Table of Contents

Locator Record

Title: Dietary Interview (DRXDOC_D )
Contact Number: 1-866-441-NCHS
Years of Content: 2005 - 2006
First Published: July, 2008
Revised: NA
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject:Dietary interview component provides detailed dietary intake information from NHANES participants.
Record Source: NHANES 2005 - 2006
Survey Methodology: NHANES 2005 - 2006 is a stratified multistage probability sample of the civilian non-institutionalized population of the U.S.
Medium: NHANES Web site; SAS transport files

Component Description

The objective of the dietary interview component is to obtain detailed dietary intake information from 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. Beginning in 2005-2006, water drunk throughout the day is collected as part of the 24-hour dietary recall (see more details in the “What’s New with the 2005-2006 WWEIA Release” section). Following the dietary recall, participants are asked questions on salt use, whether the person’s intake on the previous day was usual or unusual, and whether the respondent is on any type of special diet. Survey participants 1 year or older were asked questions on frequency of fish and shellfish consumed during the past 30 days.

The dietary interview component, called What We Eat in America (WWEIA), is conducted as a partnership between the U.S. Department of Agriculture (USDA) and the U.S. Department of Health and Human Services (DHHS). Under this partnership, DHHS’ National Center for Health Statistics (NCHS) is responsible for the sample design and data collection and USDA’s Food Surveys Research Group (FSRG) is responsible for the dietary data collection methodology, maintenance of the databases used to code and process the data, and data review and processing.

All NHANES examinees are eligible for two 24-hour dietary recall interviews. The first dietary recall interview is collected in-person in the Mobile Examination Center (MEC) and the second interview is collected by telephone 3 to 10 days later.

As in previous years, two types of dietary intake data are available for the 2005-2006 survey cycle - Individual Foods files and Total Nutrient Intakes files. Each of these dietary intake data files is accompanied by a PDF file containing its documentation, codebook, and frequencies. The structure of the PDF file for the 2005-2006 dietary intake data files has been modified slightly from earlier survey years so that the documentation section of the file for each of the two types of dietary intake data files is identical.

What’s New with the 2005-2006 WWEIA Release: One of the major changes to this release is that beginning with the 2005-2006 WWEIA, the consumption of all types of water (including tap and bottled water, plain and carbonated, sweetened and unsweetened water) was collected during the 24-hour recall. As a result, each report of water intake throughout the day was collected and coded as a separate food item. These water intake items now appear in the Individual Foods file with food codes designating the type of water. As with other foods, a variable is present to indicate if the water was consumed at home or away. For bottled waters, a variable is present indicating where the water was obtained. For tap water, the variables DR1TWS and DR2TWS in the Total Nutrient Intake files indicate the main source of tap water drunk by the participant. In 2003-2004, only sweetened bottled waters were collected during the 24-hour recall and included in the Individual Foods file. Information on daily intake of non-sweetened waters (total plain water, total tap water and the source of tap water, total bottled water, and plain carbonated water) were collected after the 24-hour dietary recall and included in the Total Nutrient Intake file for 2003-2004. In 2005-2006, summary water variables that are compatible with previous data cycles are included in the Total Nutrient Intake files with the exception of plain carbonated water. These water totals (DR1_320Z, DR2_320Z, DR1_330Z, DR2_330Z, DR1BWATZ and DR2BWATZ) represent total water consumed as a beverage by itself. Therefore, they do not include the moisture content of foods and beverages (such as watermelon, coffee, lettuce) that are available for each food reported in the Individual Foods files.

The table in Appendix 1 summarizes additional changes among the 3 latest cycles of data collection.

Dietary Interview Data Files: Four data files were produced from the information collected in the dietary interview: two Individual Foods files and two Total Nutrient Intake files. Each file includes one day of intake data. The number “1” or “2” in the file name identifies the day (and mode) of the interview: 1 = first day (in-person), 2 = second day (phone). File names are the following:

File Names for Dietary Interview Data
File Day 1 Day 2
Individual Foods File DRIFF_D DR2IFF_D
TotalNutrient Intakes File DR1TOT_D DR2TOT_D

The nutrient amounts in these files reflect only nutrients obtained from foods, beverages, and water including tap and bottled water. They do not include nutrients obtained from dietary supplements, antacids, or medications.

Individual Foods Files (DR1IFF_D and DR2IFF_D): Detailed information about the types and amounts of individual foods reported by each participant, as well as amounts of nutrients from each food are included in the Individual Foods files. The names for both Day 1 and Day 2 variables are listed in Appendix 2.

Two supporting files are also included with the Individual Foods files: the Food Code Description file (DRXFCD_D) and the Modification Code Description file (DRXMCD_D). The DRXFCD_D file includes abbreviated descriptions (up to 60 characters) and complete descriptions (up to 200 characters) associated with each USDA food code identified in the Individual Foods files. The DRXMCD_D file includes descriptions (up to 200 characters) associated with each modification code identified in the Individual Foods files. Modification codes represent adjustments to predefined recipe ingredients that reflect more closely the food as described by the respondent. Appendix 3 provides SAS code examples that may be used to link the food code or the modification code description to the Individual Foods file.

The Individual Foods files include, for each interview day, one record for each food consumed by a survey participant. Each food record is sequentially numbered and contains the information listed below:

Total Nutrient Intakes Files (DR1TOT_D and DR2TOT_D): For each participant, daily total energy and nutrient intakes from foods and beverages and whether the amount of food consumed was usual, much more than usual, or much less than usual are included in the Total Nutrient Intakes files. The Day 1 file also includes information on salt use in cooking and at the table; whether the participant is currently on any kind of diet to lose weight or for other health-related reason and, if so, the type of diet; and for participants 1 year or older, information on frequency of fish and shellfish consumption. The names for both Day 1 and Day 2 variables are listed in Appendix 5.

