Table of Contents

Locator Record

Title: Dietary Interview - Individual Foods File (DRXIFF_B )
Contact Number: 1-866-441-NCHS
Years of Content: 2001 - 2002
First Published: September, 2004
Revised: July, 2010
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject:What We Eat in America: Individual Foods File
Record Source: NHANES 2001 - 2002
Survey Methodology: NHANES 2001 - 2002 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

The objective of the dietary interview component is to obtain detailed dietary intake information from the NHANES participants. The dietary intake data are used to estimate the types and amounts of foods and beverages consumed during the 24-hour period prior to the interview (midnight to midnight), and to estimate intakes of energy, nutrients, and other food components from those foods and beverages. Following the dietary recall, respondents are asked questions on water consumption during the previous 24-hour period, salt use, and whether the person’s intake on the previous day was usual or unusual. Children 1 to 5 years old and women 16 to 49 years old are also asked about their frequency of fish and shellfish consumption during the past 30 days.

This release of the dietary intake data represents, for the first time, the integration of two nationwide dietary intake surveys - USDA’s Continuing Survey of Food Intakes by Individuals (CSFII) and DHHS’s National Health and Nutrition Examination Survey (NHANES). This new integrated dietary component is collected as part of NHANES and is called What We Eat in America. Under the integrated framework, DHHS is responsible for the sample design and data collection and USDA is responsible for the survey’s dietary data collection methodology, maintenance of the databases used to code and process the data, and data review and processing.

Survey integration of dietary data collection began in NHANES 2002. Because NHANES is on a two-year data release cycle, this first release of the integrated survey includes dietary data collected in 2001 from NHANES plus data from the integrated survey collected in 2002. Collection and processing procedures for the two years were similar. Differences between the two years, along with steps taken to reconcile these differences, are discussed throughout this document.

Data collection for the What We Eat in America 2002 also included a second day recall that was collected by telephone. Because of confidentiality issues concerning the release of single-year data from NHANES, dietary data for the 2002 Day 2 telephone interview will not be publicly released. Only Day 1 interview data are included in the present release.

Restricted data, such as the 2002 Day 2 dietary data, may be made available at the Research Data Center located at the National Center for Health Statistics (NCHS) headquarters in Hyattsville, MD. A research proposal for using the restricted data must be submitted to NCHS for review and approval. Instructions for requesting use of these data are available at: http://www.cdc.gov/rdc/.

Two data files were produced from the Day 1 dietary interview for this release:

  1. Total Nutrient Intakes File (DRXTOT_B) that consists of daily total nutrient intakes from foods and beverages, total amount of water consumed, and frequency of fish and shellfish consumption for survey participants.
  2. Individual Foods File (DRXIFF_B) that includes detailed information about the type and amount of individual foods reported by each respondent, as well as amounts of nutrients from each food.

Nutrient intakes reported in these files do not include those obtained from dietary supplements, medications or plain drinking water.

This document provides additional details important to understanding the content of the Individual Foods File (DRXIFF_B). This file includes one record per food for each survey participant. Each record contains food-specific data (food code, food amount, time, eating occasion) and amounts of nutrients from each food in units appropriate to the nutrient. Food records are sequentially numbered.

Text descriptions for each food record are provided in a separate data file called Food Code Format File (DRXFMT_B). SAS code to link the Food Code Format File with the Individual Foods File or to obtain a list of formatted text labels of the food codes is provided in the documentation for the DRXFMT_B file. Expanded food descriptions can be found in the food descriptions component of the USDA Food and Nutrient Database for Dietary Studies (FNDDS). The FNDDS is available for free download from the Food Surveys Research Group (FSRG) website (http://www.ars.usda.gov/ba/bhnrc/fsrg).

Eligible Sample

All NHANES examined survey participants are eligible for the dietary interview component. However, several questions that follow the 24-hour recall are only asked of a subset of survey participants. Frequency of fish and shellfish consumption is only reported for children 1-5 years old and women 16-49 years of age, and information on the use of table salt is only reported for participants 1 year and older.

Protocol and Procedure

The examination protocol and data collection methods are fully documented in the NHANES Dietary Interviewers Procedures Manuals (In-person interview: http://www.cdc.gov/nchs/data/nhanes/nhanes_01_02/dietary_year_3.pdf; phone-follow-up interview: http://www.cdc.gov/nchs/data/nhanes/phonefollup_01_02.pdf).

Proxy interviews were conducted for survey participants less than six years of age. Assisted interviews were conducted with survey participants 6 to 11 years of age. Dietary interviews were conducted in English and Spanish. Translators were used to conduct interviews in other languages.

