• Component Description
• Eligible Sample
• Description of Laboratory Methodology
• Data Processing and Editing
• Laboratory Quality Assurance and Monitoring
• Analytic Notes
• Codebook
  • SEQN - Respondent sequence number
  • LBXATC - a-Tocopherol(ug/dL)
  • LBDATCSI - a-Tocopherol(umol/L)
  • LBXALC - a-Carotene(ug/dL)
  • LBDALCSI - a-Carotene(umol/L)
  • LBXACY - a-Cryptoxanthin(ug/dL)
  • LBDACYSI - a-Cryptoxanthin(umol/L)
  • LBXBEC - trans-b-carotene(ug/dL)
  • LBDBECSI - trans-b-carotene(umol/L)
  • LBXBCC - total b-Carotene(ug/dL)
  • LBDBCCSI - total b-Carotene(umol/L)
  • LBXCBC - cis-b-carotene(ug/dL)
  • LBDCBCSI - cis-b-carotene(umol/L)
  • LBXCLC - cis-Lycopene(ug/dL)
  • LBDCLCSI - cis-Lycopene(umol/L)
  • LBXCLZ - cis- Lutein/Zeaxanthin(ug/dL)
  • LBDCLZSI - cis- Lutein/Zeaxanthin(umol/L)
  • LBXCRY - b-cryptoxanthin(ug/dL)
  • LBDCRYSI - b-cryptoxanthin(umol/L)
  • LBXDTC - d-Tocopherol(ug/dL)
  • LBDDTCSI - d-Tocopherol(umol/L)
  • LBXGTC - g-tocopherol(ug/dL)
  • LBDGTCSI - g-tocopherol(umol/L)
  • LBXLCC - total Lycopene(ug/dL)
  • LBDLCCSI - total Lycopene(umol/L)
  • LBXLUT - Lutein(ug/dL)
  • LBDLUTSI - Lutein(umol/L)
  • LBXLUZ - Combined Lutein/zeaxanthin (ug/dL)
  • LBDLUZSI - Combined Lutein/zeaxanthin (umol/L)
  • LBXLYC - trans-lycopene(ug/dL)
  • LBDLYCSI - trans-lycopene(umol/L)
  • LBXPHF - Phytofluene(ug/dL)
  • LBDPHFSI - Phytofluene(umol/L)
  • LBXPHE - Phytoene(ug/dL)
  • LBDPHESI - Phytoene(umol/L)
  • LBXRPL - Retinyl palmitate(ug/dL)
  • LBDRPLSI - Retinyl palmitate(umol/L)
  • LBXRST - Retinyl stearate(ug/dL)
  • LBDRSTSI - Retinyl stearate(umol/L)
  • LBXVIA - Retinol(ug/dL)
  • LBDVIASI - Retinol(umol/L)
  • LBXZEA - Zeaxanthin(ug/dL)
  • LBDZEASI - Zeaxanthin(umol/L)

National Health and Nutrition Examination Survey

2003-2004 Data Documentation, Codebook, and Frequencies

Vitamin A, Vitamin E & Carotenoids (L45VIT_C)

Data File: L45VIT_C.xpt

First Published: October 2007

Last Revised: NA

Component Description

The objectives of this component are:

1. to provide data for monitoring secular trends in measures of nutritional status in the U.S. population;
2. to evaluate the effect of people’s habits and behaviors such as physical activity and the use of alcohol, tobacco, and dietary supplements on people’s nutritional status; and
3. to evaluate the effect of changes in nutrition and public health policies including welfare reform legislation, food fortification policy, and child nutrition programs on the nutritional status of the U.S. population.

These data will be used to estimate deficiencies and toxicities of specific nutrients in the population and subgroups, to provide population reference data, and to estimate the contribution of diet, supplements, and other factors to serum levels of nutrients. Data will be used for research to further define nutrient requirements as well as optimal levels for disease prevention and health promotion.

Eligible Sample

Participants aged 6 years and older who do not meet any of the exclusion criteria are eligible.

Description of Laboratory Methodology

Vitamin A, Vitamin E, and Carotenoids

Serum concentrations of vitamin A (retinol, retinyl palmitate, retinyl stearate), vitamin E (α-, δ-, and γ-tocopherols), and twelve carotenoids (lutein, zeaxanthin, α-cryptoxanthin, β-cryptoxanthin, trans-lycopene,cis-lycopene, α-carotene, trans-β-carotene, cis-β-carotene, ciscombined lutein/zeaxanthin,phytoene and phytofluene) are measured using high performance liquid chromatography with multiwavelength photodiode-array absorbance detection. A small volume (150 μL) of serum/plasma is mixed with an equal volume of buffer, and then mixed with 2 volumes of ethanol containing the internal standard (tocol). The analytes are extracted from the aqueous phase into hexane. The combined hexane extracts are dried under vacuum. The extract is redissolved in ethyl acetate and diluted in mobile phase. An aliquot is injected onto a C18 reversed phase column and eluted isocratically. The analytes all possess absorbance and/or fluorescence which are proportional to their concentration in solution; therefore these properties are used for quantitative analysis. The mode of detection is chosen to provide the highest sensitivity and selectivity. Carotenoids are measured by absorbance at 450 nm. Retinol, retinyl esters, phytoene and phytofluene are measured by UV absorbance near their absorption maxima of 325 nm, 280 nm and 340 nm. Tocopherols have absorption maxima between 292 and 300 nm. Chromatograms are recorded using a computer data system. Analytes are quantified by external standard quantitation using standards to calculate response factors based on the peak area of the analyte. The quantities of analytes are corrected for recovery post-run based upon tocol asan internal standard.