The Total Nutrient Intakes files provide a summary record of total nutrient intakes for each individual. Each total intake record contains the following information:

Eligible Sample

All NHANES examinees are eligible for the dietary interview component. However, only examinees one year or older are eligible for the frequency of fish and shellfish consumption questions following the 24-hour recall.

Protocol and Procedure

The examination protocol and data collection methods are fully documented in the NHANES dietary interviewers procedures manuals (Centers for Disease Control and Prevention, National Health and Nutrition Examination Survey MEC In-Person Dietary Interviewers Procedure Manual, Centers for Disease Control and Prevention, National Health and Nutrition Examination Survey Phone Follow-Up Dietary Interviewer Procedure Manual).

Interviews were conducted for survey participants less than six years of age with a proxy who was generally the person most knowledgeable about the survey participant’s intake. With children ages 6 to 11, the interviews were conducted with the child and the assistance of an adult familiar with the child’s intake. 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 measuring guides (various glasses, bowls, mugs, drink boxes and bottles, household spoons, measuring cups and spoons, a ruler, thickness sticks, bean bags, and circles) was available in the MEC dietary interview room for the participant to use for reporting amounts of foods (Centers for Disease Control and Prevention, National Health and Nutrition Examination Survey Measuring Guides for the Dietary Recall Interview). Upon completion of the in-person interview, participants were given measuring cups, spoons, a ruler, and a food model booklet, which contained two-dimensional drawings of the various measuring guides available in the MEC, to use for reporting food amounts during the telephone interview. Telephone dietary interviews were collected 3 to 10 days following the MEC dietary interview but not on the same day of the week as the MEC interview. Any participant who did not have a telephone was given a toll-free number to call so that the recall could be conducted.

What We Eat in America data were collected using USDA’s dietary data collection instrument, the Automated Multiple Pass Method (AMPM) (Agricultural Research Service, USDA Automated Multiple-Pass Method for Dietary Recalls). The AMPM was designed to provide an efficient and accurate means of collecting intakes for large-scale national surveys. The AMPM is a fully computerized recall method that uses a 5-step interview outlined below:

  1. Quick List - Participant recalls all foods and beverages consumed the day before the interview (midnight to midnight).
  2. Forgotten Foods - Participant is asked about consumption of foods commonly forgotten during the Quick List step.
  3. Time and Occasion - Time and eating occasion are collected for each food.
  4. Detail Cycle - For each food, a detailed description, amount eaten, and additions to the food are collected. Eating occasions and times between eating occasions are reviewed to elicit forgotten foods.
  5. Final Probe - Additional foods not remembered earlier are collected.

The AMPM includes an extensive compilation of standardized food-specific questions and possible response options. Routing of questions is based on previous responses. The AMPM is updated yearly to reflect 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, 2004).

FSRG conducted the AMPM Validation Study to evaluate the accuracy of this dietary intake method. Completed in 2004, this extensive research project included 524 healthy, weight-stable volunteers, aged 30-69 years. The accuracy of the AMPM was evaluated by comparing reported energy intake (EI) to total energy expenditure (TEE) using the doubly labeled water technique (Moshfegh). Among the findings were that EI compared to TEE was under-reported by 11% overall and by less than 3% for normal weight subjects with body mass index (BMI) <25.

Other studies have also reported on the validity of the AMPM to measure group energy intake (EI). Blanton reported that EI was not significantly different from TEE for a sample of 20 adult females (Blanton, 2006). Rumpler and colleagues found that mean EIs were accurately reported for a sample of 12 adult males (Rumpler, 2008).

For additional information about the dietary interview component and related survey protocols, please go to the Survey Operations Manual, Consent Documents, Brochures site at:
http://www.cdc.gov/nchs/about/major/nhanes/nhanes2005-2006/current_nhanes_05_06.htm.

Quality Assurance & Quality Control

All dietary interviewers were required to complete an intensive one-week training course and to conduct supervised practice interviews before working independently in the field. Retraining sessions were conducted annually to reinforce the proper protocols and technique.

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

 

Data Processing and Editing

Interview data files were sent electronically from the field and were imported into Survey Net, a computer-assisted food coding and data management system developed by USDA (Raper, 2004).

USDA's Food and Nutrient Database for Dietary Studies, 3.0 (FNDDS 3.0), was used for processing the 2005-2006 intakes. The FNDDS includes comprehensive information that can be used to code individual foods and portion sizes reported by participants and also includes nutrient values for calculating nutrient intakes. The underlying nutrient values for FNDDS 3.0 were based on values in the USDA National Nutrient Database for Standard Reference, release 20, produced by USDA’s Nutrient Data Lab (Agricultural Research Service, USDA National Nutrient Database for Standard Reference, Release 20). FNDDS values are updated for every 2-year WWEIA, NHANES release cycle. FNDDS 3.0 corresponds with WWEIA 2005-2006. Additional information about the FNDDS and related tools is available on the Food Surveys Research Group website (Raper, 2004, Agricultural Research Service, USDA Food and Nutrient Database for Dietary Studies 3.0, Anand, 2006, Bodner-Montville, 2006, Ahuja, 2008).

Coders were required to pass a certification test after the initial training. They were routinely monitored to ensure the quality and completeness of their work. Approximately 10 percent of the coder's work was randomly selected to be independently coded by another coder. Results from the two codings were compared and adjudicated, if necessary.

After intake data were coded, various types of reviews were conducted to ensure the quality of the data. An overview of quality assurance procedures conducted during the data processing stage is available in Anand, et al. (Anand, 2006). Examples of reviews include the following:

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

Analytic Notes

Each Individual Foods file (Day 1 and Day 2) is comprised of food records. For most survey participants, there are multiple records in each file. For each Total Nutrient Intakes file (Day 1 and Day 2) there is one record for each participant. These files can be linked with other NHANES files by the respondent sequence number (SEQN).

