Background of the Diet History Questionnaire
The Diet History Questionnaire (DHQ) is a food frequency questionnaire (FFQ) developed by staff at the Risk Factor Monitoring and Methods Branch (RFMMB). This FFQ consists of 124 food items and includes both portion size and dietary supplement questions. It takes about 1 hour to complete and was designed, based on cognitive research findings, to be easy to use.
Data show that the DHQ provides reasonable nutrient estimates, and two studies have been conducted to assess its validity. The first, using a checklist approach, showed that many of the cognitive improvements introduced in the DHQ provided a better measure of frequency than the 1992 Block FFQ. The second validation, which compared the DHQ to two FFQs that were widely used at the time the study was conducted (the 1995 Block FFQ and the "purple version" of the Willett FFQ), showed the DHQ to be as good as or superior to those instruments for most nutrients (see Eating at America's Table Study).
The food list and nutrient database used with the DHQ are based on national dietary data (USDA's 1994-96 Continuing Survey of Food Intakes by Individuals [CSFII], available from the USDA Food Surveys Research Group).
DHQ-1 is the current version of the questionnaire distributed by the NCI. You may analyze DHQ data with the Diet*Calc software developed by the NCI. Diet*Calc may be used to analyze data files from both DHQ-1 and modified versions of the questionnaire. However, certain guidelines (described in the program's help system) must be followed when making modifications.
To use Diet*Calc, an ASCII text file containing data from completed DHQs must be created from paper-based forms or obtained from DHQ*Web. Diet*Calc will interpret the DHQ data to provide nutrient and food group intake estimates.