The in-person interview was conducted in a private room in the NHANES mobile examination center (MEC). A set of standard measuring guides was available in the MEC dietary interview room for the respondent to use for reporting amounts of foods.

In 2001, dietary intake data were collected using the NHANES computer-assisted dietary interview system (CADI), which was also used to collect dietary data for the 1999-2000 collection period. The CADI is a multiple pass recall method which provides instructions to interviewers for recording information about foods. Additional information about the CADI system is provided in the NHANES 1999-2000 Dietary Interviewers Procedures Manual (http://www.cdc.gov/nchs/nhanes/nhanes1999-2000/current_nhanes_99_00.htm)

In 2002, What We Eat in America data were collected using USDA’s dietary data collection instrument, the Automated Multiple Pass Method (AMPM) (http://www.ars.usda.gov/ba/bhnrc/fsrg). The AMPM was designed to provide a more efficient and accurate means of collecting intakes for large-scale national surveys. The AMPM is a fully computerized recall method that includes an extensive compilation of standardized food-specific questions and possible response options. It features automated routing of questions based on previous answers. The AMPM is updated yearly to capture the changing food supply and to address research needs from the data user community. Additional information about the AMPM is provided in Raper et al (Raper et al., 2004).

Quality Assurance & Quality Control

All dietary interviewers had to complete an intensive one-week training course followed by supervised interview practices before working independently in the field. Retraining sessions were conducted periodically and annually to reinforce the proper protocols and technique.

Interviewers were monitored throughout the data collection period. Monitoring consisted of the following:

In 2001, interviewers reviewed each interview after completion, performing appropriate edits. Interviewers were not required to review interviews collected in 2002 using the USDA’s AMPM because quality control features are built into the software. Incorrect entries are minimized due to automated routing of questions and built-in edits.

Data Processing and Editing

Two similar systems were used to code the intake data for 2001 and 2002. The University of Texas Food Intake Analysis System (FIAS, version 3.99) was used for coding intakes for 2001. For 2002, interview files were imported into Survey Net, a computer-assisted food coding and data management system developed by USDA (Raper et al., 2004). FIAS is a general-use version of the Survey Net software that is available to researchers through the University of Texas.

The USDA FNDDS, version 1, was used for processing the intakes for 2001-2002. The FNDDS includes comprehensive information that can be used to code individual foods and portion sizes and contains nutrient values for calculating nutrient intakes. The FNDDS is available for use in research projects using the 2001-2002 food intake data and in other food intake studies, as well. Additional information (Raper et al., 2004; Bodner-Montville et al, 2006) about the FNDDS and related tools is available at the FSRG website.

Coders were monitored to ensure quality and completeness. Approximately 10 percent of the coder’s work was double-coded and adjudicated, if necessary.

After intake data were coded, various types of reviews were conducted to ensure the quality of the data, including:

An overview of quality assurance procedures conducted during the data processing stage is available at the FSRG website (Anand et al., 2006).

During data processing, the following edits were made to ensure the logical consistency and analytic usefulness of the data:

  1. Adjusted sodium values for certain foods
    Sodium values for home-prepared foods are based on the sodium values of recipe ingredients in the FNDDS. The amount of salt in recipes was reduced, or eliminated, in some cases based on questions about salt use in the dietary interview.
  2. Derived “eaten at home” variable (DRD040Z)
    The question “Was this meal/snack eaten at home?” was included in the 2002 interview, but not in the 2001 interview. The answer to this question in 2001 was derived from the answer to a question about where each food was consumed. If the answer was anything other than “home” for any food reported in an eating occasion, then the “eaten at home” variable was coded as “no”.
  3. Foods eaten in combination
    Foods eaten in combination with other foods, such as cereal with milk, are flagged with a combination food number (DRXCCMNM). Foods flagged with the same combination food number at a given meal were eaten together. Foods are categorized by a combination type code (DRDCCMTZ).

Analytic Notes

The analytic guidelines provided with the 2001-2002 NHANES data release recommend combining 2-year cycles, such as 1999-2000 and 2001-2002, to increase sample size and analytic options. However, the guidelines also advise that the user should verify that data items were collected and reported in a comparable manner in all combined years. Thus, before combining the 1999-2000 and 2001-2002 dietary data, researchers should carefully consider the following information. Between these two time periods, nutrient values for many foods were revised, based on improvements in sampling and analyzing foods. Also, values for new nutrients and food components became available, and units of expression for some existing nutrients were changed. NHANES 2001-2002 nutrient intakes were calculated using USDA’s FNDDS version 1.0, which contains the most up-to-date food composition values available for this time frame. NHANES 1999-2000 nutrient intakes were calculated using an earlier version of the database, the USDA 1994-1998 Survey Nutrient Database. Thus, analyzing merged intake data for these two data sets should be carefully considered for each nutrient. Analyses conducted based on changes in the nutrient databases show that the impact can be significant depending on the nutrient (Anderson et al., 2001; Ahuja et al., 2006).

