processing – First Collection (UR1_H_R)

Data Processing – Second Collection (UR2_H_R)

Kidney Markers – First Collection (U1KM_H_R)

Kidney Markers – Second Collection (U2KM_H_R)

Electrolytes – First Collection (U1LT_H_R)

Electrolytes – Second Collection (U2LT_H_R)

Iodine - First Collection (U1IO_H_R)

Iodine - Second Collection (U2IO_H_R)

Perchlorate, Nitrate, and Thiocyanate - First Collection (U1PN_H_R)

Perchlorate, Nitrate, and Thiocyanate - Second Collection (U2PN_H_R)

Phytoestrogens and Caffeine - First Collection (U1PT_H_R)

Phytoestrogens and Caffeine - Second Collection (U2PT_H_R)