Evaluation of a web-based, pictorial diet history questionnaire

To develop and evaluate a pictorial, web-based version of the NCI diet history questionnaire (Web-PDHQ).

The Web-PDHQ and paper version of the DHQ (Paper-DHQ) were administered 4 weeks apart with 218 participants randomised to order. Dietary data from the Web-PDHQ and Paper-DHQ were validated using a randomly selected 4 d food record recording period (including a weekend day) and two randomly selected 24 h dietary recalls during the 4 weeks intervening between these two diet history administrations.

Research office in Reston, VA, USA.

Computer-literate men and women recruited through newspaper advertisements.

Mean correlation of energy and the twenty-five examined nutrients between the Web-PDHQ and Paper-DHQ was 0.71 and 0.51, unadjusted and energy-adjusted by the residual method, respectively. Moderate mean correlations (unadjusted 0.41 and 0.38; energy-adjusted 0.41 and 0.34) were obtained between both the Web-PDHQ and Paper-DHQ with the 4 d food record on energy and nutrients, but the correlations between the Web-PDHQ and Paper-DHQ with the 24 h recalls were modest (unadjusted 0.31 and 0.29; energy-adjusted 0.37 and 0.26). A subset of participants (n 48) completing the Web-PDHQ at the initial visit performed a retest on the same questionnaire 1 week later to determine repeatability, and the unadjusted mean correlation was 0.82.

These data indicate that the Web-PDHQ has comparable repeatability and validity to the Paper-DHQ but did not improve the relationship of the DHQ to other food intake measures (e.g. food records, 24 h recall).