Developed and validated food frequency questionnaires in Iran: A systematic literature review

Food frequency questionnaires (FFQs) are inexpensive, easy to administer, and practical tools for dietary assessment in epidemiological studies. Several studies have investigated the validity and reproducibility of FFQs for the Iranian population. This systematic review aimed to assess the developed and validated FFQs for use in the Iranian population and compare their features and the validation studies in this regard. A comprehensive search was conducted in ISI Web of Knowledge, PubMed, Scopus, and Iranian databases without time constraints to retrieve the relevant English and non-English publications. Studies would be included if they were focused on the design and validation of FFQs in Iran. In total, 782 articles were found, 22 of which met the eligibility criteria and evaluated 18 FFQs. Validation studies had been conducted on 18 out of 20 FFQs. The median of the correlation coefficients for the comparison of the FFQ intakes and the dietary reference method by nutrients varied within the range of 0.19-0.65, indicating reasonable validity. The median of the correlation coefficients for the comparison of two FFQs by nutrients was 0.28-0.85, showing appropriate reproducibility. However, low validity was observed in some nutrients and food groups, such as egg, legumes, iron, folate, and α-tocopherol. In seven studies, biomarkers were used for the assessment of nutrient intake using an FFQ with the median correlation coefficient of -0.07-0.42. In addition, the quality of methodology was evaluated in the FFQ validation studies, with 18 out of 20 studies reporting good and excellent quality. Although the FFQs used to assess the dietary intake of the Iranian population have different features, they have acceptable validity and reproducibility. Nevertheless, some food groups and nutrients have poor validity and must be considered attentively.