The Individual Foods File is comprised of food records. In most cases, there are multiple records in the file per survey participant. This file can be linked with other NHANES files by the respondent sequence number (SEQN).

A status code (DRDDRSTZ) is used in the NHANES 2001-2002 dietary interview component to indicate the quality and completeness of the response to the dietary recall section. The dietary recall section status is coded as one of the following:

  1. Reliable and met the minimum criteria
  2. Not reliable or not met the minimum criteria
    No data on total nutrient intake or individual food consumption is provided for these cases.
  3. Reported consuming breast-milk
    Human milk was reported in some dietary recalls. Few respondents could quantify the human milk intake for their breast-fed infants/children. For those cases, no total nutrient intakes were derived. The foods consumed by nursing infants and children are reported in the Individual Foods File.
  4. Not Done
    The dietary recall section of the interview did not take place due to various reasons (such as came late/left early, refusal, illness, emergency, or equipment failure).

In 2002, a question on the source of each food (where it was obtained, such as store, fast food restaurant, cafeteria) was asked. Because this question was not asked in 2001, the source of each food for 2002 dietary interviews will not be publicly released but may be accessible through the NCHS Research Data Center. Instructions for requesting use of these data at the NCHS Data Research Center are available at http://www.cdc.gov/rdc/.

Sample weights for dietary intake data: The 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. The NHANES oversamples blacks, Mexican Americans, low income whites, adolescents 12-19 years, and persons 60 years and older. 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.

For the 2001-2002 NHANES, there were 13,156 persons selected; of these 10,477 were considered respondents to the MEC examination and data collection. However, only 9,883 of the MEC respondents provided complete dietary intakes.

Most analyses of NHANES data use data collected in the MEC and the variable WTMEC2YR should be used for the sample weights. However, for the dietary data, different sample weights are recommended for analysis. Although attempts are made to schedule MEC exams uniformly throughout the week, proportionally more exams occur on weekend days than on weekdays. Because food intake can vary by day of week, use of the MEC weights would disproportionately represent intakes on weekends.

A set of weights WTDRD1 is provided that should be used when an analysis uses the NHANES 2001-2002 dietary recall data (either alone or when nutrient data are used in conjunction with MEC data). The set of weights WTDRD1 is applicable to the 9,883 respondents with dietary data. The weights WTDRD1 were constructed by taking the MEC sample weights (WTMEC2YR) and further adjusting for (a) the additional non-response and (b) the differential allocation by day of the week for the dietary intake data collection. These weights are more variable than the MEC weights, and the sample size is smaller, so estimated standard errors using dietary data and dietary weights are larger than standard errors for similar estimates based on MEC weights. In addition, a set of four-year dietary weight (WTDR4YR) is also provided that should be used for the combined analyses of NHANES 1999-2000 and NHANES 2001-2002 data.

Note that all sample weights are person-level weights and each set of weights should add to the same population control total as the MEC weights (WTMEC2YR). In addition, the MEC weights (WTMEC2YR) are appropriate for use in the analysis of the fish and shellfish consumption data (i.e., variables DRD340, DRD350A-K, DRD350AQ-JQ, DRD360, DRD370A-V, and DRD370AQ-UQ) and the use of table salt data (i.e., variables DBQ095 and DBD100) located in the Total Nutrient Intake File (DRXTOT_B), if no other dietary data are included in the analysis. Additional explanation of sample weights and appropriate uses are included in the NHANES Analytic Guidelines  (http://www.cdc.gov/nchs/nhanes/survey_methods.htm). Please also refer to the on-line NHANES Tutorial  (http://www.cdc.gov/nchs/tutorials/) for further details on other analytic issues.

References

Codebook and Frequencies

SEQN - Respondent sequence number

Variable Name:
SEQN
SAS Label:
Respondent sequence number
English Text:
Respondent sequence number.
English Instructions:
One of the key variables for the file. Primary key variables: SEQN and DRXILINE
Target:
Both males and females 0 YEARS - 150 YEARS

WTDRD1 - Dietary day one 2-Year sample weight

Variable Name:
WTDRD1
SAS Label:
Dietary day one 2-Year sample weight
English Text:
Dietary day one 2-Year sample weight - Used for 1999-2000 data collection years only
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
617.86932978 to 341097.23732 Range of Values 143004 143004
. Missing 0 143004