Laboratory testing changed from 2001-2002 and 2003-2004. The National Center for Environmental Health, Centers for Disease & Prevention performed the testing in 2001-2002. Craft Technologies performed the testing in 2003-2004. Craft Technologies measured more analytes in 2003-2004 than theNational Center for Environmental Health, Centers for Disease & Prevention measured in 2001-2002. See the codebooks on the NHANES website for the different tests between the two laboratories.

The age group in which these measurements were made changed from 2001-2002 to 2003-2004. Serum concentrations of vitamin A, vitamin E and carotenoids were tested on participants 3 years and older in 2001- 2002 and on participants 6 years and older in 2003-2004.

The variable names and/or label descriptors changed from 2001-2002 to 2003-2004 for vitamin E and lutein/zeaxanthin. Also, additional analytes were tested in 2003-2004. The following pairs of test names or codes are used synonymously; vitamin E and α-tocopherol; and vitamin A and retinol. The variable names for vitamin E/α-tocopherol changed from LBXVIE/LBDVIESI in 2001-2002 to LBXATC/LBDATCSI in 2003-2004.

The variable name and label descriptor for lutein (LBXLUT/LBXLUTSI) in the 2002 and earlier data is equivalent to the variable name “combined lutein/zeaxanthin” (LBXLUZ/LBXLUZSI) in the 2003-2004 data. This is because the lutein peak in the CDC method included both lutein and zeaxanthin.

Serum concentrations of α-cryptoxanthin (LBXACY/LBDACYSI), δ- tocopherol(LBXDTC/LBDDTCSI), cis-lycopene (LBXCLC/LBDCLCSI), total lycopene (LBXLCC/LBDLCCSI), lutein (LBXLUT/LBDLUTSI), phytofluene (LBXPHF/LBDPHFSI), phytoene (LBXPHE/LBDPHESI),
and zeaxanthin (LBXZEA/LBDZEASI) were measured in 2003-2004, but not in 2001-2002.

A detailed description of the laboratory method used can be found on the NHANES website.

Data Processing and Editing

Serum specimens were processed, stored, and shipped to CTI in Wilson, NC for analysis.

Detailed specimen collection and processing instructions are discussed in the NHANES LPM. Vials werestored under appropriate frozen (–20°C) conditions until they were shipped to CTI.

Twenty-one derived variables were created in this data file. The formula for its derivatization is as follows:

The α-tocopherol (Vitamin E) results in ug/dL were converted into umol/L by multiplying by 0.02322.

The α-carotene results in ug/dL were converted into umol/L by multiplying by 0.01863 .

The α-cryptoxanthin results in ug/dL were converted into umol/L by multiplying by 0.01810.

The trans-β-carotene results in ug/dL were converted into umol/L by multiplying by 0.01863.

The total β-carotene results in ug/dL were converted into umol/L by multiplying by 0.01863 .

The cis-β carotene results in ug/dL were converted into umol/L by multiplying by 0.01863 .

The cis-lycopene results in ug/dL were converted into umol/L by multiplying by 0.01863.

The cis-lutein/zeaxanthin results in ug/dL were converted into umol/L by multiplying by 0.01758.

The β-cryptoxanthin results in ug/dL were converted into umol/L by multiplying by 0.01810.

The δ-tocopherol results in ug/dL were converted into umol/L by multiplying by 0.02485

The γ-tocopherol results in ug/dL were converted into umol/L by multiplying by 0.02402

The total lycopene results in ug/dL were converted into umol/L by multiplying by 0.01863

The lutein results in ug/dL were converted into umol/L by multiplying by 0.01758.

The combined lutein/zeaxanthin results in ug/dL were converted into umol/L by multiplying by 0.01758.

The trans-lycopene results in ug/dL were converted into umol/L by multiplying by 0.01863.

The phytofluene results in ug/dL were converted into umol/L by multiplying by 0.01843.

The phytoene results in ug/dL were converted into umol/L by multiplying by 0.01837.

The retinyl palmitate results in ug/dL were converted into umol/L by multiplying by 0.03491.

The retinyl stearate results in ug/dL were converted into umol/L by multiplying by 0.03491.

The vitamin A (retinol) results in ug/dL were converted into umol/L by multiplying by 0.03491.

