Table of Contents

Locator Record

Title: Dietary Interview (Individual Foods File) (DRXIFF )
Contact Number: 1-866-441-NCHS
Years of Content: 1999 - 2000
First Published: June, 2002
Revised: July, 2010
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject:Dietary interview component provides detailed dietary intake information from NHANES participants.
Record Source: NHANES 1999 - 2000
Survey Methodology: NHANES 1999 - 2000 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 examined sample. All examinees are eligible for this component. The dietary intake data are used to estimate total intake of energy, nutrients, and non-nutrient food components from foods and beverages that were consumed during the 24-hour period prior to the interview (midnight to midnight). Following the dietary recall, a short "post-recall" questionnaire is administered; respondents estimate their intake of plain water during the previous 24-hour time period, and frequency of fish and shellfish consumption during the past 30 days. Two data files were produced from the dietary interview dataset: the Total Nutrient Intakes File (DRXTOT) that consists of total nutrient intakes, intake of plain water, and frequency of fish and shellfish data; and the Individual Foods File (DRXIFF) that includes detailed information about the individual foods reported by respondents. Nutrient intakes reported in these files do not include those obtained from dietary supplements, medications or plain drinking water.

Protocol and Procedure

Data Collection Methods

The NHANES computer-assisted dietary interview (CADI) system is an automated data collection form that was developed using Power Builder™; several databases (i.e., Quick List food list, brand name food list, and food amount unit list) are linked to this system. Food probes that were used in previous NHANES and USDA surveys became part of the built-in features of the system, developed using RoboHelp™. The CADI provides a standardized interview format to collect NHANES dietary interview data.

The interviewers follow the scripts provided in the system screens to explain the dietary interview component to the respondents. The CADI screens include data entry screens, food probe information screens, and a post-recall questionnaire. The interviewers also record administrative information about the interview such as the main respondent and language of the interview, and reliability and completeness of the data.

The CADI interface includes the following screen features and data collection components:

A “multiple pass” 24-hour dietary interview format was used to collect detailed information about all foods and beverages. The interview passes included the following:

  1. Quick List: Respondent was asked to recall all foods and beverages consumed in a 24-hour period the day before the interview without interrupting.
  2. Time, Occasion and Place: Respondent was asked to report the time and place each food was eaten and what they would call the eating occasion for the food. Afterwards, a list of frequently forgotten foods was shown to probe the respondent for any forgotten foods or drinks.
  3. Food Details: Specific food probes were used to collect detailed information for each food reported. This includes a complete description of each food and the amount eaten.
  4. Final Review: The reported foods were reviewed with the respondent in chronological order. Any additional foods remembered during the process were added to the record as well as modifications for reported foods.

The Post-Dietary Recall Questionnaire was administered after the 24-hour recall.
Detailed descriptions of the dietary interview methods are provided in the NHANES Dietary Interviewer’s Training Manual, available at: http://www.cdc.gov/nchs/nhanes/nhanes1999-2000/current_nhanes_99_00.htm.

Examination Protocol

All examinees are eligible for the dietary interview component. Proxy respondents were permitted for survey participants less than six years of age. Assisted interviews were completed with survey participants 6-11 years of age.

The primary interview mode for the NHANES 1999-2000 dietary recall component is the in-person interview mode. Interviews were conducted in a private setting in the NHANES Mobile Examination Centers (MECs). A methodological study, the Dietary Interview Mode Evaluation Study (DIMES) was conducted on a subsample of primary sampling units (PSUs) in both 1999 and 2000. The purpose of the DIMES was to test the operational feasibility of the telephone interview mode within the NHANES setting. For dietary interviews conducted in the DIMES PSUs, half were completed in-person and half were completed by telephone.

According to the NHANES sampling procedure, each participant was randomly assigned to either a morning exam session or an afternoon/evening exam session for his/her MEC visit. During the DIMES, examinees randomly assigned to the morning session completed the dietary interviewin- person in the MEC. Those persons randomly assigned to an afternoon or evening MEC examination session were asked to schedule an appointment for a telephone dietary interview; a small percentage of afternoon and evening sample examinees completed their interviews in-person due to lack of telephone or personal scheduling problems. Telephone dietary interviews were conducted 4-10 days after the MEC health examination.

Dietary interviews were conducted in English and Spanish. Translators were used to conduct interviews in other languages.

