Relative validity of micronutrient and fiber intake assessed with two new interactive meal- and web-based food frequency questionnaires

Background: the meal- and web-based food frequency questionnaires,meal-q and minimeal-q,were developed for cost-efficient assessment of dietary intake in epidemiological studies. objective: the objective of this study was to evaluate the relative validity of micronutrient and fiber intake assessed with meal-q and minimeal-q. the reproducibility of meal-q was also evaluated. methods: a total of 163 volunteer men and women aged between 20 and 63 years were recruited from stockholm county,sweden. assessment of micronutrient and fiber intake with the 174-item meal-q was compared to a web-based 7-day weighed food record (wfr). two administered meal-q questionnaires were compared for reproducibility. the 126-item minimeal-q,developed after the validation study,was evaluated in a simulated validation by using truncated meal-q data. results: the study population consisted of approximately 80% women (129/163) with a mean age of 33 years (sd 12) who were highly educated (130/163,80% with>12 years of education) on average. cross-classification of quartiles with the wfr placed 69% to 90% in the same/adjacent quartile for meal-q and 67% to 89% for minimeal-q. bland-altman plots with the wfr and the questionnaires showed large variances and a trend of increasing underestimation with increasing intakes. deattenuated and energy-adjusted spearman rank correlations between the questionnaires and the wfr were in the range ρ=.25-.69,excluding sodium that was not statistically significant. cross-classifications of quartiles of the 2 meal-q administrations placed 86% to 97% in the same/adjacent quartile. intraclass correlation coefficients for energy-adjusted intakes were in the range of .50-.76. conclusions: with the exception of sodium,this validation study demonstrates meal-q and minimeal-q to be useful methods for ranking micronutrient and fiber intake in epidemiological studies with web-based data collection.