National Health and Nutrition Examination Survey

2005 - 2006 Data Documentation, Codebook, and Frequencies

Volatile Organic Compounds in Blood (VOCWB_D)

Data File: VOCWB_D.xpt

First Published: December, 2011

Last Revised: NA

Locator Record

Title: Volatile Organic Compounds in Blood (VOCWB_D )
Contact Number: 1-866-441-NCHS
Years of Content: 2005 - 2006
First Published: December, 2011
Revised: NA
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject:Volatile Organic Compounds in Blood and Related Questionnaire Items
Record Source: NHANES 2005 - 2006
Survey Methodology: NHANES 2005 - 2006 is a stratified multistage probability sample of the civilian non-institutionalized population of the U.S.
Medium: NHANES Web site; SAS transport files

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.  

Volatile Organic Compounds (Human Blood):

Volatile organic compounds (VOCs) are a large group of chemicals that have been used as solvents, degreasers, and cleaning agents in industry and consumer products. Many of the VOCs were found to contaminate ground water and drinking water sources, and because of human health concerns, have been banned or restricted from most uses. 

The halogenated solvents are VOCs consisting of a hydrocarbon chain or one hydrocarbon substituted with one or more chlorine or bromine atoms. Most of these chemicals are used as degreasers and solvents in various products such as paints. In the past, 1,1,1-trichloroethane was used as a dry cleaning agent, insect fumigant, and solvent in consumer products; methylene chloride, perchloroethylene, and trichloroethene are other VOCs that were widely used in the past.

Methyl-tert-butyl ether (MTBE) was used as an additive to replace lead in gasoline, but its use was banned after widespread ground water contamination was discovered. Benzene, toluene, ethylbenzene, xylene, and  styrene, collectively referred to as BTEXS, are components of tobacco smoke and along with 2,5-dimethyl furan, these VOCs are usually detected in blood of cigarette smokers at higher levels than in non-smokers. Chlorobenzene (monochlorobenzene) and the three dichlorobenzenes are halogenated aromatic hydrocarbons pirmarily used in industrial and chemical synthetic processes. Chlorobenzene has been used to produce DDT, phenol, and nitrobenzene. The dichlorobenzenes are also chemical intermediates in synthesis of dyes, pesticides, and other industrial products. 1,4-Dichlorobenzene (para-dichlorobenzene) is used also as a moth repellent and as a deodorizer. Disinfection by-products (DBP) including bromodichloromethane, dibromochloromethane, bromoform, and chloroform are formed when chlorine interacts with natural organic materials found in water. Primary sources of DBPs are chlorinated drinking water and recreational water bodies, such as swimming pools.

Inhalation is the most common VOC exposure route for the general population, including indoor sources from such as paints, adhesives, cleaning solutions, and aerosolized insecticide sprays; from industries producing these solvents; and from contaminated waste disposal sites. Drinking water may contribute to exposure when underground drinking water supplies are contaminated. After they are absorbed in the body, VOCs are rapidly eliminated in exhaled breath or may be rapidly metabolized and eliminated in the urine.

Eligible Sample

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

Description of Laboratory Methodology

Interview Setting and Mode of Administration

The questions were asked during the physical examination, in the mobile examination center (MEC). The questions were administered by the phlebotomist or the MEC interviewers.

Data Processing and Editing

Automated data collection procedures for the survey were introduced in NHANES 2003–2004. In the MECs and analytical laboratories, data for the laboratory component are recorded directly onto a computerized data collection form. The system is centrally integrated, and it allows for ongoing monitoring of much of the data. Although the complete blood count and pregnancy analyses are performed in the MEC laboratory, most analyses are conducted elsewhere by approximately 21 laboratories across the United States.

Guidelines have been developed that provide standards for naming variables, filling missing values, and handling missing records. NCHS staff, assisted by contract staff, has developed data-editing specifications that check data sets for valid codes, ranges, and skip-pattern consistencies and examine the consistency of values between interrelated variables. Comments have been reviewed and recoded. NCHS staff verifies extremely high and low values whenever possible, and numerous consistency checks are performed. Nonetheless, users should examine the range and frequency of values before analyzing data.