Survey Staff

Trained, bilingual dietary interviewers collected all dietary interview data. Dietary interviewers were required to have a B.S. Degree in Food and Nutrition or Home Economics (with at least 10 credit hours in food and nutrition). All interviewers completed an intensive 2-week training course; formal training was followed by a week of supervised, practice interviewing.

Data Collection Forms

Please refer to the Dietary Interviewer’s Training Manual, available at: http://www.cdc.gov/nchs/nhanes/nhanes1999-2000/current_nhanes_99_00.htm. The Manual includes pictures of the CADI system screens, measurement guides, and charts used to collect dietary information. All data were collected and transmitted via automated systems; no printed forms were used.

Quality Assurance & Quality Control

The interviewers were required to review and edit all of their interviews. Written guidelines for completing the required procedures were developed for all survey staff. These procedures were reinforced during reviews of taped interviews and in-person observations, staff retraining, memos to the field, and informal e-mail correspondence.

The initial quality control consisted of:

Data Processing and Editing

Interview data files were sent back to the home office electronically. The interview files were imported into the University of Texas Food Intake Analysis System (FIAS) for coding. FIAS version 3.99 with the USDA 1994-98 Survey Nutrient Database was used to code and report the NHANES 1999-2000 data.

After the initial coding, data files were transmitted for final processing. The final data processing consisting of:

This file, titled “Individual Foods File”, provides detailed information including eating occasions (meal names), places where foods were eaten and time of eating of all individual foods and beverages reported by respondents during the dietary interview. All foods have been assigned an USDA food code. Foods with modified recipes including those that are not in the USDA database are flagged by variable DRDMRUF. Gram weight consumed and nutrient values are reported for each food.

The text descriptions of each food record are provided in a separate data file called “Food Code Format File (DRXFMT)”. Please refer to the documentation for DRXFMT for details. 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.
Food records reported by the respondent are sequentially numbered. Foods that were eaten in combination with other foods, such as cereal with milk, are flagged by the variable DRDCFF with value equal to “1”. All the combination foods reported by a respondent are numbered with a “combination food number (DRXCCMNM)”. The same combination food number identifies foods eaten together. The types of combination foods are categorized by a combination type code (DRDCCMTY) with 24 categories.

Information about total nutrient intakes, intake of plain water during the previous 24-hours, and frequency of fish and shellfish consumption during the past 30 days of the respondent is contained in a separate NHANES 1999-2000 Dietary Data File titled “Total Nutrient Intakes File”.

Analytic Notes

As was mentioned previously, two interview modes (in-person and telephone) were used to collect NHANES 1999-2000 dietary interview data. The variable DRDINTMD indicates the actual mode by which the interview was administered. Analysis of dietary data should include investigation of the potential effect of interview mode on the estimates of interest. Data users who are interested in linking dietary data with data from other exam components such as blood biochemical data should be cognizant of the time lapse between the collections of phone-administered dietary interview (DRDINTMD=2) and other data of interest. Telephone dietary interviews were conducted 4-10 days after the NHANES health examination.

Special Notes on Using the Dataset

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

A status code (DRDDRSTS) is used in the current NHANES dietary interview component to indicate the quality and completeness of response to the dietary recall section. The dietary recall section status is coded as follows:

  1. Reliable and met the minimum criteria
    The recall record was verified as reliable and met the following minimum criteria for the overall quality and completeness of the reported dietary information:
    1. Less than 25% foods with missing descriptive information (e.g., caffeinated or decaffeinated, preparation methods, or brand names);
    2. Less than 15% foods with missing amounts; and
    3. Any meal reported must have at least one known food. For example, if a respondent reported having a lunch but could not remember any foods from that lunch, the recall did not meet the criterion.
    4. Reliable but did not meet the minimum criteria
      The dietary recall record was verified as reliable but did not meet the minimum criteria as stated in code 1.
    5. Not reliable
      The dietary recall information provided by the respondent was determined to be unreliable. No data on individual food consumption or total nutrient intake was provided in the dataset for unreliable cases.
    6. Breast-fed infant or child
      The foods reported during the dietary recall interview included human milk. Few respondents could quantify the human milk intake for their breast-fed
      infants/children. The foods consumed by nursing infants and children are reported in the Individual Foods File. For those who could not quantify the amount of human milk intake, gram weight consumed and nutrient values of the human milk records were set to missing.
    7. Not Done
      The dietary recall section of the interview did not take place due to various reasons (e.g. came late/left early, refusal, illness, emergency, or equipment failure).

