Relative validity and reproducibility of a food frequency questionnaire to evaluate food group intakes among Jordanian children and adolescents.

Introduction studies of the impact of diet on the prevention and occurrence of diseases in all life stages require a reliable and valid dietary assessment tool for assessing dietary intake. Objectives this study aimed to develop and evaluate the relative validity and reproducibility of a culturally sensitive quantitative food frequency questionnaire (FFQ) to assess food group intake among Jordanian children and adolescents. Methods the validation study was carried out on 136 children and adolescents aged between 6 and 18 years who enrolled from selected public and private schools. Fifty of these children and adolescents participated in the reproducibility phase. Food group intake from a quantitative FFQ was compared with food group intake from 24-hour dietary recalls (24h-DRs). Four 24-HRs were collected weekly for one month. Results intraclass correlation coefficients between the two FFQs ranged from 0.18 for nuts to 0.98 for tea. De-attenuated and energy-adjusted correlations ranged from 0.08 for nuts to 0.95 for vegetable oils. On average, 46.6 % and 43.6 % of participants were ranked by the FFQ-1 and the 24h-DRs into the same quartile based on their crude and energy-adjusted food group intake, respectively. Bland-Altman plots showed a satisfactory agreement between the two methods for milk and milk products and vegetables. Conclusions the findings of this study suggested that the developed FFQ has excellent reproducibility and good relative validity for most food groups.