Relative validity and reproducibility of WHO indicators for assessment of feeding practices in children under two years of age.

The study aimed to evaluate relative validity and reproducibility of seven WHO indicators of dietary practices in children aged 6-23.9 months. Data from probabilistic sample of children who used primary healthcare services in Rio de Janeiro, Brazil were collected using a 24h dietary recall (24HR) and a closed questionnaire (Q1) on feeding in the day before the study. The last one was reapplied (Q2) around 16 days later. Validity was assessed by comparing the prevalence rates estimated by 24HR and Q1 and calculating the positive (PPV) and negative (NPV) predictive values, sensitivity (Se), specificity (Sp), and accuracy index (AI) for the resulting indicators. For reproducibility, estimated prevalence rates based on Q1 and Q2 were compared and the kappa index and prevalence-adjusted bias-adjusted kappa were estimated. Of the seven estimated indicators, the prevalence of two was overestimated (Continued breastfeeding: 50.0% vs 40.0%; Sweet beverage consumption: 65.1% vs 52.7%) and the prevalence of one was underestimated (Zero vegetable or fruit consumption: 6.5% vs 18.1%). For most indicators, Se and PPV were higher than Sp and NPV. The prevalence rates determined with Q1 and Q2 were similar for 6 indicators. More than half showed good, very good or excellent agreement.