Validation of a digital photographic method for assessment of dietary quality of school lunch sandwiches brought from home

  • Marianne S. Sabinsky Technical University of Denmark, National Food Institute
  • Ulla Toft Glostrup University Hospital
  • Klaus K. Andersen Danish Cancer Society Research Center
  • Inge Tetens Technical University of Denmark, National Food Institute
Keywords: Food intake, packed lunches, diet assessment, children

Abstract

Background: It is a challenge to assess children’s dietary intake. The digital photographic method (DPM) may be an objective method that can overcome some of these challenges.

Objective: The aim of this study was to evaluate the validity and reliability of a DPM to assess the quality of dietary intake from school lunch sandwiches brought from home among children aged 7-13 years.

Design: School lunch sandwiches (n=191) were prepared to represent randomly selected school lunch sandwiches from a large database. All components were weighed to provide an objective measure of the composition. The lunches were photographed using a standardised DPM. From the digital images, the dietary components were estimated by a trained image analyst using weights or household measures and the dietary quality was assessed using a validated Meal Index of Dietary Quality (Meal IQ). The dietary components and the Meal IQ obtained from the digital images were validated against the objective weighed foods of the school lunch sandwiches. To determine interrater reliability, the digital images were evaluated by a second image analyst.

Results: Correlation coefficients between the DPM and the weighed foods ranged from 0.89 to 0.97. The proportion of meals classified in the same or an adjacent quartile ranged from 98% (starch) to 100% (fruits, vegetables, fish, whole grain, and Meal IQ). There was no statistical difference between fish, fat, starch, whole grains, and Meal IQ using the two methods. Differences were found for fruits and vegetables; BlandAltman analyses showed a tendency to underestimate high amounts of these variables using the DPM. For interrater reliability, kappa statistics ranged from 0.59 to 0.82 across the dietary components and Meal IQ.

Conclusions: The standardised DPM is a valid and reliable method for assessing the dietary quality of school lunch sandwiches brought from home.

Keywords: food intake; packed lunches; diet assessment; children

(Published: 12 July 2013)

Citation: Food & Nutrition Research 2013. 57: 20243 - http://dx.doi.org/10.3402/fnr.v57i0.20243

Downloads

Download data is not yet available.

Author Biographies

Marianne S. Sabinsky, Technical University of Denmark, National Food Institute

Division of Nutrition

PhD-student 

Ulla Toft, Glostrup University Hospital

Research Centre for Prevention and Health

Senior Scientist, PhD, Msc Human Nutrition 

Klaus K. Andersen, Danish Cancer Society Research Center

Statistics, Bioinformatics and Registry

Head of Unit, PhD

Inge Tetens, Technical University of Denmark, National Food Institute

Division of Nutrition

Professor in Nutrition

 

Published
2013-07-12
How to Cite
1.
Sabinsky M, Toft U, Andersen K, Tetens I. Validation of a digital photographic method for assessment of dietary quality of school lunch sandwiches brought from home. Food & Nutrition Research [Internet]. 12Jul.2013 [cited 21Sep.2018];. Available from: https://foodandnutritionresearch.net/index.php/fnr/article/view/524
Section
Original Articles