Variable names: For data collected on both Day 1 and Day 2, variable names are differentiated by having the number “1” or “2” in the third position of the variable name to identify the collection day. For example, the USDA food code variable (in the Individual Foods File), which identifies the food reported by the participant, is named DR1IFDCD in the Day 1 file and DR2IFDCD in the Day 2 file. Appendices 2 and 5 list the Day 1 and Day 2 variable names for the Individual Foods file and the Total Nutrient Intakes file, respectively.

Names for the following variables are the same for both days in the Individual Foods file and the Total Nutrient Intakes file:

Variables with the Same Name for Both Days in the Dietary Interview Files
Day 1 and Day 2 Variable Name Label
SEQN Respondent sequence number
WTDRD1 Dietary day one sample weight
WTDR2D Dietary two-day sample weight
DRABF Breast-fed infant (either day)
DRDINT Number of days of intake

Number of days of intake: Because two days of data are included in the 2005-2006 release, a variable has been included to indicate the number of days of intake available for each participant. The variable name is DRDINT.

Dietary recall status code: A status code (DR1DRSTZ or DR2DRSTZ) is used in both the Individual Foods and Total Nutrient Intake files to indicate the quality and completeness of a survey participant's response to the dietary recall section. The codes are the following:

1 = Reliable and met the minimum criteria
For individuals with a code 1, all relevant variables associated with the 24-hour dietary recall contain a value.

2 = Not reliable or did not meet the minimum criteria
Individuals with a code 2 have incomplete records. No data on total nutrient intakes and the total number of foods reported are provided for these cases. These individuals have no records in the Individual Foods files.

3 [Code 3 is not included in the current datasets. It was only used for data from the 1999-2000 survey cycle.]

4 = Reported consuming breast milk
For infants and children who consumed human milk, there is a record in the Individual Foods files for each report of human milk. However, because amounts of human milk intake are not quantified, these records contain missing values for the amount consumed and for the amounts of energy and nutrients from human milk. Also, records of human milk have a missing value for the food source variable (DR1FS, DR2FS) and the eaten at home variable (DR1_040Z, DR2_040Z) in the Individual Foods files. Records for any other foods and beverages consumed by breast-fed infants and children are included in the Individual Foods files along with their amounts and nutrient information. Because of the missing nutrient information for human milk, no total nutrient intakes (contained in the Total Nutrient Intakes files) were computed for participants with a code 4.

A variable that identifies breast-fed children, DRABF, is included. This variable has a code of 1 if a child consumed breast milk in either intake day.

5 = Not done
This code is assigned when the dietary recall section of the interview did not take place due to various reasons (such as arrived late/left early, refusal, illness, emergency, or equipment failure). These individuals have no records in the Individual Foods files. These individuals have a record in the Total Nutrients file with values only for the following variables: the respondent sequence number (SEQN), the dietary recall status code (DR1DRSTZ or DR2DRSTZ) and for participants one year or older, the fish and shellfish questions in the DR1TOT_D file (DRD340, DRD350A-K, DRD350AQ-JQ, DRD360, DRD370A-V, and DRD370AQ-UQ)

Although there are four possible values, only codes 1 and 4 appear in the Individual Foods file. In addition to the status code described above, the variable DR1_300 and DR2_300 in the Total Nutrients file, denotes the participant's assessment of whether the amount of food he/she consumed on the recall day was usual, much more than usual, or much less than usual.

Participants who reported consuming only water: In 2001-2002 and 2003-2004, individuals who reported consuming only water had no records in the Individual Foods file for that specific day. Their dietary recall status variable for the day was coded as “1” (complete and reliable) in the Total Nutrients file, and the total number of foods and all total nutrient intake variables were coded as “0”. Values were present for other variables collected during the dietary recall.

In 2005-2006, information on all waters were collected during the 24-hour recall and reported in the Individual Foods file, including tap water and bottled water. Therefore, records are now included in the Individual Foods file for participants who consumed only water. There are 3 such individuals in the 2005-2006 datasets. Their dietary recall status variable for the day is coded as “1” (complete and reliable) in the Total Nutrients file and the total number of foods is coded based on how many times water was reported. There are 5 nutrients for the tap water and plain bottled water codes that have values greater than zero - calcium, magnesium, sodium, zinc, and copper. Individuals with just water intake and no food intake will have zero energy intake for the day. Depending on the type of analysis, these individuals may need to be excluded from the analysis.

Food source: The source of each food (where it was obtained, e.g., from a store, fast food restaurant, cafeteria) is included with the 2005-2006 release as it was for 2003-2004. The variable names are DR1FS and DR2FS and are located in the Individual Foods file. Food source information was also collected in 2002, but was not publicly released because of confidentiality issues concerning single-year data. For 2005-2006, a food source for fundraiser sales has been added to reflect a frequently reported response in the “other, specify” field; its food source code number is 26. The code descriptions for this variable are:

Code Description for Source of Food Variable
Code Description
1 Store
2 Restaurant with waiter/waitress
3 Restaurant fast food/pizza
4 Bar/tavern/lounge
5 Restaurant, no additional information
6 Cafeteria not at school
7 Cafeteria at school
8 Child care center
9 Family/adult day care center
10 Soup kitchen/shelter/food pantry facility
11 Meals on Wheels
12 Community food program – other
13 Community program, no additional information
14 Vending machine
15 Common coffee pot or snack tray
16 From someone else/gift
17 Mail order purchase
18 Residential dining facility
19 Grown or caught by you or someone you know
20 Fish caught by you or someone you know
24 Sport, recreation, or entertainment
25 Street vendor, vending truck
26 Fundraiser sales
91 Other, specify

Eating occasion: The variables DR1_030Z and DR2_030Z are located in the Individual Foods file. The code descriptions for the eating occasion variables are shown in the table below.

