Reproducibility of a Semi-quantitative Food Frequency Questionnaire in Japanese Female Dietitians

Objective: To examine reproducibility of assessed intake of foods and nutrients according to a semi-quantitative food frequency questionnaire (SQFFQ) in Japanese female dietitians. Subjects and Methods: An SQFFQ was self-administered to 106 (21 male and 85 female) Japanese dietitians in Aichi prefecture in autumn 1996 and the same questionnaire was repeated in autumn 1997. Reproducibility was evaluated in terms of consumption of 15 foods and energy and 30 macro- and micro-nutrients based on the SQFFQ from 84 Japanese female dietitians. Results: For intake of foods, Pearson’s correlation coefficients (CCs) with log-transformation and energy adjustment (minimum - median - maximum) ranged from 0.35 (beverages) - 0.61 - 0.71 (dairy products). ANOVA intraclass correlation coefficients (ICCs) with log-transformation and energy adjustment ranged from 0.49 (beverages) - 0.74 - 0.82 (dairy products). Spearman’s rank CCs with energy adjustment ranged from 0.43 (confectionery) - 0.57 - 0.76 (dairy products). Weighted kappa statistics with energy adjustment ranged from 0.34 (confectionery) - 0.49 - 0.71 (dairy products). For consumption of nutrients, Pearson’s CCs with log-transformation and energy adjustment ranged from 0.23 (zinc) - 0.55 - 0.74 (insoluble dietary fiber). ANOVA ICCs with log-transformation and energy adjustment ranged from 0.37 (zinc) - 0.70 - 0.84 (insoluble dietary fiber). Spearman’s rank CCs with energy adjustment ranged from 0.25 (zinc) - 0.56 - 0.74 (magnesium). Weighted kappa statistics with energy adjustment ranged from 0.25 (zinc) - 0.50 - 0.68 (insoluble dietary fiber). Conclusions: Substantially high reproducibility of consumption of foods and nutrients was attained from an SQFFQ self-administered to Japanese female dietitians.