    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 1999-2000 NHANES, there were 12,160 persons selected; of these 9,282 were considered respondents to the MEC examination and data collection. However, only 8,730 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 1999-2000 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 8,730 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 DRQ340, DRD350A-K, DRQ350AQ-JQ, DRQ360, DRD370A-V, and DRQ370AQ-UQ) located in the Total Nutrient Intake File (DRXTOT), 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.
    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
    576.43623642 to 537656.81002 Range of Values 126736 126736
    . Missing 1104 127840

    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
    369.94559902 to 200052.31063 Range of Values 126736 126736
    . Missing 1104 127840

    DRXILINE - Food/individ.component number(sequentl#)

    Variable Name:
    DRXILINE
    SAS Label:
    Food/individ.component number(sequentl#)
    English Text:
    Food/Individual Component Number (sequential 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 49 Range of Values 127840 127840
    . Missing 0 127840

    DRDDRSTS - Dietary recall status

    Variable Name:
    DRDDRSTS
    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 meet minimum criteria 125226 125226
    2 Reliable but not meet minimum criteria 1104 126330
    3 Not reliable 0 126330
    4 Breast-fed infant or child 1510 127840
    5 Not done 0 127840
    . Missing 0 127840

    DRDINTMD - Mode of interview

    Variable Name:
    DRDINTMD
    SAS Label:
    Mode of interview
    English Text:
    Mode of interview
    Target:
    Both males and females 0 YEARS - 150 YEARS
    Code or Value Value Description Count Cumulative Skip to Item
    1 In-person 103424 103424
    2 Telephone 24399 127823
    . Missing 17 127840

    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 17426 17426
    2 Monday 11847 29273
    3 Tuesday 10601 39874
    4 Wednesday 15917 55791
    5 Thursday 16561 72352
    6 Friday 31849 104201
    7 Saturday 23639 127840
    . Missing 0 127840

    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 105922 105922
    2 Spanish 20348 126270
    3 English and Spanish 1295 127565
    4 Other 206 127771
    . Missing 69 127840

    DRXCCMNM - Combination food number(sequential#)

    Variable Name:
    DRXCCMNM
    SAS Label:
    Combination food number(sequential#)
    English Text:
    Combination food number (sequential Number)
    Target:
    Both males and females 0 YEARS - 150 YEARS
    Code or Value Value Description Count Cumulative Skip to Item
    1 to 13 Range of Values 70871 70871
    . Missing 56969 127840

    DRDCCMTY - Combination food type

    Variable Name:
    DRDCCMTY
    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 56969 56969
    1 Baby food combo 1284 58253
    2 Dried beans w/adds 462 58715
    3 Beverage combo 8901 67616
    4 Bread/baked products w/adds 5606 73222
    5 Cereal mix/cereal w/adds 6253 79475
    6 Chips w/adds 827 80302
    7 Crackers w/adds 531 80833
    8 Desserts w/adds 1247 82080
    9 Eggs w/adds 685 82765
    10 Fish w/adds 629 83394
    11 Frozen meal 324 83718
    12 Fruit combo 835 84553
    13 Grains w/adds 1022 85575
    14 Meat w/adds 1445 87020
    15 Mixed dish 5833 92853
    17 Poultry w/adds 1739 94592
    18 Salads (greens based) 5042 99634
    19 Salads (non-greens based) 515 100149
    20 Sandwiches 16373 116522
    21 Soup combo 1229 117751
    22 Tortilla w/adds 4808 122559
    23 Vegetable combo 4614 127173
    90 Other foods eaten together 667 127840
    . Missing 0 127840

    DRD020 - Meal time of eating (HH:MM)

    Variable Name:
    DRD020
    SAS Label:
    Meal time of eating (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 127840 127840
    . Missing 0 127840

    DRD030 - Coded meal name

    Variable Name:
    DRD030
    SAS Label:
    Coded meal name
    English Text:
    Coded meal name
    Target:
    Both males and females 0 YEARS - 150 YEARS
    Code or Value Value Description Count Cumulative Skip to Item
    1 Breakfast 21390 21390
    2 Brunch 1335 22725
    3 Lunch 26739 49464
    4 Snack/beverage 26641 76105
    5 Dinner/supper 32031 108136
    6 Infant feeding 4067 112203
    7 Extended consumption 1599 113802
    8 Other 55 113857
    9 Desayuno (Spanish) 2184 116041
    10 Almuerzo (Spanish) 2255 118296
    11 Comida (Spanish) 3964 122260
    12 Merienda (Spanish) 839 123099
    13 Cena (Spanish) 3643 126742
    14 Entre comida/bebida (Spanish) 718 127460
    15 Bocadillo (Spanish) 106 127566
    16 Botana (Spanish) 270 127836
    99 Don't know 4 127840
    . Missing 0 127840