Code Description for Eating Occasion Variable
Code Description
1 Breakfast
2 Lunch
3 Dinner
4 Supper
5 Brunch
6 Snack
7 Drink
8 Infant feeding
9 Extended consumption
10 Desayuno
11 Almuerzo
12 Comida
13 Merienda
14 Cena
15 Entre comida
16 Botana
17 Bocadillo
18 Tentempie
19 Bebida
91 Other

Eating occasion is designated by the respondent. During the interview, a list of eating occasion names is available to the respondent for reference. However, eating occasion names are not defined for the respondent and the interpretation may differ from one person to another.

Combination foods: Foods that are eaten in combination with other foods, such as cereal with milk, are identified by a combination food type (DR1CCMTX) and a combination food number (DR1CCMNM). They are located in the Individual Foods file. About half of the foods reported in 2005-2006 were consumed in combination with other foods. The code descriptions for this variable are the following:

Code Description for Type of Combination Food Variable
Code Description
0 Non-combination food
1 Beverage w/ additions
2 Cereal w/ additions
3 Bread/baked prod w/ additions
4 Salad
5 Sandwiches
6 Soup
7 Frozen meals
8 Ice cream/frozen yogurt w/ additions
9 Dried beans and vegetable w/ additions
10 Fruit w/ additions
11 Tortilla products
12 Meat, poultry, fish
13 Lunchables®
14 Chips w/ additions
90 Other mixtures

Special diet: Information on whether the participant is currently on any kind of diet to lose weight or for other health-related reason and, if so, the type of diet, is included. The variable DRQSDIET identifies whether a participant is on a special diet. The variables DRQSDT1 through DRQSDT8 and DRQSDT91 identify the type of diet(s) that the participant is following. These variables can be found in the Total Nutrient Intakes file.

Note: A participant could report more than one type of diet, and all the responses were recorded. The variable DRQSDT1 denotes the type of diet the participant followed specifically for weight loss purposes, including a variety of low calorie diets, low carbohydrate diets, and/or high protein diets. If the participant reported being on a high protein diet for the purpose of gaining weight or muscle building instead of weight loss, the response was coded in variable DRQSDT8 (Weight gain/Muscle building diet).

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 African Americans, Mexican Americans, low income persons, 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 2005-2006 NHANES, there were 12,862 persons selected; of these 9950 were considered respondents to the MEC examination and data collection. However, only 9349 of the MEC respondents provided complete dietary intakes for Day 1. Furthermore, of those providing the Day 1 data, only 8429 provided complete dietary intakes for Day 2.

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 WWEIA 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 the 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 Day 1 dietary recall data (either alone or when Day 1 nutrient data are used in conjunction with MEC data). The set of weights WTDRD1 is applicable to the 9349 respondents with Day 1 data. Day 1 weights 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 Day 1 weights are more variable than the MEC weights, and the sample size is smaller, so estimated standard errors using Day 1 data and Day 1 weights are larger than standard errors for similar estimates based on MEC weights.

When analysis is based on both days of dietary intake, only 8429 sample persons have valid data. The NHANES protocol requires an attempt to collect the second day of dietary data at least 3 days after the first day, but the actual number of days between the two interviews is variable. A set of adjusted weights, WTDR2D, is to be used only when analysis uses both Day 1 and Day 2 dietary data. This two-day weight was constructed for the 8429 respondents by taking the Day 1 weights (WTDRD1) and further adjusting for (a) the additional non-response for the second recall and (b) for the proportion of weekend-weekday combinations of Day 1 and Day 2 recalls.

Note that all sample weights are person-level weights and each set of dietary weights should sum 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) located in the Day 1 Total Nutrient Intake File (DR1TOT_D), 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. Please also refer to the Analytic Guidelines for further details on other analytic issues at: http://www.cdc.gov/nchs/nhanes/nhanes2003-2004/analytical_guidelines.htm.

References

Appendix 1. Changes between WWEIA 2001-2002, WWEIA 2003-2004 and WWEIA 2005-2006

Changes between WWEIA 2001-2002, WWEIA 2003-2004 and WWEIA 2005-2006

Item

WWEIA 2001-2002

WWEIA 2003-2004

WWEIA 2005-2006

Number of days of intake data released on each respondent

1 day

2 days

2 days

Nutrients included

Food energy and 60

nutrients/food components

Food energy and 62 nutrients/food components. "Added vitamin E" and "Added vitamin B12" were added.

Food energy and 63 nutrients/food components. Total choline added.

Food source (Where

food obtained)

Collected only in 2002; not publicly released.

Collected and released.

Values for 25 food sources.

Collected and released.

Values for 26 food sources; added “fundraiser sales”.

Combination food types

Values for 14

combination types

Values for 15 combination types; added “chips with additions”.

Values for 15

combination types

Eating occasion names

18 values

20 values; 3 existing values modified and 2 new values.

20 values

Special diet variables

Collected only in 2002; not publicly released.

Collected and released.

Collected and released.

Water consumed

(does not include the moisture content of foods)

Total amount of non-sweetened water collected after the 24-hour recall and reported in the Total Nutrient Intake files. Minerals in tap water and plain bottled water not included.

 

Total amount of non-sweetened water collected after the 24-hour recall and reported in the Total Nutrient Intake files. Minerals in tap water and plain bottled water not included.

All waters, including tap water and bottled water, were collected during the 24-hour recall and reported in the Individual Foods file, complete with food codes, gram weights and nutrient values. Summary water variables compatible with previous data cycles are included in the Total Nutrient Intake files with the exception of plain carbonated water.

