Reporting accuracy of packed lunch consumption among Danish 11-year-olds differ by gender

Abstract

Background: Packed lunch is the dominant lunch format in many countriesincluding Denmark. School lunch is consumed unsupervised, andself-reported recalls are appropriate in the school setting. However,little is known about the accuracy of recalls in relation to packedlunch.Objective: To assess the qualitative recall accuracy of self-reportedconsumption of packed lunch among Danish 11-year-old children inrelation to gender and dietary assessment method.Design: A cross-sectional dietary recall study of packed lunchconsumption. Digital images (DIs) served as an objective referencemethod to determine food items consumed. Recalls were collected with alunch recall questionnaire (LRQ) comprising an open-ended recall (OE-Q)and a pre-coded food group prompted recall (PC-Q). Individual interviews(INTs) were conducted successively. The number of food items wasidentified and accuracy was calculated as match rates (% identified byDIs and reported correctly) and intrusion rates (% not identified byDIs but reported) were determined.Setting and subjects: Three Danish public schools from Copenhagen. Atotal of 114 Danish 11-year-old children, mean (SE) age = 11.1 (0.03),and body mass index = 18.2 (0.26).Results: The reference (DIs) showed that girls consumed a higher numberof food items than boys {[}mean (SE) 5.4 (0.25) vs. 4.6 (0.29) items (p= 0.05)]. The number of food items recalled differed between genderswith OE-Q recalls (p = 0.005) only. Girls' interview recalls were moreaccurate than boys' with higher match rates (p = 0.04) and lowerintrusion rates (p = 0.05). Match rates ranged from 67-90% andintrusion rates ranged from 13-39% with little differences betweengirls and boys using the OE-Q and PC-Q methods.Conclusion: Dietary recall validation studies should not only considermatch rates as an account of accuracy. Intrusions contribute toover-reporting in non-validation studies, and future studies shouldaddress recall accuracy and inaccuracies in relation to gender andrecall method.