Validity and Reliability of Semi-Quantitative eFFQ for Hong Kong Chinese Pregnant Women

Abstract

Background: Pregnancy is an important period for delivering nutrition to the fetus and thus maternal diet remains one of the essential factors in determining the potentials of the newborn. Food Frequency Questionnaire (FFQ) is a classical tool for dietary assessment at the population scale. Instead of printed forms, several electronic FFQs (eFFQ) are being used as a cost-effective tool for data collection in large scale studies in Western countries. The present study aims to examine the validity and the reliability of an eFFQ developed for pregnant women in Hong Kong. Methods: The previously validated version of printed FFQ among Chinese population in Hong Kong was first compared against 3-day food record in the validation phase, and was later tested against eFFQ in the reliability phase. Intra-Class Correlations (ICC) between two assessment tools were calculated. The level of agreement was evaluated using Bland-Altman method and crossclassification into quartiles of daily intakes. Results: The mean percentages of participants being classified in the same or adjacent quantiles were 71.4% for nutrients and 72.4% for food groups in validation test, and 76.2% for nutrients and 69.6% for food groups in reliability test. Bias in Bland-Altman plots was found to be mild in higher or lower intakes in both nutrients and food groups. Conclusions: Both cross-classification and Bland-Altman methods suggest satisfactory agreement of the eFFQ with the validated paper FFQ. It is shown to be a reliable tool to measure dietary intake of Chinese pregnant women in Hong Kong.