Number of intakes that include only water consumption for the day

1 intake, no records in Individual Foods file

3 intakes (1 intake in Day 1 and 2 intakes in Day 2 data), no records in Individual Foods file

3 intakes (1 intake in Day 1 and 2 intakes in Day 2 data), records are included in Individual Foods file

Eligible sample for questions on fish/ shellfish consumptions in the past 30 days

Children 1-5 years and women 16-49 years of age.

Children 1-5 years and women 16-49 years of age.

All examinees one year or older.

Appendix 2. Variables in the Individual Foods Files (DR1IFF_D and DR2IFF_D) by Position

Variables in the Individual Foods Files (DR1IFF_D and DR2IFF_D) by Position

Day 1 Name     

Day 2 Name

Variable Label

SEQN              

SEQN

Respondent sequence number

DR1ILINE

DR2ILINE

Food/Individual component number

WTDRD1

WTDRD1

Dietary day one sample weight

WTDR2D

WTDR2D

Dietary two-day sample weight

DR1DRSTZ

DR2DRSTZ

Dietary recall status

DR1EXMER

DR2EXMER

Interviewer ID code

DRABF

DRABF

Breast-fed infant (either day)

DRDINT

DRDINT

Number of days of intake

DR1DAY

DR2DAY

Intake day of the week

DR1LANG

DR2LANG

Language respondent used mostly

DR1CCMNM

DR2CCMNM

Combination food number

DR1CCMTX

DR2CCMTX

Combination food type

DR1_020

DR2_020

Time of eating occasion (HH:MM)

DR1_030Z

DR2_030Z

Name of eating occasion

DR1FS

DR2FS

Source of food

DR1_040Z

DR2_040Z

Did you eat this meal at home?

DR1IFDCD

DR2IFDCD

USDA food code

DR1MC

DR2MC

Modification code

DR1IGRMS

DR2IGRMS

Grams

DR1IKCAL

DR2IKCAL

Energy (kcal)

DR1IPROT

DR2IPROT

Protein (gm)

DR1ICARB

DR2ICARB

Carbohydrate (gm)

DR1ISUGR

DR2ISUGR

Total sugars (gm)

DR1IFIBE

DR2IFIBE

Dietary fiber (gm)

DR1ITFAT

DR2ITFAT

Total fat (gm)

DR1ISFAT

DR2ISFAT

Total saturated fatty acids (gm)

DR1IMFAT

DR2IMFAT

Total monounsaturated fatty acids (gm)

DR1IPFAT

DR2IPFAT

Total polyunsaturated fatty acids (gm)

DR1ICHOL

DR2ICHOL

Cholesterol (mg)

DR1IATOC

DR2IATOC

Vitamin E as alpha-tocopherol (mg)

DR1IATOA

DR2IATOA

Added alpha-tocopherol (Vitamin E) (mg)

DR1IRET

DR2IRET

Retinol (mcg)

DR1IVARA

DR2IVARA

Vitamin A, RAE (mcg)

DR1IACAR

DR2IACAR

Alpha-carotene (mcg)

DR1IBCAR

DR2IBCAR

Beta-carotene (mcg)

DR1ICRYP

DR2ICRYP

Beta-cryptoxanthin (mcg)

DR1ILYCO

DR2ILYCO

Lycopene (mcg)

DR1ILZ

DR2ILZ

Lutein + zeaxanthin (mcg)

DR1IVB1

DR2IVB1

Thiamin (Vitamin B1) (mg)

DR1IVB2

DR2IVB2

Riboflavin (Vitamin B2) (mg)

DR1INIAC

DR2INIAC

Niacin (mg)

DR1IVB6

DR2IVB6

Vitamin B6 (mg)

DR1IFOLA

DR2IFOLA

Total folate (mcg)

DR1IFA

DR2IFA

Folic acid (mcg)

DR1IFF

DR2IFF

Food folate (mcg)

DR1IFDFE

DR2IFDFE

Folate, DFE (mcg)

DR1ICHL

DR2ICHL

Total choline (mg)

DR1IVB12

DR2IVB12

Vitamin B12 (mcg)

DR1IB12A

DR2IB12A

Added vitamin B12 (mcg)

DR1IVC

DR2IVC

Vitamin C (mg)

DR1IVK

DR2IVK

Vitamin K (mcg)

DR1ICALC

DR2ICALC

Calcium (mg)

DR1IPHOS

DR2IPHOS

Phosphorus (mg)

DR1IMAGN

DR2IMAGN

Magnesium (mg)

DR1IIRON

DR2IIRON

Iron (mg)

DR1IZINC

DR2IZINC

Zinc (mg)

DR1ICOPP

DR2ICOPP

Copper (mg)

DR1ISODI

DR2ISODI

Sodium (mg)

DR1IPOTA

DR2IPOTA

Potassium (mg)

DR1ISELE

DR2ISELE

Selenium (mcg)

DR1ICAFF

DR2ICAFF

Caffeine (mg)

DR1ITHEO

DR2ITHEO

Theobromine (mg)

DR1IALCO

DR2IALCO

Alcohol (gm)

DR1IMOIS

DR2IMOIS

Moisture (gm)

DR1IS040

DR2IS040

SFA 4:0 (Butanoic) (gm)

DR1IS060

DR2IS060

SFA 6:0 (Hexanoic) (gm)

DR1IS080

DR2IS080

SFA 8:0 (Octanoic) (gm)

DR1IS100

DR2IS100

SFA 10:0 (Decanoic) (gm)

DR1IS120

DR2IS120

SFA 12:0 (Dodecanoic) (gm)

DR1IS140

DR2IS140

SFA 14:0 (Tetradecanoic) (gm)

