Abstract
OBJECTIVES: The aim of the study was to assess the relative validity of a semi-quantitative FFQ (SFFQ) which measures the usual dietary intake of 3-year-old children. DESIGN: The children's daily dietary intake was measured using the SFFQ. The average intake of three 24 h dietary recalls (24hDR) was calculated as a reference method. Wilcoxon's rank test and Spearman's rank-correlation coefficient were used to compare nutrient intakes assessed by both methods. The level of agreement between the SFFQ and the repeated 24hDR was determined by the Bland-Altman method. To assess the agreement in quartile distribution, the weighted kappa coefficient (κ w) was used. SETTING: Krakow, Poland. SUBJECTS: One hundred and forty-three 3-year-old children and their mothers, participants of a prospective cohort study. RESULTS: Overall, the SFFQ overestimated energy and nutrient intakes compared with the repeated 24hDR. The median correlation coefficient for energy and nutrient intakes was 0·456, with higher results for Ca, P and riboflavin. Although the κ w value showed only slight to fair agreement between the two methods, about 75 % of the children were classified into the same or adjacent quartile and the level of agreement assessed by the Bland-Altman method for most of the nutrients investigated was good. CONCLUSIONS: The study indicated that the SFFQ might be a useful tool to assess dietary intakes of nutrients by small children, especially for ranking them according their nutrient intake.