Shortening the retention interval of 24-hour dietary recalls increases fourth-grade children's accuracy for reporting energy and macronutrient intake at school meals.

Background: Accurate information about children's intake is crucial for national nutrition policy and for research and clinical activities. To analyze accuracy for reporting energy and nutrients, most validation studies utilize the "conventional approach," which was not designed to capture errors of reported foods and amounts. The "reporting-error-sensitive approach" captures errors of reported foods and amounts.

Objective: To extend results to energy and macronutrients for a validation study concerning retention interval (elapsed time between to-be-reported meals and the interview) and accuracy for reporting school-meal intake, the conventional and reporting-error-sensitive approaches were compared. DESIGN AND PARTICIPANTS/SETTING: Fourth-grade children (n=374) were observed eating two school meals, and interviewed to obtain a 24-hour recall using one of six interview conditions from crossing two target periods (prior 24 hours and previous day) with three interview times (morning, afternoon, and evening). Data were collected in one district during three school years (2004-2005, 2005-2006, and 2006-2007).

Main Outcome Measures: Report rates (reported/observed), correspondence rates (correctly reported/observed), and inflation ratios (intruded/observed) were calculated for energy and macronutrients.

Statistical Analyses Performed: For each outcome measure, mixed-model analysis of variance was conducted with target period, interview time, their interaction, and sex in the model; results were adjusted for school year and interviewer.

Results: With the conventional approach, report rates for energy and macronutrients did not differ by target period, interview time, their interaction, or sex. With the reporting-error-sensitive approach, correspondence rates for energy and macronutrients differed by target period (four P values <0.0001) and the target period by interview-time interaction (four P values <0.0001); inflation ratios for energy and macronutrients differed by target period (four P values <0.0001), and inflation ratios for energy and carbohydrate differed by the target period by interview-time interaction (both P values <0.005).

Conclusions: Shortening the retention interval of dietary recalls increases accuracy for reporting energy and macronutrients. For validation studies, it is best to obtain reference information from a method that provides details about foods and amounts consumed and to use an analytic approach that captures errors of reported foods and amounts.