The identification of food patterns: a comparison of principal component and principal axis factoring techniques.

INTRODUCTION Dietary patterns are based on the concept that food consumed together or by itself is as important as food or nutrient intake. OBJECTIVES To identify dietary patterns in a sample of nursing professionals and to explore the differences between the patterns found using two techniques: principal components (PC) and principal factorial axis (PAF). METHOD The current report was based on data from 309 participants on a nursing team at a public hospital in Rio de Janeiro. A 24-hour dietary recall was used, resulting in 24 food groups. To identify the dietary patterns, we applied a multivariate analysis, specifically the PC and the PAF, followed by a Varimax orthogonal rotation. RESULTS The Cattell graphic test indicated three factors to be extracted. The communality varied between 0.41 and 0.76. Higher loads than 0.30 were considered in the pattern composition. The two methods identified similar dietary patterns, called traditional patterns. The other two patterns were nominated as healthy and snacks, having inverted position of factors in the applied techniques. CONCLUSION The observed differences refer to: the number of food groups that enter the composition of components and factors; the size of the smaller loads in the PAF and the order of the alimentary patterns, especially those derived from loads of a smaller magnitude. However, these differences do not seem to impact the interpretability of dietary patterns in this population.