Table of Contents

Component Description

 Both the lab data and questionnaire items will be released in this file.  

Volatile Organic Compound Questions:
The volatile organic compound section of the Mobile Examination Center (MEC) Interview and Phlebotomy Component (PH) provide personal interview data.

Trihalomethanes  (Home Tap Water):
In addition to assessing levels of VOCs in blood, VOC levels were measured in home tap water specimens provided by NHANES participants. Specifically, trihalomethanes (THMs) and the fuel additive methyl tertiary-butyl ether (MTBE) are measured in these samples.

Eligible Sample

Participants aged 12 years and older on a one-half sample had questions administered and water specimens tested.

Description of Laboratory Methodology

Measurements of Trihalomethanes (THMs) and MTBE in Tap Water:
This automated analytical method uses headspace solid-phase microextraction (SPME) coupled with capillary gas chromatography and mass spectrometry (Cardinali et al. 2004). This method quantitated trace levels of THMs (chloroform, bromodichloromethane, dibromochloromethane, and bromoform) and MTBE in tap water. Detection limits of less than 0.15 ng/mL for all analytes and linear ranges of three orders of magnitude are adequate for measuring the THMs in tap water samples tested from across the United States. THMs are stable for extended periods in tap water samples after quenching of residual chlorine and buffering to pH 6.5, thus enabling larger epidemiologic field studies with simplified sample collection protocols.

 

Laboratory Quality Assurance and Monitoring

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 contract laboratories. In the MEC, these methods include performing second examinations on previously examined participants and blind split samples collected on “dry run” sessions.

NCHS developed and distributed a quality control protocol for all the contract laboratories which outlined the Westgard rules used 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 and Westat quarterly. The reports are reviewed for trends or shifts in the data. The laboratories are required to explain any identified areas of concern.

Analytic Notes

Subsample Weights
Trihalomethanes (THMs) and MTBE were obtained in survey participants aged 12 years and older from a one-half sample. 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.

Links to NHANES Data Files
Measures of volatile organic compounds in blood and water were assessed in a subsample of participants aged 12 years and older. Use the special weights (WTSVOC2Y) included in this data file when analyzing data. Please refer to the Analytic Guidelines for further details on the use of sample weights and other analytic issues.

Variance Estimation
The analysis of NHANES laboratory data must be conducted with the key survey design and basic demographic variables. The recommended procedure for variance estimation requires use of stratum and PSU variables (SDMVSTRA and SDMVPSU, respectively), which are included in the demographic data file for each data release. The NHANES Household Questionnaire and Demographic Data Files contain demographic data, health indicators, and other related information collected during household interviews. The phlebotomy file includes auxiliary information such as the conditions precluding venipuncture. The demographic, household questionnaire and phlebotomy files may be linked to the laboratory data file using the unique survey participant identifier SEQN.

Detection limits
The detection limit was variable for many of the analytes in the data set. In addition two variables are provided for each of these analytes. The variable named LBD___LC indicates whether the result was below the limit of detection. There are three values: “0”, “1”, and “2”. “0” means that the result was at or above the limit of detection. “1” indicates that the result was below the limit of detection. “2” means the result was above the limit of detection and exceeds calibrated range of assay.

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

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 12 YEARS - 150 YEARS

WTSVOC2Y - VOC Subsample Weight

Variable Name:
WTSVOC2Y
SAS Label:
VOC Subsample Weight
English Text:
VOC Subsample Weight
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7544.8236215 to 319733.44187 Range of Values 3374 3374
. Missing 41 3415

LBXWBF - Water Bromoform (ng/mL)

Variable Name:
LBXWBF
SAS Label:
Water Bromoform (ng/mL)
English Text:
Water Bromoform (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0707 to 60 Range of Values 3172 3172
. Missing 243 3415

LBDWBFLC - Water Bromoform Comment Code

Variable Name:
LBDWBFLC
SAS Label:
Water Bromoform Comment Code
English Text:
Water Bromoform Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 2072 2072
1 below detectable limit 1100 3172
2 detectable result and exceeds the calibrated range of assay 0 3172
. Missing 243 3415

LBXWBM - Water Bromodichloromethane (ng/mL)

Variable Name:
LBXWBM
SAS Label:
Water Bromodichloromethane (ng/mL)
English Text:
Water Bromodichloromethane (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0354 to 51.2 Range of Values 3172 3172
. Missing 243 3415

LBDWBMLC - Water Bromodichloromethane Comment Code

Variable Name:
LBDWBMLC
SAS Label:
Water Bromodichloromethane Comment Code
English Text:
Water Bromodichloromethane Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 2835 2835
1 below detectable limit 337 3172
2 detectable result and exceeds the calibrated range of assay 0 3172
. Missing 243 3415

LBXWCF - Water Chloroform (ng/mL)

Variable Name:
LBXWCF
SAS Label:
Water Chloroform (ng/mL)
English Text:
Water Chloroform (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0849 to 109 Range of Values 3121 3121
. Missing 294 3415