DR1IS160

DR2IS160

SFA 16:0 (Hexadecanoic) (gm)

DR1IS180

DR2IS180

SFA 18:0 (Octadecanoic) (gm)

DR1IM161

DR2IM161

MFA 16:1 (Hexadecenoic) (gm)

DR1IM181

DR2IM181

MFA 18:1 (Octadecenoic) (gm)

DR1IM201

DR2IM201

MFA 20:1 (Eicosenoic) (gm)

DR1IM221

DR2IM221

MFA 22:1 (Docosenoic) (gm)

DR1IP182

DR2IP182

PFA 18:2 (Octadecadienoic) (gm)

DR1IP183

DR2IP183

PFA 18:3 (Octadecatrienoic) (gm)

DR1IP184

DR2IP184

PFA 18:4 (Octadecatetraenoic) (gm)

DR1IP204

DR2IP204

PFA 20:4 (Eicosatetraenoic) (gm)

DR1IP205

DR2IP205

PFA 20:5 (Eicosapentaenoic) (gm)

DR1IP225

DR2IP225

PFA 22:5 (Docosapentaenoic) (gm)

DR1IP226

DR2IP226

PFA 22:6 (Docosahexaenoic) (gm)

 

 

Appendix 3. Adding Food Code Descriptions or Modification Code Descriptions to Your Files

Two technical support files are included with the Individual Foods files: the Food Code Description file (DRXFCD_D) and the Modification Code Description file (DRXMCD_D).

The DRXFCD_D file includes abbreviated descriptions (up to 60 characters) and complete descriptions (up to 200 characters) associated with each USDA food code identified in the Individual Foods files. The DRXMCD_D file includes descriptions associated with each modification code identified in the Individual Foods files.

The Food Code Description file (DRXFCD_D) contains three variables:

DRDIFDCD a numeric value corresponding to DR1IFDCD in the file
DR1IFF_D or DR2IFDCD in the file DR2IFF_D;
DRXFCSD a short description (up to 60 characters) of the food code.
DRXFCLD a long description (up to 200 characters) of the food code.

The Modification Code Description file (DRXMCD_D) contains two variables:

DRDMC a numeric value corresponding to DR1MC in the file DR1IFF_D or
DR2MC in the file DR2IFF_D;
DRMCD a description (up to 200 characters) of the modification code.

The following SQL code is an example of appending the modifications code description (here called DR1MCD) to one of the Individual Foods files. This code is for SAS® Proc SQL. Other SQL implementations may be different. This same technique may be used for the Food Code Description file as well.

create table dr1iff_d_plus as
select a.*,b.drxmcd as dr1mcd
from nhanes.dr1iff_d a
left join
nhanes.drxmcd_d b
on a.dr1mc = b.drxmc
order by seqn , dr1iline;

SAS® users may wish to use Proc Format to assign labels to the food codes or to the modification codes. The following example assigns a permanent format to the food code based on the short description. It is assumed that the user has stored the Individual Foods files and the Food Code Description file in a library called NHANES and wishes to store the formats there as well.

Options FmtSearch = (NHANES);

Data DRXFMT;
Set NHANES.DRXFCD_D;
Retain FMTNAME 'DRIFDCD';
Rename DRDIFDCD = Start;
Rename DRXFCSD = Value;
Drop DRXFCLD; Run;

Proc Format CntlIn= DRXFMT
Library=NHANES;
Run;

Proc DataSets Lib=NHANES;
Modify DR1IFFC;
Format DR1IFDCD DRDIFDCD.;
Modify DR2IFFC;
Format DR2IFDCD DRDIFDCD.;
Quit;

SAS® is a registered trademark of SAS Institute, Inc.

Appendix 4. List of Nutrients/Food Components (Unit)

Energy and Macronutrients

Food energy (kcal)
Protein (g)
Carbohydrate (g)
Fat, total (g)
Alcohol (g)

Sugars, total (g)
Dietary fiber, total (g)
Water (moisture) (g)*

Saturated fatty acids, total (g)
Monounsaturated fatty acids, total (g)
Polyunsaturated fatty acids, total (g)
Cholesterol (mg)

Individual fatty acids:
4:0 (g)
6:0 (g)
8:0 (g)
10:0 (g)
12:0 (g)
14:0 (g)
16:0 (g)
18:0 (g)
16:1 (g)
18:1 (g)
20:1 (g)
22:1 (g)
18:2 (g)
18:3 (g)
18:4 (g)
20:4 (g)
20:5 n-3 (g)
22:5 n-3 (g)
22:6 n-3 (g)

Vitamins, Minerals, and Other Components

Vitamin A as retinol activity equivalents (µg)
Retinol (µg)

Carotenoids:
Carotene, alpha (µg)
Carotene, beta (µg)
Cryptoxanthin, beta (µg)
Lycopene (µg)
Lutein + zeaxanthin (µg)

Vitamin E as alpha-tocopherol (mg)
Added vitamin E as alpha-tocopherol (mg)
Vitamin K as phylloquinone (µg)
Vitamin C (mg)
Thiamin (mg)
Riboflavin (mg)
Niacin (mg)
Vitamin B-6 (mg)
Folate, total (µg)
Folate as dietary folate equivalents (µg)
Folic acid (µg)
Food folate (µg)
Choline, total (mg)
Vitamin B-12 (µg)
Added vitamin B-12 (µg)

Calcium (mg)
Iron (mg)
Magnesium (mg)
Phosphorus (mg)
Potassium (mg)
Sodium (mg)
Zinc (mg)
Copper (mg)
Selenium (µg)
Caffeine (mg)
Theobromine (mg)

* Value reflects moisture present in all foods, beverages, and water consumed as a beverage (variables DR1IMOIS, DR2IMOIS, DR1TMOIS, DR2TMOIS)