WTDR4YR - Dietary day one 4-Year sample weight

Variable Name:
WTDR4YR
SAS Label:
Dietary day one 4-Year sample weight
English Text:
Dietary day one 4-Year sample weight - Used for 1999-2002 data collection years only
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
298.67300602 to 173979.37695 Range of Values 143004 143004
. Missing 0 143004

DRXILINE - Food/individual component number

Variable Name:
DRXILINE
SAS Label:
Food/individual component number
English Text:
Food/individual component number
English Instructions:
One of the key variables for the file. Primary key variables: SEQN and DRXILINE
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 to 46 Range of Values 143004 143004
. Missing 0 143004

DRDDRSTZ - Dietary recall status

Variable Name:
DRDDRSTZ
SAS Label:
Dietary recall status
English Text:
Dietary recall status
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Reliable and met the minimum criteria 140817 140817
2 Not reliable or not met the minimum criteria 0 140817
4 Reported consuming breast-milk 2187 143004
5 Not done 0 143004
. Missing 0 143004

DRDDAY - Intake day of week

Variable Name:
DRDDAY
SAS Label:
Intake day of week
English Text:
Intake day of the week
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Sunday 24166 24166
2 Monday 11635 35801
3 Tuesday 9686 45487
4 Wednesday 14947 60434
5 Thursday 14682 75116
6 Friday 36467 111583
7 Saturday 31421 143004
. Missing 0 143004

DRALANG - Language SP/Proxy used mostly

Variable Name:
DRALANG
SAS Label:
Language SP/Proxy used mostly
English Text:
The SP/Proxy spoke mostly:
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 English 125958 125958
2 Spanish 14391 140349
3 English and Spanish 1304 141653
4 Other 164 141817
. Missing 1187 143004

DRXCCMNM - Combination food number

Variable Name:
DRXCCMNM
SAS Label:
Combination food number
English Text:
Combination food number
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 11 Range of Values 143004 143004
. Missing 0 143004

DRDCCMTZ - Combination food type

Variable Name:
DRDCCMTZ
SAS Label:
Combination food type
English Text:
Combination food type
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 Non-combination food 71938 71938
1 Beverage w/ adds 9964 81902
2 Cereal w/ adds 7873 89775
3 Bread/baked products w/ adds 7871 97646
4 Salad 5889 103535
5 Sandwiches 17733 121268
6 Soup 933 122201
7 Frozen meals 148 122349
8 Ice cream/frozen yogurt w/ additions 635 122984
9 Dried beans and vegetable w/ adds 5725 128709
10 Fruit w/ adds 699 129408
11 Tortilla Products 4194 133602
12 Meat, poultry, fish 3683 137285
13 Lunchables 153 137438
90 Other mixtures 5566 143004
. Missing 0 143004

DRD020 - Time of eating occasion (HH:MM)

Variable Name:
DRD020
SAS Label:
Time of eating occasion (HH:MM)
English Text:
What time did you begin to eat/drink the meal/food?
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 86340 Range of Values 143004 143004
. Missing 0 143004

DRD030Z - Name of eating occasion

Variable Name:
DRD030Z
SAS Label:
Name of eating occasion
English Text:
Name of eating occasion
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Breakfast 25398 25398
2 Lunch 30708 56106
3 Dinner/supper 38283 94389
5 Brunch 1669 96058
6 Snack/beverage 30873 126931
8 Infant feeding 3268 130199
9 Extended consumption 2299 132498
10 Desayano (Spanish) 1639 134137
11 Almuerzo (Spanish) 1369 135506
12 Comida (Spanish) 2834 138340
13 Merienda (Spanish) 644 138984
14 Cena (Spanish) 2233 141217
15 Entre comida/bebida/tentempie (Spanish) 962 142179
16 Botana (Spanish) 329 142508
17 Bocadillo (Spanish) 402 142910
91 Other 92 143002
99 Don't know 2 143004
. Missing 0 143004

DRD040Z - Was this food eaten at home?

Variable Name:
DRD040Z
SAS Label:
Was this food eaten at home?
English Text:
Was this food eaten at home?
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 95394 95394
2 No 45684 141078
. Missing 1926 143004

DRDIFDCD - USDA food code

Variable Name:
DRDIFDCD
SAS Label:
USDA food code
English Text:
USDA food code
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
11000000 to 94000000 Range of Values 143004 143004
. Missing 0 143004

DRXIGRMS - Grams

Variable Name:
DRXIGRMS
SAS Label:
Grams
English Text:
Gram weight of the food/individual component
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.02 to 9360 Range of Values 141931 141931
. Missing 1073 143004

DRXIKCAL - Energy (kcal)

