Relative Validity of Three Food Frequency Questionnaires for Assessing Dietary Intakes of Guatemalan Schoolchildren

Objective To determine the relative validity of three food frequency questionnaires (FFQs) compared with results from 24-hour dietary recalls for measuring dietary intakes in Guatemalan schoolchildren. Design A cross-sectional study of primary caregivers (mothers or grandmothers) of 6-11 year-old children. Caregivers completed one of three constructed FFQs to measure the child's dietary consumption in the last week: FFQ1 did not incorporate portion sizes; FFQ2 provided portion sizes; and FFQ3 incorporated pictures of median portion sizes. During the same week, each caregiver also completed three 24-hour dietary recalls. Results from the FFQ were compared with corresponding results from the 24-hour dietary recalls. Setting Santa Catarina Pinula, peri-urban Guatemala City. Subjects Caregivers (n = 145) of 6-11 year-old children: 46 completed FFQ1, 49 completed FFQ2, and 50 completed FFQ3. Results The mean values for all nutrients obtained from the 24-hour dietary recall were lower than for those obtained from the FFQs, excluding folic acid in FFQ3, cholesterol and zinc in FFQ2, and cholesterol, folic acid, magnesium, potassium, sodium, and zinc in FFQ1. Energy-adjusted Pearson correlation coefficients ranged from 0.07 (protein) to 0.54 (cholesterol) for FFQ1 and from 0.05 to 0.74 for FFQ2 and FFQ3. Agreement by both methods (FFQ and 24-hour dietary recalls) of classifying children into the same or adjacent quartiles of energy-adjusted nutrient consumption ranged from 62.0% for cholesterol to 95.9% for vitamin B12 across all three FFQs. Conclusions Our FFQs had moderate to good relative validity in measuring energy and nutrient intakes for 6-11 year-old Guatemalan children. More evidence is needed to evaluate their reproducibility and applicability in similar populations.