Relative validity and reproducibility of the CyFFQ semiquantitative food frequency questionnaire for assessing dietary intake in Cypriot adults.

ABSTRACT

BACKGROUND: Assessment of dietary intake is fundamental for evaluating the interrelationships between diet and disease. The present study aimed to develop and validate the semiquantitative Cypriot food frequency questionnaire (CyFFQ). METHODS: A 171-item paper-and-pencil semiquantitative interview-administered FFQ was developed, including local foods and culturally specific meals commonly consumed among Cypriot adults. FFQ reproducibility was assessed by comparing the energy-adjusted daily macro- and micronutrients intake at baseline (FFQ1) and 1 year later (FFQ2) using a Wilcoxon matched pairs signed rank test and intraclass correlation coefficients (ICCs) in a random sample of Cypriot adults. FFQ relative validity was evaluated by comparing the intake as estimated by FFQ2 with that obtained from the average of three 24-h recalls taken over the year between FFQ1 and FFQ2. Associations between nutrient intakes estimated using FFQ2 and the 24-h recalls were assessed using Spearman rank correlation and Bland-Altman plots were used to assess agreement between the FFQ and the 24-h recalls. RESULTS: Among eligible participants, 68 (78%) completed the study (44.1% males, aged 30.5-47.5 years). The energy-adjusted intakes of macro- and micronutrients did not significantly differ between the two FFQs, excluding magnesium. The FFQ2 and the averaged 24-h recalls were significantly correlated for most macro- and micronutrients. The median (interquartile) ICC for all macro- and micronutrients was 0.46 (0.38-0.52) (p < 0.05). Agreement was satisfactory (>30%) for most micro- and macronutrients. Bland-Altman plots also confirmed good agreement between the two methods. CONCLUSIONS: The CyFFQ is a valid and reliable tool for assessing dietary consumption in Cypriot adults.