Fruit and vegetable food frequencies by fourth and fifth grade students: validity and reliability

Due to the increased emphasis on fruit and vegetable (F+V) consumption and a desire to use the simplest dietary assessment method appropriate to determine F+V intake, we assessed the reliability and validity of weekly and monthly fruit and vegetable food frequency questionnaires (F+V FFQ) among fourth and fifth grade students by comparing them to food records previously validated through school lunch observations.

The multiethnic sample (primarily African-American and Caucasian) included predominantly lower-middle socioeconomic students from 10 classes at one elementary school. F+V FFQ were printed on optical scanning forms and classroom administered on two occasions. Students completed preprinted food record forms at school and received new forms weekly. To allow comparison between the F+V FFQ and food records, a dietitian abstracted information from the records according to a written protocol and transferred it to F+V FFQ forms covering respective time periods. F+V FFQ were converted to estimated daily servings and aggregated to create five F+V indices plus three summary indices. Statistical analyses included Spearman correlations and paired t-tests.

Students demonstrated acceptable reliability in completing food records as well as weekly and monthly F+V FFQ; however, validity was unacceptable for both F+V FFQ versions due to significant overreporting.

Of the two methods studied, the food record procedure is preferred over the FFQ procedure for collecting self-reported F+V consumption data among fourth and fifth grade students.