Reliability and validity of the FFQ and feeding index for 7-to 24-month-old children after congenital heart disease surgery

BACKGROUND: Congenital heart disease (CHD) is the most common congenital defect in neonates. Infants with CHD often have more nutritional difficulties, but currently, there is no unified Food Frequency Questionnaire (FFQ) for infants and young children aged 7–24 months in China. Therefore, we designed this study to assess the reliability and validity of the FFQ and feeding index for 7-to 24-month-old children after congenital heart disease surgery. METHODS: From July to October 2018, infants and young children aged 7–24 months after congenital heart disease surgery in Guangzhou were selected. Participants were categorized into two groups, in the first group (n = 95), the FFQ was completed twice at intervals of 7–10 days to assess reproducibility. In the second group (n = 98), participants accomplished both the FFQ and the 24-h diet records from 3 consecutive days to assess validity. The score of the Infant and Child Feeding Index (ICFI) and its qualified rate were caculated. Intraclass correlation coefficients (ICC) and Spearman correlation coefficient (SCC) were calculated for reliability and validity, respectively. RESULTS: The average intraclass correlation coefficients and spearman correlation coefficient of the FFQ were 0.536 and 0.318, all with statistical significance except the frequency of meat added. The ICFI of the first group was 8.61 (± 3.20), the qualified rate was 0.06% (6/95). The intraclass correlation coefficients of the ICFI ranged from 0.374 to 0.958; and the spearman correlation of the ICFI was -0.066 to -0.834. CONCLUSIONS: The FFQ possesses satisfactory reliability and moderate validity. The reliability of the ICFI is acceptable, but the validity results are quite different, indicating that the questionnaire is limited in the evaluation of the ICFI. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12887-022-03357-4.