Appendix 5. Variables in the Total Nutrient Intakes Files (DR1TOT_D and DR2TOT_D) by Position

Variables in the Total Nutrient Intakes Files (DR1TOT_D and DR2TOT_D) by Position

Day 1 Name

Day 2 Name

Variable Label

SEQN

SEQN

Respondent sequence number

WTDRD1

WTDRD1

Dietary day one sample weight

WTDR2D

WTDR2D

Dietary two-day sample weight

DR1DRSTZ

DR2DRSTZ

Dietary recall status

DR1EXMER

DR2EXMER

Interviewer ID code

DRABF

DRABF

Breast-fed infant (either day)

DRDINT

DRDINT

Number of days of intake

DR1DAY

DR2DAY

Intake day of the week

DR1LANG

DR2LANG

Language respondent used mostly

DR1MNRSP

DR2MNRSP

Main respondent for this interview

DR1HELPD

DR2HELPD

Helped in responding for this interview

DBQ095Z

N/A

Type of table salt used

DBD100

N/A

How often add salt to food at table

DRQSPREP

N/A

Salt used in preparation?

DRQSDIET

N/A

On special diet?

DRQSDT1

N/A

Weight loss/Low cal/Low carb/Hi pro diet

DRQSDT2

N/A

Low fat/Low cholesterol diet

DRQSDT3

N/A

Low salt/Low sodium diet

DRQSDT4

N/A

Sugar free/Low sugar diet

DRQSDT5

N/A

Low fiber diet

DRQSDT6

N/A

High fiber diet

DRQSDT7

N/A

Diabetic diet

DRQSDT8

N/A

Weight gain/Muscle building diet

DRQSDT91

N/A

Other special diet

DR1TNUMF

DR2TNUMF

Number of foods reported

DR1TKCAL

DR2TKCAL

Energy (kcal)

DR1TPROT

DR2TPROT

Protein (gm)

DR1TCARB

DR2TCARB

Carbohydrate (gm)

DR1TSUGR

DR2TSUGR

Total sugars (gm)

DR1TFIBE

DR2TFIBE

Dietary fiber (gm)

DR1TTFAT

DR2TTFAT

Total fat (gm)

DR1TSFAT

DR2TSFAT

Total saturated fatty acids (gm)

DR1TMFAT

DR2TMFAT

Total monounsaturated fatty acids (gm)

DR1TPFAT

DR2TPFAT

Total polyunsaturated fatty acids (gm)

DR1TCHOL

DR2TCHOL

Cholesterol (mg)

DR1TATOC

DR2TATOC

Vitamin E as alpha-tocopherol (mg)

DR1TATOA

DR2TATOA

Added alpha-tocopherol (Vitamin E) (mg)

DR1TRET

DR2TRET

Retinol (mcg)

DR1TVARA

DR2TVARA

Vitamin A, RAE (mcg)

DR1TACAR

DR2TACAR

Alpha-carotene (mcg)

DR1TBCAR

DR2TBCAR

Beta-carotene (mcg)

DR1TCRYP

DR2TCRYP

Beta-cryptoxanthin (mcg)

DR1TLYCO

DR2TLYCO

Lycopene (mcg)

DR1TLZ

DR2TLZ

Lutein + zeaxanthin (mcg)

DR1TVB1

DR2TVB1

Thiamin (Vitamin B1) (mg)

DR1TVB2

DR2TVB2

Riboflavin (Vitamin B2) (mg)

DR1TNIAC

DR2TNIAC

Niacin (mg)

DR1TVB6

DR2TVB6

Vitamin B6 (mg)

DR1TFOLA

DR2TFOLA

Total folate (mcg)

DR1TFA

DR2TFA

Folic acid (mcg)

DR1TFF

DR2TFF

Food folate (mcg)

DR1TFDFE

DR2TFDFE

Folate, DFE (mcg)

DR1TCHL

DR2TCHL

Total choline (mg)

DR1TVB12

DR2TVB12

Vitamin B12 (mcg)

DR1TB12A

DR2TB12A

Added vitamin B12 (mcg)

DR1TVC

DR2TVC

Vitamin C (mg)

DR1TVK

DR2TVK

Vitamin K (mcg)

DR1TCALC

DR2TCALC

Calcium (mg)

DR1TPHOS

DR2TPHOS

Phosphorus (mg)

DR1TMAGN

DR2TMAGN

Magnesium (mg)

DR1TIRON

DR2TIRON

Iron (mg)

DR1TZINC

DR2TZINC

Zinc (mg)

DR1TCOPP

DR2TCOPP

Copper (mg)

DR1TSODI

DR2TSODI

Sodium (mg)

DR1TPOTA

DR2TPOTA

Potassium (mg)

DR1TSELE

DR2TSELE

Selenium (mcg)

DR1TCAFF

DR2TCAFF

Caffeine (mg)

DR1TTHEO

DR2TTHEO

Theobromine (mg)

DR1TALCO

DR2TALCO

Alcohol (gm)

DR1TMOIS

DR2TMOIS

Moisture (gm)

DR1TS040

DR2TS040

SFA 4:0 (Butanoic) (gm)

DR1TS060

DR2TS060

SFA 6:0 (Hexanoic) (gm)

DR1TS080

DR2TS080

SFA 8:0 (Octanoic) (gm)

DR1TS100

DR2TS100

SFA 10:0 (Decanoic) (gm)

DR1TS120

DR2TS120

SFA 12:0 (Dodecanoic) (gm)

DR1TS140

DR2TS140

SFA 14:0 (Tetradecanoic) (gm)

DR1TS160

DR2TS160

SFA 16:0 (Hexadecanoic) (gm)

