Reliability and validity of an FFQ for South American children and adolescents from the SAYCARE study.

Objective:The purpose of this study was to analyse the reliability and validity of a semi-quantitative FFQ to assess food group consumption in South American children and adolescents.Design:The SAYCARE (South American Youth/Child cARdiovascular and Environmental) study is an observational, multicentre, feasibility study performed in a sample of 3- to 18-year-old children and adolescents attending private and public schools from six South American countries. Participants answered the FFQ twice with a two-week interval and three 24-h dietary recalls. Intraclass and Spearman's correlations, weighted Cohen's kappa (kappa w), percentage of agreement and energy-adjusted Pearson's correlation coefficients were calculated.Setting:Seven cities in South America (Buenos Aires, Lima, Medelin, Montevideo, Santiago, Sao Paulo and Teresina).Subjects:A sample of 200 children and 244 adolescents for reliability analyses and 252 children and 244 adolescents for validity analyses were included.Results:Depending on the food group, for children and adolescents, reliability analyses resulted in Spearman's coefficients from 0.47 to 0.73, intraclass correlation coefficients from 0.66 to 0.99, kappa w coefficients from 0.35 to 0.63, and percentage of agreement between 72.75 and 83.52 %. In the same way, validity analyses resulted in Spearman's coefficients from 0.17 to 0.37, energy-adjusted Pearson's coefficients from 0.17 to 0.61, kappa w coefficients from 0.09 to 0.24, and percentages of agreement between 45.79 and 67.06 %.Conclusion:The SAYCARE FFQ achieved reasonable reliability and slight-moderate validity for almost all food groups intakes. Accordingly, it can be used for the purpose of ranking the intake of individuals within a population.