Reproducibility and Validity of a Short Food Frequency Questionnaire for Dietary Assessment in Children Aged 7–9 Years in Spain

The purpose of this study was to examine if the short semi-quantitative food frequency questionnaire(FFQ) is a reliable and valid tool to assess the diet of Spanish children aged 7–9 years. We collected data from 156 children of the birth cohort INMA (Infancia y Medio Ambiente (Environment and Childhood)). Children’s parents or care-giverscompleted a 46-item FFQ on two occasions over a 9–12-month period about the children’s diet. To explore the reproducibility of the FFQ, the nutrient and food groupintake collected from the both FFQs were compared, while validity was examined by contrasting the nutrient values from the FFQs and the average of three 24-hour dietary recalls (24hDRs) taken in this period, and also with the concentration of several vitamins in the blood (carotenoids, vitamin D and α-tocopherol). Pearson and de-attenuated correlation coefficientswere calculated. The average correlation coefficientsfor nutrient intake’s reproducibility was 0.41, ranging from 0.25 (calcium) to 0.65 (β- carotene), and for food groupintake was 0.45, ranging from 0.18 (cereals) to 0.68 (sweetened beverages). Correlation coefficientsslightly improved when we compared energy-adjusted intakes. The average correlation coefficientsfor validity against 24hDRs was 0.34 for energy-adjusted intakes, and 0.39 when de-attenuation coefficients were used. The validity coefficients against the blood concentrations of vitamins were 0.38 for β- cryptoxanthin, 0.26 for lycopene, 0,23 for α- caroteneand 0.15 for β- carotene, all of them statistically significant (p < 0.05). This study suggests that our brief FFQ is a suitable tool for the dietary assessment of a wide range of nutrients and food groupsin children 7–9 years, despite the low to moderate reproducibility and validity observed for some nutrients.