Data Editing

The data editing specifications are as follows:

• Age and gender checks
• Total number of observations complete for each field
• No field overlap, truncated values, or atypical results
• Direct data entry errors
• Abnormal results confirmed by lab
• Test algorithm performed
• Checked comment codes to resolve missing results and missing records
• All missing results and missing MEC-examined records are accounted
• Duplicate records were verified and deleted

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 Westgaard 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

Measures of volatile organic compounds in blood and water were assessed in a subsample of participants aged 20 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.

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 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,  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 two 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.

 

Lower Limits of Detection

Analyte	Lower Limit of Detecction
Blood 2,5-Dimethylfuran (ng/mL)"	0.011
Blood 1,1-Dichloroethane (ng/mL	0.01
Blood 1,2-Dichlorobenzene (ng/mL)	0.1
Blood 1,1-Dichloroethene (ng/mL)"	0.009
Blood 1,2-Dichloroethane (ng/mL	0.01
Blood cis-1,2-Dichloroethene (ng/mL)	0.01
Blood 1,1,2-Trichloroethene (ng/mL)"	0.01
Blood 1,2-Dibromo-3-chloropropane(ng/mL	0.1
Blood trans-1,2-Dichloroethene (ng/mL	0.01
Blood 1,3-Dichlorobenzene (ng/mL	0.05
Blood Tetrachloroethene (ng/mL	0.048
Blood 1,1,2,2-Tetrachloroethane (ng/mL)"	0.01
Blood Bromoform (pg/mL	1.5
Blood Bromodichloromethane (pg/mL	0.62
Blood Benzene (ng/mL)	0.024
Blood Chlorobenzene (ng/mL	0.011
Blood Chloroform (pg/mL	2.1
Blood Dibromochloromethane (pg/mL	0.62
Blood Carbon Tetrachloride (ng/mL	0.05
Blood 1,4-Dichlorobenzene (ng/mL	0.12
Blood Dibromomethane (ng/mL	0.03
Blood 1,2-Dichloropropane (ng/mL	0.008
Blood Ethylbenzene (ng/mL	0.024
Blood Hexachloroethane (ng/mL	0.011
Blood Methylene Chloride (ng/mL	0.07
Blood Methylene Chloride (ng/mL	0.25
Blood MTBE (pg/mL	1.4
Blood Nitrobenezene (ng/mL	0.3
Blood o-Xylene (ng/mL	0.024
Blood Styrene (ng/mL	0.03
Blood Trichloroethene (ng/mL	0.012
Blood Toluene (ng/mL	0.025
1,1,1-Trichloroethane	0.01
1,1,1-Trichloroethane	0.05
Blood m-/p-Xylene (ng/mL	0.034

References

• Blount BC, Kobelski RJ, McElprang DO, Ashley DL, Morrow JC, Chambers DM, Cardinali FL (2006) Quantification of 31 Volatile Organic Compounds in Whole Blood Using Solid-Phase Microextraction and Gas Chromatography/Mass Spectrometry. J. Chromatography B. 832(2):292-301.
• Bonin MA, Silva LK, Smith MM, Ashley DL, Blount BC (2005) Measurement of trihalomethanes and methyl tert-butyl ether in whole blood using gas chromatography with high-resolution mass spectrometry. J Anal Toxicol. 29(2):81-89.
• Cardinali FL, Ashley DL, Morrow JC, Moll DM, Blount BC (2004), Measurement of Trihalomethanes and Methyl Tertiary-Butyl Ether in Tap Water Using Solid-Phase Microextraction GC/MS, Journal of Chromatographic Sciences, 42:200-206.
• Morandi MT, Stock TH. Personal Exposures to Toxic Air Pollutants, Vol. 2. Houston, TX; The University of Texas – Houston, Health Science Center, School of Public Health: 1998.
• U.S. Occupational Safety and Health Administration (OSHA). Organic Vapors, Method 07 in Analytical Methods Manual. Salt Lake City, Utah; OSHA Analytical Laboratory: 1985.

Codebook and Frequencies