Dietary assessment methods among school-aged children: Validity and reliability

Background Assessing the diets of children presents unique methodological challenges. Validity and reliability studies of recalls, records, food frequency questionnaires (FFQs), diet histories, and observations among children were reviewed. Methods, Forty-seven studies were published in peer-reviewed English journals between January 1970 and April 1999 of children 5-18 years of age with a sample size of at least 30, Results. Most of the 24-h recall validation studies assessed only a portion of the day, not a 24-h period, with higher agreements for meal versus complete day intake. Food records underestimated energy intake when compared to doubly labeled water. Few studies evaluated children's ability to complete records alone or to record an entire day. FFQs overestimated energy intake; however, validation standards may have over- or underestimated intake or used different referent periods. Reliability studies were identified for FFQs and diet history; results showed higher energy intake in first compared to subsequent administrations. Limited data were available on age, ethnicity, and gender effects. Conclusions. Correlations between the validation standard and dietary method were generally higher for recalls and records than FFQs, It was difficult to generalize the validity and reliability results of dietary assessment methods because of discrepancies in study design, referent periods, and validation standards. (C) 2000 American Health Foundation and Academic Press.