LBDWCFLC - Water Chloroform Comment Code

Variable Name:
LBDWCFLC
SAS Label:
Water Chloroform Comment Code
English Text:
Water Chloroform Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 2742 2742
1 below detectable limit 379 3121
2 detectable result and exceeds the calibrated range of assay 0 3121
. Missing 294 3415

LBXWCM - Water Dibromochloromethane (ng/mL)

Variable Name:
LBXWCM
SAS Label:
Water Dibromochloromethane (ng/mL)
English Text:
Water Dibromochloromethane (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0707 to 67 Range of Values 3172 3172
. Missing 243 3415

LBDWCMLC - Water Dibromochloromethane Comment Code

Variable Name:
LBDWCMLC
SAS Label:
Water Dibromochloromethane Comment Code
English Text:
Water Dibromochloromethane Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 2826 2826
1 below detectable limit 346 3172
2 detectable result and exceeds the calibrated range of assay 0 3172
. Missing 243 3415

LBXWME - Water MTBE (ng/mL)

Variable Name:
LBXWME
SAS Label:
Water MTBE (ng/mL)
English Text:
Water MTBE (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0707 to 10.7 Range of Values 3177 3177
. Missing 238 3415

LBDWMELC - Water MTBE Comment Code

Variable Name:
LBDWMELC
SAS Label:
Water MTBE Comment Code
English Text:
Water MTBE Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 39 39
1 below detectable limit 3138 3177
2 detectable result and exceeds the calibrated range of assay 0 3177
. Missing 238 3415

VTQ200A - Store paint/fuels in home, bsmnt, garage

Variable Name:
VTQ200A
SAS Label:
Store paint/fuels in home, bsmnt, garage
English Text:
{Do you/Does she/Does he} store paints or fuels inside {your/her/his} home? Include {your/her/his} basement {and attached garage}.
English Instructions:
CAPI INSTRUCTION: IF SP HAS AN ATTACHED GARAGE (CODED ' 1' IN VTQ.210), DISPLAY {and attached garage}.
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 1066 1066
2 No 2039 3105
7 Refused 0 3105
9 Don't know 13 3118
. Missing 297 3415

VTQ210 - Attached garage?

Variable Name:
VTQ210
SAS Label:
Attached garage?
English Text:
I would like to ask you a few questions about {your/SP's} home. Does {your/her/his} home have an attached garage?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 1099 1099
2 No 2020 3119
7 Refused 0 3119
9 Don't know 0 3119
. Missing 296 3415

VTQ220 - Private well?

Variable Name:
VTQ220
SAS Label:
Private well?
English Text:
Is the source of water for {your/her/his} home from a private well?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 363 363
2 No 2740 3103
7 Refused 0 3103
9 Don't know 16 3119
. Missing 296 3415

VTQ230A - Toilet bowl deodorizers

Variable Name:
VTQ230A
SAS Label:
Toilet bowl deodorizers
English Text:
{Do you/Does she/Does he} use toilet bowl deodorizers inside {your/her/his} home?
English Instructions:
HELP SCREEN SHOULD READ: Some toilet bowl deodorizers clip onto the toilet rim, other, such as deodorant blocks and gels, are placed inside the tank or hang inside the wall of the tank. Brand names include Bully, 2000 Flushes, Vanish, X-14, Ty-D-Bol, Toilet Duck, Clorox, Lime-A-Way, and Sno Bol.
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 1380 1380
2 No 1714 3094
7 Refused 0 3094
9 Don't know 24 3118
. Missing 297 3415

VTQ230B - Moth balls or crystals?

Variable Name:
VTQ230B
SAS Label:
Moth balls or crystals?
English Text:
{Do you/Does she/Does he} use moth balls or crystals inside {your/her/his} home?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 281 281
2 No 2817 3098
7 Refused 0 3098
9 Don't know 20 3118
. Missing 297 3415

VTQ240A - Pump gas into a car or motor vehicle?

Variable Name:
VTQ240A
SAS Label:
Pump gas into a car or motor vehicle?
English Text:
Now I am going to ask you a few questions about {your/SP's} activities over the last three days. This means today, yesterday, or the day before yesterday. In the last three days, did {you/she/he} pump gas into a car or other motor vehicle {yourself/herself/himself}?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 1193 1193
2 No 1925 3118 VTQ250a
7 Refused 0 3118 VTQ250a
9 Don't know 0 3118 VTQ250a
. Missing 297 3415

VTQ240B - How long ago did you pump gas?

Variable Name:
VTQ240B
SAS Label:
How long ago did you pump gas?
English Text:
How long ago, in hours, did {you/she/he} pump gas into a car?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 to 72 Range of Values 1193 1193
777 Refused 0 1193
999 Don't know 0 1193
. Missing 2222 3415

VTQ250A - Spend time at swimming pool?

Variable Name:
VTQ250A
SAS Label:
Spend time at swimming pool?
English Text:
In the last three days, did {you/she/he} spend any time at a swimming pool, in a hot tub, or in a steam room?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 108 108
2 No 3010 3118 VTQ260a
7 Refused 0 3118 VTQ260a
9 Don't know 0 3118 VTQ260a
. Missing 297 3415

VTQ250B - How long ago at swimming pool?

