NHANES III was conducted in two phases, from 1988-91 and from 1992-94. Most
analyses are conducted on the combined 6-year data files from 1988-94.
Data Releases
NHANES III data were
released in separate intervals. Two specific releases contain
the majority of data of interest to most researchers – these are
Series 11, nos. 1a and 2a. There are a number of other data
releases (e.g. series 3a through 25a) which contain additional
data based upon a subsample of the survey, very specific topic
areas which were delayed in their original release, or data
files based on surplus sera projects (so data releases based on
NHANES III continue to occur).
Series 11 no. 1a contains the majority of
the data and corresponding documentation for the survey interview and
examination components. These are found in five separate data files: the NHANES
III Household Adult Data File, NHANES III Household Youth Data File, NHANES III
Examination Data File, NHANES III Laboratory Data File, and the NHANES III
Dietary Recall Data Files.
Household adult file contains survey design variables
such as weights, strata and primary sampling units, demographic variables,
and data collected through the household adult questionnaire administered to
survey participants aged 17 years and older during the household interview.
Household Youth file contains survey design variables
such as weights, strata and primary sampling units, demographic variables,
and data collected through the household youth questionnaire administered to
survey participants aged 2 months through 16 years during the household
interview.
Examination file contains information collected
through mobile examination center interviews, physical exams and dental
exams.
Laboratory file contains results from analyses of
blood and urine specimens.
Dietary recall files contain data collected through
mobile examination center interviews on dietary interview components. Most
analysts will use the dietary recall/foods files in Series 11 no. 2a
however, since they contain a small number of corrections to the files
provided in Series 11 no. 1a plus total nutrient
intake data based on the University of Minnesota Nutrition Coordinating
Center (NCC) nutrient database.
Series 11 no. 2a contains data not
available for the Series 11 no. 1a release in July 1997. The data in this
release includes electrocardiogram, dietary recall, laboratory, and
vitamin/supplements/prescription drug data.
Electrocardiogram file contains data on ECG readings
administered during the MEC examination from NHANES I (ages 25-74), II (ages
25-74), and III (ages 40 and over).
Vitamins/Supplements/Prescription Drug files contains
data collected through the household and MEC interviews on the use of
prescription drugs, vitamins, dietary supplements, and data not previously
released for the household adult and youth files, and the laboratory files.
Foods files contain dietary information available in
Series 11 no.1a plus total nutrient intake data based on the University of
Minnesota Nutrition Coordinating Center (NCC) nutrient database.
Data Files
Several of the files in Series 11 no. 1a are very large.
However, variables tend to be grouped as they were in the
questionnaires and the user would be well advised to use the
search feature to find the variables of interest to them.
Care should be taken to search both the household and the
examination
files, as some items of interest, such as blood pressure
measurements, were ascertained in both.
In the picture below, click the headings to see examples of the types of data
to be found in the various data files constituting the NHANES III data releases.
Examples of
NHANES III - Series 11 Data Files and Variables
