Validity and Reproducibility of a Semi-quantitative Multiple-choice Food Frequency Questionnaire in Adults Living in Central Iran

Abstract

Background: To the best of our knowledge, no study has tried to develop and validate a multiple-choice food-based FFQ in Iran using weighed dietary records.This study aimed to investigate the validity and reproducibility of a multiple-choice semi-quantitative food frequency questionnaire (SQ-FFQ)in adults living in central Iran.Methods: Participants attended a large long-term clinical trial were asked to complete three SQ-FFQs by interview, and nine 3-day weighed dietary records (WDRs), over nine months.They provided two blood samples to assess serum calcium, magnesium, zinc, and vitamin C levels.The Pearson and intraclass correlation coefficients (ICC) were calculated to assess reproducibility and validity. The degree of misclassification was explored by using a contingency table of quartiles which is compare the information between third FFQ and WDRs. The method of triads was incorporated to assess validity coefficients between estimated intakes using third FFQ, WDRs, and biochemical markers and assumed true intakes.Results: A total of180 adults aged 48.9±8.4 years completed the study. Compared to WDRs, FFQs overestimated all nutrients intakes except for iron. The median Pearson correlation coefficient was 0.31, 0.44, and 0.38 for FFQ1-FFQ2, FFQ1-FFQ3 and FFQ2-FFQ3, respectively andICC ranged from 0.43 (thiamin) to 0.73 (vitamin D, median: 0.56). The de-attenuated, age, sex, and education adjusted correlation coefficients ranged from 0.01 for vitamin A to 0.40 for vitamin B12 and -0.05 for vitamin A to 0.41 for manganese (median: 0.17 and 0.26) for FFQ1-WDR and FFQ3-WDR, respectively.The medianexact agreement and complete disagreement between FFQ3 and WDRs were 33% and 6%, respectively.The FFQ3validity coefficientsfor vitamin C, calcium, magnesium, and zinc were 0.13, 0.62, 0.89, and 0.66, respectively, using the triads method.Conclusions: The SQ-FFQseems to be an acceptable tool to assess the long-term dietary intake for future large-scale studies in this population.

The Association Between Major Dietary Patterns and Severe Mental Disorders Among a Large Sample of Adults Living in Central Iran: Baseline Data of YaHS-TAMYZ Cohort Study

“…The dietary assessment in TAMYZ was done by using a 178-item semi-quantitative multiple-choice FFQ which showed an acceptable validity and reliability [27]. For each food item, participants were asked to report the i) frequency of food consumption in the past year based on 10 multiple-choice frequency response categories varying from 'never or less than once a month' to '10 or more times per day', and ii) amount of food consumed each time (portion size).…”

A comparison of principal component analysis, partial least-squares, and reduced-rank regressions in the identification of dietary patterns associated with hypertension: YaHS-TAMYZ and Shahedieh cohort studies

“…Participants were asked by trained interviewers to report the frequency of food item intake during the past year by answering 10-multiple-choice frequency responses ranging from "never or less than once a month" to "10 or more times per day." Moreover, the FFQ had five choices for portion size for estimating the intake of each food item (18). In Shahedieh study, dietary intake information was collected by a semi-quantitative open-ended FFQ based on 134-items through face-to-face interviews with the participants.…”