Key Concepts About NHANES II Data Structure

 

Data Filenames

The NHANES II (1976-80) data were released in separate files.  Each file corresponds to a different part of the survey, e.g., the medical health questionnaire for adults, the physician exam, and the laboratory assessment. The NHANES II data files were originally released as magnetic data tapes for use on mainframe computers, but can now be downloaded directly from the NHANES website. Each tape was assigned a number and this tape number has been retained as part of the downloadable filename following the prefix DU. For instance, the data filename for Anthropometry is DU5301.TXT,  the SAS Code file name is DU5301.SAS ,and the formatted SAS code filename is DU5301_F.SAS. The following table outlines the NHANES II data files.

 

View an animated explanation of the component descriptions or review that table below to see component descriptions.

NHANES II - Tape Numbers, Component Name and Abbreviation
Tape Number Abbreviation Name Description
5010 CH Medical History Questionnaire, Ages 6 months-11 years There are two Medical History Questionnaire data files corresponding to the different interviews conducted for two age categories. This one contains interview questions asked of participants 6 months-11 years of age.
5020 AH Medical History Questionnaire, Ages 12-74 years There are two Medical History Questionnaire data files corresponding to the different interviews conducted for two age categories. This one contains interview questions asked of participants 12-74 years of age.
5252 XR Chest X-Ray Examination The Chest X-Ray Exam file contains the pathology findings based on x-ray readings for participants 25-74 years old who had chest x-rays.
5301 BM Anthropometry The Anthropometry file contains anthropometric measurements taken for all participants 6 months- 74 years of age.
5302 PE Physician's Examination The Physician's Exam file contains all the examination findings and measurements, such as blood pressure taken during the physician's exam for all participants 6 months-74 years of age.
5305 SH Health History Supplement The Health History Supplement file contains interview questions on selected conditions, health behaviors, and exposures including heart disease, back and neck pain, pain in joints, mononucleosis, jaundice, hernia operations; contact with carbon tetrachloride, pesticides, disinfectants; smoking history, kidney disease, constipation or diarrhea, physical disabilities, menstrual and pregnancy history and reproductive health, and blood pressure data for participants 12-74 years of age.
5306 AU Audiometric Air Conduction Test The Audiometric Air Conduction Test file contains data for participants 4-19 years of age on audiometric tests at four frequencies.
5309 AL Allergy Skin Testing The Allergy Skin Testing file contains the results of allergy skin testing (length and width of wheal and flare at 10 minutes and 20 minutes) for the following allergens: house dust, cat, dog, ragweed, oak, rye grass, and Bermuda grass and controls. The allergy tests were conducted for participants 6-74 years of age.
5317 BQ Behavior Questionnaire The Behavior Questionnaire file contains data for participants 25-74 years of age from questions on behaviors to identify " type A” personality types which may be associated with coronary heart disease. The questions are taken from the 1965 Jenkins Activity Survey which was usually self-administered.
5411 LB Hematology and Biochemistry The Hematology and Biochemistry file contains results from analyses of blood and urine specimens taken for all participants 6 months- 74 years of age.
5701 DR Total Nutrient Intake, Food Frequency, and Other Related Dietary Data The Total Nutrient Intake, Food Frequency, and Other Related Dietary Data file contains nutrient intake information for calories and 17 nutrients for each participant. The file also contains information from the food frequency section on reported frequencies of consumption of foods from 18 food groups, of which 5 have subdivisions for a total of 26 separate categories. Other related dietary data includes information related to food consumption habits recorded on the 24-hour recall and dietary supplement forms, such as vitamin-mineral usage and special diets.
5702 MG Model Gram The Model Gram Data file is the first file of a two-file nutrient data bank. The first 119 records in this file are the acceptable FOOD MODELS or combinations of food models used to aid the respondent in recalling amounts of foods reported on the 24-hour recall form. The second file consists of 2605 foods in numeric order with designated food group number, food code number, preferred model code, appropriate gram conversion factor, and alphanumeric description. When listed by food group, the MODEL GRAM data file provided the basis for the coding manual used by dietary interviewers. In some instances, more than one food was assigned the same food code, but only when the nutrient composition for each of the foods was extremely similar.
5703 NC Nutrient Composition The Nutrient Composition Data file provides a nutrient analysis of the 2,605 foods found on the MODEL GRAM data file. Calories and 17 nutrients per 100 gram edible portion are provided for each food. Nutrient values used to update foods on this data file reflect the nutrients available in the food between 1976 and 1980. These nutrient values were obtained either from the manufacturer, or from the U.S. Department of Agriculture's revised Handbook No. 8, sections1-6 and data tape 456-3 (based on USDA Agriculture Handbook No. 456). For commercial foods that were reported ingested at least twenty times, the nutrient values reflect the most appropriate information (1980) available from the manufacturer. If the food company did not provide the needed information, nutrient values from other sources were used, where possible. Foods reported fewer than twenty times were not updated and may not reflect the most current nutrient analysis from the manufacturer.
5704 DR 24-Hour Recall, Specific Food Item The 24-Hour Recall and Specific Food Item Data file contains information on specific food items consumed by (a) ingestion period, (i.e., breakfast, lunch, dinner, and between-meal foods); (b) the time of day to the closest half hour that the food was consumed; (c) the source of intake (i.e., home, school, restaurant); and calories and 17 nutrients for each food item contributing to the day's total intake. Information is collected for the period of time midnight to midnight preceding the interview and generally reflects intakes reported on Mondays through Fridays, excluding most holidays. This is a result of the general scheduling of examinations on Tuesdays through Saturdays.
* EC ECG The electrocardiography (ECG) data file contains data on ECG tests performed for participants 25-74 years of age. These data were originally released as one of the series of data files released for the NHANES III (1988-94). Therefore, the data documentation and data file structure follow conventions used for the NHANES III data files. The data file is named NH2ECG.DAT.
** ** Hepatitis The Hepatitis data file contains data on tests for antibodies to hepatitis virus. These data files were revised to improve format and file structure for users and the data file structure follows the conventions used for the Continuous NHANES.
** ** Herpes The Herpes data file contains data on tests for antibodies to hepatitis virus. These data files were revised to improve format and file structure for users and the data file structure follows the conventions used for the Continuous NHANES.
** ** Syphilis Serological Markers The Syphilis Serological Markers data file contains data on three serologic markers for syphilis infection. These data files were revised to improve format and file structure for users and the data file structure follows the conventions used for the Continuous NHANES.

* These data were released later on CD-ROM and not released on data tape. Therefore, these variables do not have tape numbers.

** These data were released via Internet and do not have tape numbers or component name abbreviations.

 

Exceptions

Due to historic reasons, some data files were released with SAS code only, while others were released with neither SAS code nor formatted SAS code. Some recently released files are in SAS transport format which no longer require SAS code. When it is deemed necessary to re-release older NHANES data files, modern formats such as SAS transport files are usually adopted.

The following list gives you a general idea of what some of these exceptions are:

  1. Released in SAS code only (no formatted SAS code):
  2. Released with neither formatted nor SAS codes (you will have to write your own code)
  3. Released in SAS transport file (no SAS code is needed)

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