Variable Name:
DRXIKCAL
SAS Label:
Energy (kcal)
English Text:
Energy (kcal)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 5384 Range of Values 141931 141931
. Missing 1073 143004

DRXIPROT - Protein (gm)

Variable Name:
DRXIPROT
SAS Label:
Protein (gm)
English Text:
Protein (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 637.52 Range of Values 141931 141931
. Missing 1073 143004

DRXICARB - Carbohydrate (gm)

Variable Name:
DRXICARB
SAS Label:
Carbohydrate (gm)
English Text:
Carbohydrate (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 754.14 Range of Values 141931 141931
. Missing 1073 143004

DRXISUGR - Total sugars (gm)

Variable Name:
DRXISUGR
SAS Label:
Total sugars (gm)
English Text:
Total sugars (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 631.75 Range of Values 141931 141931
. Missing 1073 143004

DRXIFIBE - Dietary fiber (gm)

Variable Name:
DRXIFIBE
SAS Label:
Dietary fiber (gm)
English Text:
Dietary fiber (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 71.9 Range of Values 141931 141931
. Missing 1073 143004

DRXITFAT - Total fat (gm)

Variable Name:
DRXITFAT
SAS Label:
Total fat (gm)
English Text:
Total fat (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 347.73 Range of Values 141931 141931
. Missing 1073 143004

DRXISFAT - Total saturated fatty acids (gm)

Variable Name:
DRXISFAT
SAS Label:
Total saturated fatty acids (gm)
English Text:
Total saturated fatty acids (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 100.302 Range of Values 141931 141931
. Missing 1073 143004

DRXIMFAT - Total monounsaturated fatty acids (gm)

Variable Name:
DRXIMFAT
SAS Label:
Total monounsaturated fatty acids (gm)
English Text:
Total monounsaturated fatty acids (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 176.907 Range of Values 141931 141931
. Missing 1073 143004

DRXIPFAT - Total polyunsaturated fatty acids (gm)

Variable Name:
DRXIPFAT
SAS Label:
Total polyunsaturated fatty acids (gm)
English Text:
Total polyunsaturated fatty acids (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 91.63 Range of Values 141931 141931
. Missing 1073 143004

DRXICHOL - Cholesterol (mg)

Variable Name:
DRXICHOL
SAS Label:
Cholesterol (mg)
English Text:
Cholesterol (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 1859 Range of Values 141931 141931
. Missing 1073 143004

DRXIATOC - Vitamin E as alpha-tocopherol (mg)

Variable Name:
DRXIATOC
SAS Label:
Vitamin E as alpha-tocopherol (mg)
English Text:
Vitamin E as alpha-tocopherol (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 89.44 Range of Values 141931 141931
. Missing 1073 143004

DRXIRET - Retinol (mcg)

Variable Name:
DRXIRET
SAS Label:
Retinol (mcg)
English Text:
Retinol (mcg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 30961 Range of Values 141931 141931
. Missing 1073 143004

DRXIVARA - Vitamin A, RAE (mcg)

Variable Name:
DRXIVARA
SAS Label:
Vitamin A, RAE (mcg)
English Text:
Vitamin A as retinol activity equivalents (mcg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 31025 Range of Values 141931 141931
. Missing 1073 143004

DRXIACAR - Alpha-carotene (mcg)

Variable Name:
DRXIACAR
SAS Label:
Alpha-carotene (mcg)
English Text:
Alpha-carotene (mcg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 30741 Range of Values 141931 141931
. Missing 1073 143004

DRXIBCAR - Beta-carotene (mcg)

Variable Name:
DRXIBCAR
SAS Label:
Beta-carotene (mcg)
English Text:
Beta-carotene (mcg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 65865 Range of Values 141931 141931
. Missing 1073 143004

DRXICRYP - Beta-cryptoxanthin (mcg)

Variable Name:
DRXICRYP
SAS Label:
Beta-cryptoxanthin (mcg)
English Text:
Beta-cryptoxanthin (mcg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 3534 Range of Values 141931 141931
. Missing 1073 143004

DRXILYCO - Lycopene (mcg)

Variable Name:
DRXILYCO
SAS Label:
Lycopene (mcg)
English Text:
Lycopene (mcg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 142478 Range of Values 141931 141931
. Missing 1073 143004

DRXILZ - Lutein + zeaxanthin (mcg)

Variable Name:
DRXILZ
SAS Label:
Lutein + zeaxanthin (mcg)
English Text:
Lutein + zeaxanthin (mcg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 67174 Range of Values 141931 141931
. Missing 1073 143004

DRXIVB1 - Thiamin (Vitamin B1) (mg)

