Reproducibility and relative validity of a semiquantitative food frequency questionnaire in European preschoolers: The ToyBox study.

Objectives: The aim of this study was to examine the reproducibility and relative validity of a semiquantitative food frequency questionnaire (FFQ) in assessing food group estimates.

Methods: Food group estimates were assessed via a 37-item FFQ and a 3-d food record (FR). Pearson's correlation coefficients for log-transformed values were calculated to assess the reproducibility and Spearman's rank correlation coefficients for log-transformed values were calculated to assess the validity.

Socioeconomic factors are associated with folate and vitamin B12 intakes and related biomarkers concentrations in European adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence study.

Because socioeconomic factors (SEFs) may influence dietary quality and vitamin intakes, this study aimed to examine associations between socioeconomic factors and folate and vitamin B12 intakes as well as their related biomarkers in the Healthy Lifestyle in Europe by Nutrition in Adolescence study. Vitamin intakes were obtained from two 24-hour recalls in 2253 participants (47% males). Vitamin B biomarkers were assessed in a subsample of 977 participants (46% males).