DR1TS180

DR2TS180

SFA 18:0 (Octadecanoic) (gm)

DR1TM161

DR2TM161

MFA 16:1 (Hexadecenoic) (gm)

DR1TM181

DR2TM181

MFA 18:1 (Octadecenoic) (gm)

DR1TM201

DR2TM201

MFA 20:1 (Eicosenoic) (gm)

DR1TM221

DR2TM221

MFA 22:1 (Docosenoic) (gm)

DR1TP182

DR2TP182

PFA 18:2 (Octadecadienoic) (gm)

DR1TP183

DR2TP183

PFA 18:3 (Octadecatrienoic) (gm)

DR1TP184

DR2TP184

PFA 18:4 (Octadecatetraenoic) (gm)

DR1TP204

DR2TP204

PFA 20:4 (Eicosatetraenoic) (gm)

DR1TP205

DR2TP205

PFA 20:5 (Eicosapentaenoic) (gm)

DR1TP225

DR2TP225

PFA 22:5 (Docosapentaenoic) (gm)

DR1TP226

DR2TP226

PFA 22:6 (Docosahexaenoic) (gm)

DR1_300

DR2_300

Compare food consumed yesterday to usual

DR1_320Z

DR2_320Z

Total plain water drank yesterday (gm)

DR1_330Z

DR2_330Z

Total tap water drank yesterday (gm)

DR1BWATZ

DR2BWATZ

Total bottled water drank yesterday (gm)

DR1TWS

DR2TWS

Tap water source

DRD340

N/A

Shellfish eaten during past 30 days

DRD350A

N/A

Clams eaten during past 30 days

DRD350AQ

N/A

# of times clams eaten in past 30 days

DRD350B

N/A

Crabs eaten during past 30 days

DRD350BQ

N/A

# of times crabs eaten in past 30 days

DRD350C

N/A

Crayfish eaten during past 30 days

DRD350CQ

N/A

# of times crayfish eaten past 30 days

DRD350D

N/A

Lobsters eaten during past 30 days

DRD350DQ

N/A

# of times lobsters eaten past 30 days

DRD350E

N/A

Mussels eaten during past 30 days

DRD350EQ

N/A

# of times mussels eaten in past 30 days

DRD350F

N/A

Oysters eaten during past 30 days

DRD350FQ

N/A

# of times oysters eaten in past 30 days

DRD350G

N/A

Scallops eaten during past 30 days

DRD350GQ

N/A

# of times scallops eaten past 30 days

DRD350H

N/A

Shrimp eaten during past 30 days

DRD350HQ

N/A

# of times shrimp eaten in past 30 days

DRD350I

N/A

Other shellfish eaten past 30 days

DRD350IQ

N/A

# of times other shellfish eaten

DRD350J

N/A

Other unknown shellfish eaten past 30 days

DRD350JQ

N/A

# of times other unknown shellfish eaten

DRD350K

N/A

Refused on shellfish eaten past 30 days

DRD360

N/A

Fish eaten during past 30 days

DRD370A

N/A

Breaded fish products eaten past 30 days

DRD370AQ

N/A

# of times breaded fish products eaten

DRD370B

N/A

Tuna eaten during past 30 days

DRD370BQ

N/A

# of times tuna eaten in past 30 days

DRD370C

N/A

Bass eaten during past 30 days

DRD370CQ

N/A

# of times bass eaten in past 30 days

DRD370D

N/A

Catfish eaten during past 30 days

DRD370DQ

N/A

# of times catfish eaten in past 30 days

DRD370E

N/A

Cod eaten during past 30 days

DRD370EQ

N/A

# of times cod eaten in past 30 days

DRD370F

N/A

Flatfish eaten during past 30 days

DRD370FQ

N/A

# of times flatfish eaten past 30 days

DRD370G

N/A

Haddock eaten during past 30 days

DRD370GQ

N/A

# of times haddock eaten in past 30 days

DRD370H

N/A

Mackerel eaten during past 30 days

DRD370HQ

N/A

# of times mackerel eaten past 30 days

DRD370I

N/A

Perch eaten during past 30 days

DRD370IQ

N/A

# of times perch eaten in past 30 days

DRD370J

N/A

Pike eaten during past 30 days

DRD370JQ

N/A

# of times pike eaten in past 30 days

DRD370K

N/A

Pollock eaten during past 30 days

DRD370KQ

N/A

# of times pollock eaten in past 30 days

DRD370L

N/A

Porgy eaten during past 30 days

DRD370LQ

N/A

# of times porgy eaten in past 30 days

DRD370M

N/A

Salmon eaten during past 30 days

DRD370MQ

N/A

# of times salmon eaten in past 30 days

DRD370N

N/A

Sardines eaten during past 30 days

DRD370NQ

N/A

# of times sardines eaten past 30 days

DRD370O

N/A

Sea bass eaten during past 30 days

DRD370OQ

N/A

# of times sea bass eaten past 30 days

DRD370P

N/A

Shark eaten during past 30 days

DRD370PQ

N/A

# of times shark eaten in past 30 days

DRD370Q

N/A

Swordfish eaten during past 30 days

DRD370QQ

N/A

# of times swordfish eaten past 30 days

DRD370R

N/A

Trout eaten during past 30 days

DRD370RQ

N/A

# of times trout eaten in past 30 days

DRD370S

N/A

Walleye eaten during past 30 days

DRD370SQ

N/A

# of times walleye eaten in past 30 days

DRD370T

N/A

Other fish eaten during past 30 days

DRD370TQ

N/A

# of times other fish eaten past 30 days

DRD370U

N/A

Other unknown fish eaten in past 30 days

DRD370UQ

N/A

# of times other unknown fish eaten

DRD370V

N/A

Refused on fish eaten past 30 days