Variable Name:
DRXIVB1
SAS Label:
Thiamin (Vitamin B1) (mg)
English Text:
Thiamin (Vitamin B1) (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 10.269 Range of Values 141931 141931
. Missing 1073 143004

DRXIVB2 - Riboflavin (Vitamin B2) (mg)

Variable Name:
DRXIVB2
SAS Label:
Riboflavin (Vitamin B2) (mg)
English Text:
Riboflavin (Vitamin B2) (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 14.329 Range of Values 141931 141931
. Missing 1073 143004

DRXINIAC - Niacin (mg)

Variable Name:
DRXINIAC
SAS Label:
Niacin (mg)
English Text:
Niacin (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 132.5 Range of Values 141931 141931
. Missing 1073 143004

DRXIVB6 - Vitamin B6 (mg)

Variable Name:
DRXIVB6
SAS Label:
Vitamin B6 (mg)
English Text:
Vitamin B6 (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 21.732 Range of Values 141931 141931
. Missing 1073 143004

DRXIFOLA - Total Folate (mcg)

Variable Name:
DRXIFOLA
SAS Label:
Total Folate (mcg)
English Text:
Total Folate (mcg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 2667 Range of Values 141931 141931
. Missing 1073 143004

DRXIFA - Folic acid (mcg)

Variable Name:
DRXIFA
SAS Label:
Folic acid (mcg)
English Text:
Folic acid (mcg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 2604 Range of Values 141931 141931
. Missing 1073 143004

DRXIFF - Food folate (mcg)

Variable Name:
DRXIFF
SAS Label:
Food folate (mcg)
English Text:
Food folate (mcg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 1324 Range of Values 141931 141931
. Missing 1073 143004

DRXIFDFE - Folate, DFE (mcg)

Variable Name:
DRXIFDFE
SAS Label:
Folate, DFE (mcg)
English Text:
Folate as dietary folate equivalents (mcg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 4488 Range of Values 141931 141931
. Missing 1073 143004

DRXIVB12 - Vitamin B12 (mcg)

Variable Name:
DRXIVB12
SAS Label:
Vitamin B12 (mcg)
English Text:
Vitamin B12 (mcg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 333.05 Range of Values 141931 141931
. Missing 1073 143004

DRXIVC - Vitamin C (mg)

Variable Name:
DRXIVC
SAS Label:
Vitamin C (mg)
English Text:
Vitamin C (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 1156.1 Range of Values 141931 141931
. Missing 1073 143004

DRXIVK - Vitamin K (mcg)

Variable Name:
DRXIVK
SAS Label:
Vitamin K (mcg)
English Text:
Vitamin K (mcg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 2933.3 Range of Values 141931 141931
. Missing 1073 143004

DRXICALC - Calcium (mg)

Variable Name:
DRXICALC
SAS Label:
Calcium (mg)
English Text:
Calcium (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 9314 Range of Values 141931 141931
. Missing 1073 143004

DRXIPHOS - Phosphorus (mg)

Variable Name:
DRXIPHOS
SAS Label:
Phosphorus (mg)
English Text:
Phosphorus (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 7483 Range of Values 141931 141931
. Missing 1073 143004

DRXIMAGN - Magnesium (mg)

Variable Name:
DRXIMAGN
SAS Label:
Magnesium (mg)
English Text:
Magnesium (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 1028 Range of Values 141931 141931
. Missing 1073 143004

DRXIIRON - Iron (mg)

Variable Name:
DRXIIRON
SAS Label:
Iron (mg)
English Text:
Iron (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 121.04 Range of Values 141931 141931
. Missing 1073 143004

DRXIZINC - Zinc (mg)

Variable Name:
DRXIZINC
SAS Label:
Zinc (mg)
English Text:
Zinc (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 281.4 Range of Values 141931 141931
. Missing 1073 143004

DRXICOPP - Copper (mg)

Variable Name:
DRXICOPP
SAS Label:
Copper (mg)
English Text:
Copper (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 58.455 Range of Values 141931 141931
. Missing 1073 143004

DRDISODI - Sodium (mg)

Variable Name:
DRDISODI
SAS Label:
Sodium (mg)
English Text:
Sodium (mg)(adjusted for salt use in food preparation)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 16746 Range of Values 141931 141931
. Missing 1073 143004

DRXIPOTA - Potassium (mg)

Variable Name:
DRXIPOTA
SAS Label:
Potassium (mg)
English Text:
Potassium (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 11941 Range of Values 141931 141931
. Missing 1073 143004

DRXISELE - Selenium (mcg)

Variable Name:
DRXISELE
SAS Label:
Selenium (mcg)
English Text:
Selenium (mcg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 838.7 Range of Values 141931 141931
. Missing 1073 143004