The zeaxanthin results in ug/dL were converted into umol/L by multiplying by 0.01758.

Detailed instructions on specimen collection and processing can be found on the NHANES website.

Laboratory Quality Assurance and Monitoring

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/Medical Technologists Procedures Manual (LPM). Read the LABDOC file for detailed QA/QC protocols.

A detailed description of the quality assurance and quality control procedures can be found on the NHANES website.

Analytic Notes

The analysis of NHANES 2003–2004 laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES 2003–2004 Household Questionnaire Data Files contain demographic data, health indicators, and other related information collected during household interviews. The Household Questionnaire Data Files also contain all survey design variables and sample weights required to analyze these data. The Phlebotomy Examination file includes auxiliary information on duration of fasting, the time of day of the venipuncture, and the conditions precluding venipuncture. The Household Questionnaire and Phlebotomy Exam files may be linked to the laboratory data file using the unique survey participant identifier SEQN.

Regression Analysis for 2001-2002 and 2003-2004 for Vitamins A, E, and Carotenoids:

In 2001-2002, Vitamins A, E and Carotenoids were analyzed using a HPLC method performed at CDC/NCEH [See Lab 6 in NHANES 2001-2002 for method details]. In 2003-2004, Vitamins A, E and Carotenoids were analyzed using a comparable HPLC method at Craft Technologies, Inc. (CTI). Crossover studies between CDC/NCEH and CTI were done in early 2003 and late 2004 and differences existed between the methods for some analytes. The following Deming regression analyses were performed to compare data from 2001-2002 to 2003-2004:

Early 2003 Deming Regression Analysis for A/E/Carotenoids Y(CDC)=X(CTI) in μg/dL

Test	n	Y(CDC)=X(CTI)	r2
Alpha-Carotene	100	y = 0.9734x + 0.1847	0.9944
Trans-Beta-Carotene	100	y = 1.0764x - 0.0248	0.9971
Cis-Beta-Carotene	100	y = 0.8017x - 0.0372	0.9685
Beta-Cryptoxanthin	100	y = 1.1359x - 0.2116	0.9945
Gamma-Tocopherol	100	y = 1.0346x - 8.5749	0.9818
Lutein/Zeaxanthin	99	y = 0.9321x + 0.1231	0.9455
Trans-Lycopene	100	y = 1.0719x - 0.1817	0.9947
Retinyl Palmitate	100	y = 1.0245x + 0.5039	0.1988
Retinyl Stearate	97	y = 0.803x - 0.0048	0.9807
Vitamin A	100	y = 0.9406x - 0.1199	0.9887
Vitamin E	100	y = 0.9541x - 22.231	0.9941

Late 2004 Deming Regression Analysis for A/E/Carotenoids Y(CDC)=X(CTI) in μg/dL

Test	n	Y(CDC)=X(CTI)	r2
Alpha-Carotene	99	y = 0.9989x + 0.2204	0.9768
Trans-Beta-Carotene	98	y = 1.0275x + 1.2976	0.9960
Cis-Beta-Carotene	99	y = 0.7154x + 0.1344	0.9826
Beta-Cryptoxanthin	98	y = 1.0824x - 0.056	0.9696
Gamma-Tocopherol	98	y = 1.0306x - 5.523	0.9922
Lutein/Zeaxanthin	99	y = 1.1082x - 1.602	0.9141
Trans-Lycopene	98	y = 1.0971x + 0.0645	0.9737
Retinyl Palmitate	98	y = 0.7989x + 1.2106	0.8845
Retinyl Stearate	98	y = 0.7681x + 0.1483	0.9621
Vitamin A	99	y = 0.9806x + 0.2901	0.9934
Vitamin E	98	y = 0.93x + 22.614	0.9905

Combined Deming Regression Analysis for A/E/Carotenoids Y(CDC)=X(CTI) in μg/dL

Test	n	Y(CDC)=X(CTI)	r2
Alpha-Carotene	199	y = 0.9837x + 0.2137	0.9877
Trans-Beta-Carotene	198	y = 1.0339x + 0.8812	0.9960
Cis-Beta-Carotene	199	y = 0.7232x + 0.0879	0.9815
Beta-Cryptoxanthin	198	y = 1.0958x - 0.0542	0.9793
Gamma-Tocopherol	198	y = 1.029x - 6.287	0.9893
Lutein/Zeaxanthin	198	y = 1.0641x - 1.2402	0.9225
Trans-Lycopene	198	y = 1.0852x - 0.0681	0.9849
Retinyl Palmitate	198	y = 0.8227x + 0.99	0.7603
Retinyl Stearate	195	y = 0.7881x + 0.0711	0.9675
Vitamin A	199	y = 0.9805x - 1.0069	0.9871
Vitamin E	198	y = 0.9397x + 1.649	0.9914

The combined regression was performed using crossover data from early 2003 and late 2004. The data user may wish to apply regression formulas to compare results from 2001-2002 and 2003-2004.

Codebook and Frequencies