Validation of FFQ Against Food Records for Vitamin D in Qatar Population

Abstract

Background: The measurement of vitamin D nutritional status through dietary assessment is a cost effective method. Food frequency questionnaire (FFQ) is usually validated against food records (FR). There is no vitamin D specific FFQ for Qatar population Objective: The objective of this study was to develop a vitamin D centric FFQ and validate FFQ against 3-day FR for Qatar population. Methodology: A quantitative FFQ based on vitamin D containing foods consumed in Qatar was developed. Vitamin D content of foods were gathered from food labels and food composition tables from the USDA. A vitamin D content database was developed for this study purpose. Dietary intakes using FFQ and 3-day FR were collected from 62 participants. Vitamin D intakes from FFQ and 3-day FR were validated with quartile comparison and Bland-Altman (BA) tests. Results: BA plot showed an agreement between FFQ and 3-day FR vitamin D intakes. BA index was 3.23%, which is <5%, a commonly used standard for validation. Quartile correlation showed ≈73% of the subjects were within one quartile difference. Conclusion: An agreement was found between vitamin D intakes from FFQ and 3-day FR. This indicates that the FFQ can be used as a valid dietary method to assess vitamin D status in Qatar’s population.