DRXICAFF - Caffeine (mg)

Variable Name:
DRXICAFF
SAS Label:
Caffeine (mg)
English Text:
Caffeine (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 3197 Range of Values 141931 141931
. Missing 1073 143004

DRXITHEO - Theobromine (mg)

Variable Name:
DRXITHEO
SAS Label:
Theobromine (mg)
English Text:
Theobromine (mg)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 1423 Range of Values 141931 141931
. Missing 1073 143004

DRXIALCO - Alcohol (gm)

Variable Name:
DRXIALCO
SAS Label:
Alcohol (gm)
English Text:
Alcohol (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 538.5 Range of Values 141931 141931
. Missing 1073 143004

DRXIMOIS - Moisture (gm)

Variable Name:
DRXIMOIS
SAS Label:
Moisture (gm)
English Text:
Moisture (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 8910.72 Range of Values 141931 141931
. Missing 1073 143004

DRXIS040 - SFA 4:0 (Butanoic) (gm)

Variable Name:
DRXIS040
SAS Label:
SFA 4:0 (Butanoic) (gm)
English Text:
SFA 4:0 (Butanoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 6.368 Range of Values 141931 141931
. Missing 1073 143004

DRXIS060 - SFA 6:0 (Hexanoic) (gm)

Variable Name:
DRXIS060
SAS Label:
SFA 6:0 (Hexanoic) (gm)
English Text:
SFA 6:0 (Hexanoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 3.184 Range of Values 141931 141931
. Missing 1073 143004

DRXIS080 - SFA 8:0 (Octanoic) (gm)

Variable Name:
DRXIS080
SAS Label:
SFA 8:0 (Octanoic) (gm)
English Text:
SFA 8:0 (Octanoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 3.72 Range of Values 141931 141931
. Missing 1073 143004

DRXIS100 - SFA 10:0 (Decanoic) (gm)

Variable Name:
DRXIS100
SAS Label:
SFA 10:0 (Decanoic) (gm)
English Text:
SFA 10:0 (Decanoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 3.98 Range of Values 141931 141931
. Missing 1073 143004

DRXIS120 - SFA 12:0 (Dodecanoic) (gm)

Variable Name:
DRXIS120
SAS Label:
SFA 12:0 (Dodecanoic) (gm)
English Text:
SFA 12:0 (Dodecanoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 17.404 Range of Values 141931 141931
. Missing 1073 143004

DRXIS140 - SFA 14:0 (Tetradecanoic) (gm)

Variable Name:
DRXIS140
SAS Label:
SFA 14:0 (Tetradecanoic) (gm)
English Text:
SFA 14:0 (Tetradecanoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 14.63 Range of Values 141931 141931
. Missing 1073 143004

DRXIS160 - SFA 16:0 (Hexadecanoic) (gm)

Variable Name:
DRXIS160
SAS Label:
SFA 16:0 (Hexadecanoic) (gm)
English Text:
SFA 16:0 (Hexadecanoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 46.788 Range of Values 141931 141931
. Missing 1073 143004

DRXIS180 - SFA 18:0 (Octadecanoic) (gm)

Variable Name:
DRXIS180
SAS Label:
SFA 18:0 (Octadecanoic) (gm)
English Text:
SFA 18:0 (Octadecanoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 23.635 Range of Values 141931 141931
. Missing 1073 143004

DRXIM161 - MFA 16:1 (Hexadecenoic) (gm)

Variable Name:
DRXIM161
SAS Label:
MFA 16:1 (Hexadecenoic) (gm)
English Text:
MFA 16:1 (Hexadecenoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 7.334 Range of Values 141931 141931
. Missing 1073 143004

DRXIM181 - MFA 18:1 (Octadecenoic) (gm)

Variable Name:
DRXIM181
SAS Label:
MFA 18:1 (Octadecenoic) (gm)
English Text:
MFA 18:1 (Octadecenoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 168.5 Range of Values 141931 141931
. Missing 1073 143004

DRXIM201 - MFA 20:1 (Eicosenoic) (gm)

Variable Name:
DRXIM201
SAS Label:
MFA 20:1 (Eicosenoic) (gm)
English Text:
MFA 20:1 (Eicosenoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 17.849 Range of Values 141931 141931
. Missing 1073 143004

DRXIM221 - MFA 22:1 (Docosenoic) (gm)

Variable Name:
DRXIM221
SAS Label:
MFA 22:1 (Docosenoic) (gm)
English Text:
MFA 22:1 (Docosenoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 25.281 Range of Values 141931 141931
. Missing 1073 143004

DRXIP182 - PFA 18:2 (Octadecadienoic) (gm)

