Pilot study of the validity of food frequency questionnaires in Taiwan

Objectives: The main purpose of this study was to assess the validity of two food frequency questionnaires: the food and ingredients-based food frequency questionnaire (FIFFQ) and the meal and dish-based food frequency questionnaire (MDFFQ). The effect of energy calibration on validity was also examined. Methods: A total of 151 participants completed the 141-item MDFFQ and then the 161-item FIFFQ 5 months later. Validity was assessed by comparing the questionnaires according to 24-hour recall (24HDR) and after energy calibration. Results: The average of the correlation coefficients between the FIFFQ and 24HDR for 28 nutrients was .03, which increased to 0.25 after energy calibration; for six food groups, it was 0.17 or 0.32 after energy calibration. The average of the coefficients of the correlation between the MDFFQ and 24HDR was 0.03, which increased to 0.25 after energy calibration. Before and after energy calibration, the average percent agreement between the FIFFQ and 24HDR was 35% and 41% for 28 nutrients and was 37% and 43% for 6 food groups, respectively. The average percent agreement between the MDFFQ and 24HDR was 33% or 41% after energy calibration. The weighted kappa ranged from -0.01 to 0.40 for the FIFFQ and 24HDR and from 0.02 to 0.43 for the MDFFQ and 24HDR after energy calibration. Conclusions: The FIFFQ and MDFFQ exhibited acceptable correlations and validity after energy calibration. Therefore, the use of these food frequency questionnaires to assess dietary patterns may require energy adjustment or quantitative dietary measurements such as recall or records for calibration purposes to improve their association with outcome variables.