Relative validity of a semi-quantitative FFQ in 3-year-old Polish children.

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.