Variable Name:
VTQ250B
SAS Label:
How long ago at swimming pool?
English Text:
How long ago, in hours, has it been since {you/she/he} spent time in a swimming pool, in a hot tub, or in a steam room?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 to 72 Range of Values 107 107
777 Refused 0 107
999 Don't know 1 108
. Missing 3307 3415

VTQ260A - Visit a dry cleaning shop?

Variable Name:
VTQ260A
SAS Label:
Visit a dry cleaning shop?
English Text:
In the last three days, did {you/she/he} visit a dry cleaning shop or wear clothes that had been dry-cleaned within the last week?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 182 182
2 No 2936 3118
7 Refused 0 3118
9 Don't know 0 3118
. Missing 297 3415

VTQ260B - Spend 10 minutes near cigarette smoke?

Variable Name:
VTQ260B
SAS Label:
Spend 10 minutes near cigarette smoke?
English Text:
In the last three days, did {you/she/he} spend 10 or more minutes near a person who was smoking a cigarette, cigar, or pipe?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 1157 1157
2 No 1960 3117
7 Refused 0 3117
9 Don't know 1 3118
. Missing 297 3415

VTQ270A - Take a hot shower?

Variable Name:
VTQ270A
SAS Label:
Take a hot shower?
English Text:
In the last three days, did {you/she/he} take a hot shower or bath for five minutes or longer?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 2662 2662
2 No 455 3117 VTQ280a
7 Refused 0 3117 VTQ280a
9 Don't know 1 3118 VTQ280a
. Missing 297 3415

VTQ270B - How long since hot shower?

Variable Name:
VTQ270B
SAS Label:
How long since hot shower?
English Text:
How long ago, in hours, has it been since {your/SP's} last shower or hot bath?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 to 72 Range of Values 2661 2661
777 Refused 0 2661
999 Don't know 1 2662
. Missing 753 3415

VTQ280A - Breathe fumes from paints?

Variable Name:
VTQ280A
SAS Label:
Breathe fumes from paints?
English Text:
In the last three days, did {you/she/he} breathe fumes from any of the following: Paints?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 205 205
2 No 2913 3118
7 Refused 0 3118
9 Don't know 0 3118
. Missing 297 3415

VTQ280B - Breathe fumes from degreasing cleaners?

Variable Name:
VTQ280B
SAS Label:
Breathe fumes from degreasing cleaners?
English Text:
[In the last three days, did {you/she/he} breathe fumes from any of the following:] Degreasing cleaners?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 230 230
2 No 2886 3116
7 Refused 0 3116
9 Don't know 2 3118
. Missing 297 3415

VTQ280C - Breathe fumes from diesel fuel?

Variable Name:
VTQ280C
SAS Label:
Breathe fumes from diesel fuel?
English Text:
[In the last three days, did {you/she/he} breathe fumes from any of the following:] Diesel fuel or kerosene?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 258 258
2 No 2860 3118
7 Refused 0 3118
9 Don't know 0 3118
. Missing 297 3415

VTQ280D - Breathe fumes from paint thinner?

Variable Name:
VTQ280D
SAS Label:
Breathe fumes from paint thinner?
English Text:
[In the last three days, did {you/she/he} breathe fumes from any of the following:] Paint thinner, brush cleaner, or furniture stripper?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 103 103
2 No 3015 3118
7 Refused 0 3118
9 Don't know 0 3118
. Missing 297 3415

VTQ280E - Breathe fumes from drycleaning fluid?

Variable Name:
VTQ280E
SAS Label:
Breathe fumes from drycleaning fluid?
English Text:
[In the last three days, did {you/she/he} breathe fumes from any of the following:] Drycleaning fluid or spot remover?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 99 99
2 No 3018 3117
7 Refused 0 3117
9 Don't know 1 3118
. Missing 297 3415

VTQ280F - Breathe fumes from fingernail polish?

Variable Name:
VTQ280F
SAS Label:
Breathe fumes from fingernail polish?
English Text:
[In the last three days, did {you/she/he} breathe fumes from any of the following:] Fingernail polish or fingernail polish remover?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 475 475
2 No 2643 3118
7 Refused 0 3118
9 Don't know 0 3118
. Missing 297 3415

VTQ280G - Breathe fumes from glue?

Variable Name:
VTQ280G
SAS Label:
Breathe fumes from glue?
English Text:
[In the last three days, did {you/she/he} breathe fumes from any of the following:] Glues or adhesives used for hobbies or crafts?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 142 142
2 No 2976 3118
7 Refused 0 3118
9 Don't know 0 3118
. Missing 297 3415

VTQ280H - Breathe fumes from varnish?

Variable Name:
VTQ280H
SAS Label:
Breathe fumes from varnish?
English Text:
[In the last three days, did {you/she/he} breathe fumes from any of the following:] Varnish or stain?
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 58 58
2 No 3060 3118
7 Refused 0 3118
9 Don't know 0 3118
. Missing 297 3415