    DRD040 - Meal Place

    Variable Name:
    DRD040
    SAS Label:
    Meal Place
    English Text:
    List of places: Where did you eat this meal/food?
    Target:
    Both males and females 0 YEARS - 150 YEARS
    Code or Value Value Description Count Cumulative Skip to Item
    1 Boat 17 17
    2 Self serve buffet 432 449
    3 Cafeteria 457 906
    4 Car 1961 2867
    5 Community feeding program 114 2981
    6 Deli 104 3085
    7 Fast food 3337 6422
    8 Friend's house 2363 8785
    9 Home 85987 94772
    11 Plane 26 94798
    12 Restaurant 8081 102879
    13 School 6901 109780
    14 Someone else's house 3622 113402
    15 Store 495 113897
    16 Take out 419 114316
    17 Work 8425 122741
    18 Day camp 68 122809
    19 Day care 863 123672
    90 Other 4168 127840
    . Missing 0 127840

    DRDCFF - Combination food flag

    Variable Name:
    DRDCFF
    SAS Label:
    Combination food flag
    English Text:
    Combination food flag
    Target:
    Both males and females 0 YEARS - 150 YEARS
    Code or Value Value Description Count Cumulative Skip to Item
    0 Single component food 56969 56969
    1 Combo food 70871 127840
    . Missing 0 127840

    DRDMRUF - Flag for modified recipe use

    Variable Name:
    DRDMRUF
    SAS Label:
    Flag for modified recipe use
    English Text:
    Flag for modified recipe use
    Target:
    Both males and females 0 YEARS - 150 YEARS
    Code or Value Value Description Count Cumulative Skip to Item
    0 Non-modified recipe 120718 120718
    1 Modified recipe 7122 127840
    . Missing 0 127840

    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 127840 127840
    . Missing 0 127840

    DRDISODF - Salt adjustment flag of individual food

    Variable Name:
    DRDISODF
    SAS Label:
    Salt adjustment flag of individual food
    English Text:
    Salt adjustment flag of individual food
    Target:
    Both males and females 0 YEARS - 150 YEARS
    Code or Value Value Description Count Cumulative Skip to Item
    1 No sodium adjustment done 123345 123345
    2 Sodium value adjusted for salt use in food preparation 4495 127840
    . Missing 0 127840

    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 9000 Range of Values 127147 127147
    . Missing 693 127840

    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 4620 Range of Values 127147 127147
    . Missing 693 127840

    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 342.42 Range of Values 127147 127147
    . Missing 693 127840

    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 928.51 Range of Values 127147 127147
    . Missing 693 127840

    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 250.4 Range of Values 127147 127147
    . Missing 693 127840

    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 157.3 Range of Values 127147 127147
    . Missing 693 127840

    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 93.9 Range of Values 127147 127147
    . Missing 693 127840

    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 75.21 Range of Values 127147 127147
    . Missing 693 127840

    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 2976.03 Range of Values 127147 127147
    . Missing 693 127840

    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 88.28 Range of Values 127147 127147
    . Missing 693 127840

    DRXIVAIU - Vitamin A (IU)

    Variable Name:
    DRXIVAIU
    SAS Label:
    Vitamin A (IU)
    English Text:
    Vitamin A (IU)
    Target:
    Both males and females 0 YEARS - 150 YEARS
    Code or Value Value Description Count Cumulative Skip to Item
    0 to 162023.04 Range of Values 127147 127147
    . Missing 693 127840

    DRXIVARE - Vitamin A (RE)

    Variable Name:
    DRXIVARE
    SAS Label:
    Vitamin A (RE)
    English Text:
    Vitamin A (RE)
    Target:
    Both males and females 0 YEARS - 150 YEARS
    Code or Value Value Description Count Cumulative Skip to Item
    0 to 36203.19 Range of Values 127147 127147
    . Missing 693 127840

    DRXICARO - Carotene (RE)

    Variable Name:
    DRXICARO
    SAS Label:
    Carotene (RE)
    English Text:
    Carotene (RE)
    Target:
    Both males and females 0 YEARS - 150 YEARS
    Code or Value Value Description Count Cumulative Skip to Item
    0 to 16202.88 Range of Values 127147 127147
    . Missing 693 127840