Variable Name:
DRXIP182
SAS Label:
PFA 18:2 (Octadecadienoic) (gm)
English Text:
PFA 18:2 (Octadecadienoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 91.63 Range of Values 141931 141931
. Missing 1073 143004

DRXIP183 - PFA 18:3 (Octadecatrienoic) (gm)

Variable Name:
DRXIP183
SAS Label:
PFA 18:3 (Octadecatrienoic) (gm)
English Text:
PFA 18:3 (Octadecatrienoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 8.639 Range of Values 141931 141931
. Missing 1073 143004

DRXIP184 - PFA 18:4 (Octadecatetraenoic) (gm)

Variable Name:
DRXIP184
SAS Label:
PFA 18:4 (Octadecatetraenoic) (gm)
English Text:
PFA 18:4 (Octadecatetraenoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 0.485 Range of Values 141931 141931
. Missing 1073 143004

DRXIP204 - PFA 20:4 (Eicosatetraenoic) (gm)

Variable Name:
DRXIP204
SAS Label:
PFA 20:4 (Eicosatetraenoic) (gm)
English Text:
PFA 20:4 (Eicosatetraenoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 1.538 Range of Values 141931 141931
. Missing 1073 143004

DRXIP205 - PFA 20:5 (Eicsapentaenoic) (gm)

Variable Name:
DRXIP205
SAS Label:
PFA 20:5 (Eicsapentaenoic) (gm)
English Text:
PFA 20:5 (Eicsapentaenoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 4.108 Range of Values 141931 141931
. Missing 1073 143004

DRXIP225 - PFA 22:5 (Docosapentaenoic) (gm)

Variable Name:
DRXIP225
SAS Label:
PFA 22:5 (Docosapentaenoic) (gm)
English Text:
PFA 22:5 (Docosapentaenoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 1.456 Range of Values 141931 141931
. Missing 1073 143004

DRXIP226 - PFA 22:6 (Docosahexaenoic) (gm)

Variable Name:
DRXIP226
SAS Label:
PFA 22:6 (Docosahexaenoic) (gm)
English Text:
PFA 22:6 (Docosahexaenoic) (gm)
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 4.287 Range of Values 141931 141931
. Missing 1073 143004

Appendix 1: Dietary Interview - Food Code Format File (DRXFMT_B)

This dataset is a technical support file for the Individual Foods File (DRXIFF_B) of the dietary interview component. It provides text descriptions for the food codes used in the Individual Foods File. The source of the text descriptions used in this file is the USDA Food and Nutrient Database for Dietary Studies (FNDDS), version 1. Please refer to the documentation for the Individual Foods File for details information on the dietary interview component and related dietary data files.

The Food Code Format File was created for linking the text descriptions with the food codes used in the Individual Foods File. There are three variables included in the file:

1) FMTNAME: a text field encoding the name of the key variable (i.e., DRDIFDCD) used to link with the Individual Foods File;
2) START: the numeric value of the USDA food codes;
3) VALUE: the text description for the correspondent food code.
The following is an example SAS code to associate the text descriptions with the food codes using the proc format option:

Assuming that the individual foods file (DRXIFF_B) and the Format file (DRXFMT_B) have been copied to a SAS library NHANES:

Options FmtSearch = (NHANES);
Proc Format CntlIn=NHANES.DRXFMT_B Library=NHANES;
Proc DataSets Lib=NHANES;
Modify DRXIFF_B;
FORMAT DRDIFDCD DRDIFDCD.; Quit;

Alternatively, data users may use the format statement in proc or data steps to apply the format when needed. For example:

Proc Format CntlIn=NHANES.DRXFMT_B
Proc Freq Data=NHANES.DRXIFF_B; Tables DRDIFDCD; Format DRDIFDCD DRDIFDCD.;
Run;

To simply obtain a listing of formatted text labels for each food code, data users can apply the following SAS code:

Options LS=240; Proc Print Data= NHANES.DRXFMT_B; Run;
Note that the text label is up to 60 characters long.

Expanded food descriptions can be found in the food descriptions component1 of the USDA Food and Nutrient Database for Dietary Studies (FNDDS). The FNDDS2 is available from the Food Surveys Research Group (FSRG) website.

Reference:
1. Food Surveys Research Group. FNDDS Format and Files. Jul 7, 2004. Available at: http://www.barc.usda.gov/bhnrc/foodsurvey/fndds_components.html#nutrients
2. Food Surveys Research Group. Introducing... USDA Food and Nutrient Database for Dietary Studies, 1.0. Jun 21, 2004. Available at: http://www.barc.usda.gov/bhnrc/foodsurvey/fndds_intro.html