Development of the DHQ II Nutrient & Food Group Database
The nutrient and food
group database, created for analyzing the DHQ II, is based on a compilation
of national 24-hour dietary recall data from the National Health and Nutrition
Examination Surveys (NHANES) conducted in 2001-02, 2003-04, and 2005-06. These
24-hour dietary recall data were used to determine foods to include and portion
size units on the DHQ II.
The NHANES foods reported on 24-hour dietary recalls were placed into
cognitively and nutritionally similar food groups and analyzed for their
contribution to nutrient intakes to determine the list of foods to include.
Those food groups selected for inclusion in DHQ II include many different
individual foods recorded on recalls that are subsumed by the line item, for
example, "lasagna, stuffed shells, stuffed manicotti, ravioli, or tortellini."
The NHANES data were analyzed to provide a mean nutrient or food group value, by
gender and portion size, based on all reported intakes of the various lasagna,
stuffed shells, etc., reported on 24-hour recalls in NHANES. This produced a
single nutrient or food group value by portion size and gender for each food on
the DHQ II. The primary databases used to compute nutrient and food group
estimates are the US Department of Agriculture's Food and Nutrient
Database for Dietary Studies (FNDDS) and USDA's MyPyramid
Equivalents Database. Additional nutrients have been added from the Nutrition Data System for
Research (NDS-R) (see below).
Nutrient values were not computed separately by age group because our
research (cited below) showed that separate nutrient values by age group did not
improve estimates. However, for investigators interested in adding age-specific
values in the database, the Diet*Calc software has the flexibility to allow you
to do so. For a more detailed description of the method used to create the
values for the DHQ II database, please see:
Subar AF, Midthune D, Kulldorff M, Brown CC, Thompson FE, Kipnis V, Schatzkin A.
Evaluation of alternative approaches to assign nutrient values to food groups in food frequency questionnaires.
Am J Epidemiol 2000 Aug 1;152(3):279-86.
[View Abstract]
Nutrients from Nutrition Data System for Research (NDS-R)
The methods used to add NDS-R nutrients to the
DHQ II database are the result of the efforts of Dr. Lori Beth Dixon at New York
University and Thea Zimmerman at Westat. In the DHQ II database such nutrients
are clearly marked in the variable labels as "(NDS-R based)". The methods used
to add NDS-R nutrients to the DHQ database are described in:
Dixon LB, Zimmerman TP, Kahle LL, Subar AF.
Adding carotenoids to the NCI Diet History Questionnaire Database.
J Food Comp Anal 2003;16:269-80.
To summarize, however, these values are the result of matching NHANES food
codes to similar foods in the nutrient database of the Nutrition Data Systems
for Research (NDS-R) from the University of Minnesota, which has nutrient values
not available from NHANES. The values for the DHQ were then computed using the
data based approach described in:
Subar AF, Midthune D, Kulldorff M, Brown CC, Thompson FE, Kipnis V, Schatzkin A.
Evaluation of alternative approaches to assign nutrient values to food groups in food frequency questionnaires.
Am J Epidemiol 2000 Aug 1;152(3):279-86.
[View Abstract]
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