Food frequency questionnaire for children in rural coastal zones of ecuador: Development, relative validity and calibration

Abstract

Food frequency questionnaires are research tools widely used at the population level to assess food intake, especially in childhood. The objectives of this study were to develop and determine the relative validity of the Food Frequency Questionnaire (FFQ) for the evaluation of food intake among Ecuadorian schoolchildren. One hundred children from rural coastal areas of Ecuador, aged 6 to 8 years, were included. Mothers completed 1 FFQ frequency and two 24-hour recalls (R24h gold standard). Pearson correlation, weighted Kappa and the Bland Altman method were used to assess validity. Linear regression models were used including R24h as a dependent variable and FFQ as an independent variable to derive calibration factors. The Pearson coefficients ranged between-0.03 and 0.24. The Kappa values varied between-0.05 and 0.24, the Bland-Altman plots were between the limits near the midline and the calibration factors ranged from-0.01 to 0.16. The FFQ was considered appropriate to evaluate energy and nutrient consumption, however, due to its weak to moderate agreement this must be corrected using calibration values. This FFQ is a useful tool for evaluating diet and the relationship between diet and disease in this population group.