Cross-Cultural Validity of a Dietary Questionnaire for Studying Dental Caries in Japanese Children

This study examines the cross-cultural validity of the Japanese version of the Food Frequency Questionnaire (FFQ), designed for studies on dental caries to assess dietary intake in Japanese children. Parent-reported dietary data were collected (274 children, 3–6 years old) using the 38-item FFQ, whose reliability and validity have been demonstrated in adults. Factor analysis was used to determine dimensionality. Dietary cariogenicity scores were compared with the levels of plaque mutans streptococci, and the decayed, missing, and filled teeth (dmft) index to evaluate the criterion validity using Pearson’s correlation coefficient (r) and the Kruskal–Wallis test. The FFQ showed good criterion validity, assessed through its relationship with the dmft index (r = 0.119; p = 0.05) and Dentocult SM score (r = 0.124; p = 0.04). Factor analysis revealed six questionnaire subscales. Internal consistency was from low to acceptable (Cronbach’s alpha = 0.64 for the total scale, 0.39–0.53 for each subscale). Children with a higher SM score were more likely to have higher dietary cariogenicity scores (p = 0.01; Kruskal–Wallis test). These results confirm the validity of the Japanese version of the FFQ for children, which can be used to track dietary structure dynamics regarding cariogenicity from childhood to adulthood.