AUTHOR=Eghtesad Sareh , Hekmatdoost Azita , Faramarzi Elnaz , Homayounfar Reza , Sharafkhah Maryam , Hakimi Hamid , Dehghani Ali , Moosazadeh Mahmood , Mortazavi Zinat , Pasdar Yahya , Poustchi Hossein , Willett Walter C. , Malekzadeh Reza 

TITLE=Validity and reproducibility of a food frequency questionnaire assessing food group intake in the PERSIAN Cohort Study

JOURNAL=Frontiers in Nutrition

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2023.1059870

DOI=10.3389/fnut.2023.1059870

ISSN=2296-861X

ABSTRACT=<sec id="sec1"><title>Purpose</title><p>A semi-quantitative food frequency questionnaire (FFQ) was developed for use in the Prospective Epidemiological Research Studies in IrAN (PERSIAN Cohort), investigating non-communicable disease risk factors. This study aimed to assess the validity and reproducibility of this FFQ, through food group intake.</p></sec><sec id="sec2"><title>Methods</title><p>Participants, recruited from seven PERSIAN cohort centers, completed the FFQ at the beginning of the study (FFQ1) and at the end (FFQ2), with a 12-month interval in between, during which two 24-h dietary recalls (24 h) were completed each month. Correlation coefficients of the median intake of food groups recorded by the FFQs were compared to those of the 24 h to assess validity, and the two FFQs were compared to assess reproducibility of findings.</p></sec><sec id="sec3"><title>Results</title><p>Overall, data from 978 participants were included in this validation analysis. Of the 26 food groups assessed, <italic>Tea</italic>, <italic>Sugars</italic>, <italic>Whole/Refined Grains</italic>, and <italic>Solid Fats</italic>/<italic>Oils</italic>, had the strongest correlations (0.6–0.79), while <italic>Red Meat, Chicken</italic> and <italic>Eggs</italic> showed moderate correlations (0.42–0.59). The weakest correlations observed belonged to <italic>Fresh fruit Juice</italic> and <italic>Other Meats</italic> (0.23–0.32). Reproducibility was assessed among those who completed both FFQ1 and FFQ2 (<italic>n</italic> = 848), revealing moderate to strong correlations in all food groups, ranging from 0.42 in <italic>Legumes</italic> to 0.72 in both <italic>Sugar</italic> and <italic>Sweetened Drinks.</italic></p></sec><sec id="sec4"><title>Conclusion</title><p>The PERSIAN Cohort FFQ is appropriate to rank individuals based on food group intake.</p></sec>