Multivariate estimate of eating patterns: is the whole different from the parts?

To describe the correlations between eating patterns for the years 2007 to 2012, and for each year of the period from 2007 to 2012.

Cross-sectional study with data from the System of Surveillance of Risk and Protection Factors to Chronic Diseases by Telephone Survey with the selection of 167,761 individuals aged 18 to 44 years old. Eating patterns were identified with a Principal Component Analysis. To compare the effects of the extraction and the estimate of eating patterns among different surveys we conducted the following analyzes: in the first, we used the total data set for the years from 2007 to 2012; in the second, the patterns were estimated in each annual set of data for the period from 2007 to 2012. Steps 1 and 2 were performed with no rotation, with Varimax rotation and with Promax rotation. After extracting the patterns, standardized scores with zero mean were generated for each pattern. The association between the patterns generated in the analyzes was estimated by the Pearson correlation coefficient (r).

In the non-rotated analyzes, the components retained in the set presented correlations that were higher than 0.90, with the retained patterns in each year. In the rotated analyzes, only the first component had correlations that were higher than 0.90.

Estimates of eating patterns either segmented - year by year - or in general - all of the years - showed high correlation and consistency between the patterns identified when in the same data pool.