The development of a reliable and feasible measure of school children's fruit and vegetable consumption


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Title: The development of a reliable and feasible measure of school children's fruit and vegetable consumption
Contacts: Jennifer Taylor, Bethany Yon and Rachel Johnson at the University of Vermont Department of Nutrition and Food Sciences.

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The development of a reliable and feasible measure of school children's fruit and vegetable consumption

  1. 1. The development of a reliable and feasible measure of school childrens fruit and vegetable consumption Jennifer C Taylor, BS, Bethany A Yon, PhD and Rachel K Johnson, PhD, MPH, RD Nutrition and Food Sciences Dept., University of Vermont, Burlington, VT ABSTRACT METHODS PRELIMINARY RESULTSMost children fail to meet recommended intakes for fruits and vegetables •  A research team of undergraduate nutrition students (n=19) completed Inter-observer Reliability(F/V). Farm to School programs have been proposed as a strategy to 12 hours of training on three methods for measuring children’s F/Vincrease consumption of these foods, but methodology is needed that can consumption during school lunch: weighed plate waste (WPW), direct Raters Intraclass correlations Percent agreement Traysa Reliability coefficient F/V itemsb IORaccurately measure intake. F/V consumption can be accurately measured observation (DO), and digital imaging (DI). (confidence interval) (comparisons)c scoredduring school lunch using weighed plate waste (WPW), but this method is •  The feasibility of each method and inter-observer reliability of DO and DI Direct observationrarely adopted because it is time and labor intensive. Direct observation were tested in the laboratory and school cafeteria. Training 19 10 0.99 (0.98, 1.00) 51 (2493) 94%(DO) and digital imaging (DI) are more feasible, but these methods have •  Data were collected from school lunch trays (n=521) of third-, fourth-, Visit 1 Visit 2 4 5 30 35 0.93 (0.86, 0.97) 0.73 (0.55, 0.85) 57 (103) 61 (65) 96% 89%not been validated against WPW in present-day cafeterias. This study and fifth-graders in two Vermont school cafeterias. Each lunch tray was Visit 3 3 25 0.98 (0.95, 0.99) 45 (45) 98%tested the reliability and feasibility of DO and DI for measuring F/V assigned a colored, numbered sticker, with one color observed during Visit 4 2 21 0.95 (0.88, 0.98) 48 (48) 100%consumption against the gold standard of WPW in two Vermont school each visit. Digital imagingcafeterias. 521 lunch trays were collected over ten school visits; 339 of •  F/V consumption was determined as the difference between mean Visit 1 2 31 0.98 (0.96, 0.99) 55 (55) 98% baseline weights of the foods selected and plate waste for each lunch Visit 2 2 24 0.97 (0.93, 0.99) 44 (44) 96%the lunch trays were observed using WPW, 218 using DO, and 278 using Visit 3 2 30 0.98 (0.96, 0.99) 69 (69) 100%DI. Inter-observer reliability (IOR) was high for both DO and DI; percent tray. For WPW, plate waste was weighed to the nearest gram. For DO Visit 4 2 47 0.99 (0.98, 0.99) 47 (47) 98%agreement scores for IOR were ≥89% and intraclass correlations were and DI, a six-point scale was used to estimate the percent consumed of Visit 5 3 44 0.99 (0.98, 0.99) 73 (219) 98%≥0.70. DO and DI are feasible and reliable methods for measuring F/V each F/V item selected. Visit 6 3 55 0.97 (0.95, 0.98) 113 (339) 92% •  aObserver estimations for total F/V consumption per lunch trayconsumption during school lunch. Further data analyses will test the The University for Vermont Institutional Review Board approved the bObserver estimations for individual F/V items cIn many instances, the same F/V item was estimated by more than two observers, allowing for multiple comparisonsvalidity of DO and DI against WPW. study. dPercentage of estimations within one-quarter serving of another observer’s estimation Analyses BACKGROUND Tests of inter-observer reliability (IOR): •  Percent agreement assessed the consistency of researchers’ plateDespite the well-known benefits of consuming fruits and vegetables (F/V),1 waste estimations for individual F/V items using DO or DI. Observersonly about 20% of children report consuming the recommended five or more were in agreement if estimations were within one-quarter serving ofservings of F/V per day.2,3 Schools are frequently targeted as a place to each other. A score of at least 85% agreement was expected duringimprove children’s dietary habits, and multi-component school interventions each school visit.such as Farm to School aim to increase children’s F/V consumption. •  Intraclass correlations tested reliability of researchers’ estimations