The DHQ instrument is currently in use in several NCI epidemiological studies such as The Prostate, Lung, Colorectal, and Ovarian Screening Trial (PLCO) and The Agricultural Health Study (AHS). Data show that the instrument provides reasonable nutrient estimates, and three studies were conducted to assess its validity/calibration.
The first validation used a checklist approach. The resulting data showed that most of the cognitive enhancements incorporated in the DHQ were an improvement over the 1992 NCI/Block questionnaire for frequency.
Thompson FE, Subar AF, Brown CC, Smith AF, Sharbaugh CO, Jobe JB, Mittl B, Gibson JT, Ziegler RG. Cognitive research enhances accuracy of food frequency questionnaire reports: results of an experimental validation study. J Am Diet Assoc 2002 Feb;102(2):212-25.
The second validation, conducted in 1997-1998, compared the DHQ instrument to two FFQs available at that time -- the 1995 Block and Willett (purple version) food frequency questionnaires. The validation used four 24-hour dietary recalls (one in each season) as reference data. The study showed the DHQ to be as good as or superior to these Block and Willett instruments for most nutrients. (Please note: The Block and Willett questionnaires used in this validation are not the current versions of these FFQs.)
Subar AF, Thompson FE, Kipnis V, Midthune D, Hurwitz P, McNutt S, McIntosh A, Rosenfeld S. Comparative Validation of the Block, Willett, and National Cancer Institute Food Frequency Questionnaires: The Eating at America's Table Study. Am J Epidemiol 2001;154:1089-99.
The third validation study compares intake of absolute energy and protein estimated on the DHQ with unbiased biomarkers of intake, doubly labeled water (for energy expenditure) and urinary nitrogen (for protein). The Observing Protein and Energy Nutrition (OPEN) Study showed significant underreporting and measurement error for the DHQ.
Subar AF, Kipnis V, Troiano RP, Midthune D, Schoeller DA, Bingham S, Sharbaugh CO, Trabulsi J, Runswick S, Ballard-Barbash R, Sunshine J, Schatzkin A. Using intake biomarkers to evaluate the extent of dietary misreporting in a large sample of adults: the OPEN study. Am J Epidemiol. 2003;158(1):1-13.
Kipnis V, Subar AF, Midthune D, Freedman SL, Ballard-Barbash R, Troiano RP, Bingham S, Schoeller DA, Schatzkin A, Carroll RJ. Structure of dietary measurement error: results of the OPEN biomarker study. Am J Epidemiol. 2003;158(1):14-21.