    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 10.64 Range of Values 127147 127147
    . Missing 693 127840

    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 14.09 Range of Values 127147 127147
    . Missing 693 127840

    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 140.06 Range of Values 127147 127147
    . Missing 693 127840

    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 17.71 Range of Values 127147 127147
    . Missing 693 127840

    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 2156 Range of Values 127147 127147
    . Missing 693 127840

    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 377.26 Range of Values 127147 127147
    . Missing 693 127840

    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 1715.11 Range of Values 127147 127147
    . Missing 693 127840

    DRXIVE - Vitamin E (ATE) (mg)

    Variable Name:
    DRXIVE
    SAS Label:
    Vitamin E (ATE) (mg)
    English Text:
    Vitamin E (Alpha-Tocopherol Equivalents) (mg)
    Target:
    Both males and females 0 YEARS - 150 YEARS
    Code or Value Value Description Count Cumulative Skip to Item
    0 to 93.97 Range of Values 127147 127147
    . Missing 693 127840

    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 5685.04 Range of Values 127147 127147
    . Missing 693 127840

    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 5166.1 Range of Values 127147 127147
    . Missing 693 127840

    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 1063.14 Range of Values 127147 127147
    . Missing 693 127840

    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 96.99 Range of Values 127147 127147
    . Missing 693 127840

    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 584.57 Range of Values 127147 127147
    . Missing 693 127840

    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 28.66 Range of Values 127147 127147
    . Missing 693 127840

    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 11993.01 Range of Values 127147 127147
    . Missing 693 127840

    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 8382.87 Range of Values 127147 127147
    . Missing 693 127840

    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 1196.21 Range of Values 127147 127147
    . Missing 693 127840

    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 4120.32 Range of Values 127147 127147
    . Missing 693 127840

    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 1754.22 Range of Values 127147 127147
    . Missing 693 127840

    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 665.28 Range of Values 127147 127147
    . Missing 693 127840

    DRXIWATE - Moisture (gm)

    Variable Name:
    DRXIWATE
    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 8568 Range of Values 127147 127147
    . Missing 693 127840

    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 8.16 Range of Values 127147 127147
    . Missing 693 127840

    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 4.46 Range of Values 127147 127147
    . Missing 693 127840

    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 5.95 Range of Values 127147 127147
    . Missing 693 127840

    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 5.89 Range of Values 127147 127147
    . Missing 693 127840

    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 18.53 Range of Values 127147 127147
    . Missing 693 127840

    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 25.73 Range of Values 127147 127147
    . Missing 693 127840

    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 70.26 Range of Values 127147 127147
    . Missing 693 127840

    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 29.01 Range of Values 127147 127147
    . Missing 693 127840

    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 22.2 Range of Values 127147 127147
    . Missing 693 127840

    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 92.04 Range of Values 127147 127147
    . Missing 693 127840

    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 2.42 Range of Values 127147 127147
    . Missing 693 127840

    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 5.07 Range of Values 127147 127147
    . Missing 693 127840

    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 69.79 Range of Values 127147 127147
    . Missing 693 127840

    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 7.26 Range of Values 127147 127147
    . Missing 693 127840

    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 0.75 Range of Values 127147 127147
    . Missing 693 127840

    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 2.09 Range of Values 127147 127147
    . Missing 693 127840

    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 2.96 Range of Values 127147 127147
    . Missing 693 127840

    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 1.02 Range of Values 127147 127147
    . Missing 693 127840

    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 3.16 Range of Values 127147 127147
    . Missing 693 127840

    Appendix 1: Food Code Format File

    This dataset is a technical support file for the Individual Foods File (DRXIFF) 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 1994-98 Survey Nutrient Database. 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 format option:

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

    Proc Format CntlIn=NHANES.DRXFMT; Proc DataSets Lib=NHANES;
    Modify DRXIFF;
    FORMAT DRDIFDCD DRDIFDCD.; Quit;
    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;
    Run;

    Note that the text label is up to 60 characters long.

    For foods with modified recipes including those that are not in the USDA database (DRDMRUF=1, in the individual foods file), the USDA food codes and corresponding text descriptions were assigned for reporting purpose only. While the description expresses the basic characteristics of the food, it does not reflect the actual recipe used in the food. However, the nutrient values assigned to modified recipe foods in the dietary data files do reflect the recipe modification. Please refer to the documentation for Individual Foods File for details.