forHowever, methodology is needed that can accurately assess children’s F/V F/V consumption per lunch tray using DO or DI.consumption in school. Analyses were conducted using SAS System for Windows (version 9.3, CONCLUSIONSChildren’s self-reports using instruments such as surveys, questionnaires, 2010), and Microsoft Excel (Redmond, WA, 2007)and dietary recalls are subject to error since children may misidentify or Data on F/V consumption were successfully collected using three assessmentforget to report foods (omissions), identify uneaten foods (intrusions), and methods, and DO and DI were reliable for measuring F/V consumption. Uniquehave a difficult time estimating portion sizes.4 Overweight and obese children Data collected during the ten school visits challenges in each cafeteria affected the final number of lunch trays collected.and their parents may be especially prone to misreporting energy and F/V Challenges included students’ selection of second servings of soup, F/V itemsintake.5,6 Distributed missing at the end of the meal without evidence of consumption (e.g. apple cores), 662 lunch trays distributed and students’ and lunch aides’ disposal of trays prior to final imaging, estimations, or 1104 maximum possible observationsAccurate measurement of children’s food intake can be obtained using the Incomplete Data weighing. Additional analyses will be conducted to test the validity of DO and DI“gold standard” of weighed plate waste, but this method is time and labor 141 lunch trays removed estimations against the gold standard of WPW. DI may be especially promising since (21.3% of distributed)intensive.7 Two other methods – direct observation and digital imaging – 269 tray observations removed it requires the least time and labor to collect data on F/V consumption. (24.4% of distributed)have been used to estimate consumption by observation, but validation of Tray Observationsthese methods has generally been limited to studies in environments more 521 lunch trays collectedcontrolled than the busy school cafeteria, such as the laboratory8 or 835 tray observations collected References No F/V Selectedhospital.9 Earlier studies of direct observation validated the method against 85 lunch trays removed 1.  Bazzano LA. The high cost of not consuming fruits and vegetables. J Am Diet Assoc. 2006;106(9):1364-8. 2.  Robinson-O’Brien R, Burgess-Champoux T, Haines J, Hannan P, Neumark-Sztainer D. Associations between school mealsweighed plate waste in a school cafeteria,10 but present-day school (12.8% of distributed) 126 tray observations removed offered through the national school lunch program and the school breakfast program and fruit and vegetable intake amongcafeterias pose unique challenges. (11.4% of distributed) ethnically diverse, low-income children. J Sch Health. 2010;80(10):487-492. 3.  Guenther PM, Dodd KW, Reedy J, Krebs-Smith SM. Most Americans eat much less than recommended amounts of fruits and F/V Tray Observations vegetables. J Am Diet Assoc. 2006;106(9):1371-9. 436 F/V lunch trays collected 4.  Livingstone MBE, Robson PJ, Wallace JMW. Issues in dietary intake assessment of children and adolescents. Br J Nutr. RESEARCH OBJECTIVE 709 F/V tray observations collected 2004;92(Suppl. 2):S213-S222. 5.  Burrows TL, Martin RJ, Collins CE. A systematic review of the validity of dietary assessment methods in children when compared with the method of doubly labeled water. J Am Diet Assoc. 2010;110(10):1501-10. To establish a reliable and feasible method for 6.  Burrows TL, Warren JM, Colyvas K, Garg ML, Collins CE. Validation of overweight children’s fruit and vegetable intake using plasma carotenoids. Obesity (Silver Spring). 2009;17(1):162-8. measuring school children’s consumption of F/V Weighed Plate Waste Direct Observation Digital Imaging 7.  Kirks B, Wolff H. A comparison of methods for plate waste determinations. J Am Diet Assoc. 1985;85(3):328-31. 8.  Williamson DA, Allen HR, Martin PD, et al. Comparison of digital photography to weighed and visual estimation of portion sizes. during school lunch in a variety of school 277 F/V tray observations collected 199 F/V tray observations collected 233 F/V tray observations collected J Am Diet Assoc. 2003;103(9):1139-45. 9.  Connors PL, Rozell SB. Using a visual plate waste study to monitor menu performance. J Am Diet Assoc. 2004;104(1):94-6. cafeteria settings. 10. Comstock EM, St Pierre RG, Mackiernan YD. Measuring individual plate waste in school lunches. Visual estimation and children’s ratings vs. actual weighing of plate waste. J Am Diet Assoc. 1981;79(3):290-296. This study was funded by the USDA - Vermont Agricultural Experiment Station. The authors thank Alan Howard and Leah Conchieri for their support with data and statistical analyses.