Relative Validity of a Semi-Quantitative Food Frequency Questionnaire to Estimate Dietary Intake According to the NOVA Classification in Mexican Children and Adolescents

Abstract

Background: Ultra-processed foods (UPFs) are associated with poor diet quality and chronic diseases. UPFs fall into 1 of the following 4 groups classified according to the extent and purpose of processing: group 1 is unprocessed or minimally processed foods (MPFs); group 2 is processed culinary ingredients; group 3 is processed foods; and group 4 is UPFs.

Objective: The aim of this study was to evaluate the relative validity of a semi-quantitative food frequency questionnaire (SFFQ) compared with two 24-hour dietary recalls (24DRs) `to estimate dietary intake per NOVA food group in Mexican children and adolescents.

Design: This study is a secondary analysis of dietary data from a subsample of children and adolescents who participated in the 2012 Mexican National Health and Nutrition Survey.

Participants/setting: The study participants were 217 children (aged 5 through 11 years) and 165 adolescents (aged 12 through 19 years) with complete information for the SFFQ and two 24DRs.

Main outcome measures: Daily averages of energy intake and percent of energy intake for each NOVA category were calculated using the SFFQ and two 24DRs.

Statistical analysis: To assess relative validity, the SFFQ was compared with two 24DRs to estimate dietary intake per NOVA food group. Mean differences, Spearman correlations, intraclass correlations coefficients (ICCs), and Bland-Altman plots for continuous variables and weighted κ for ordinal variables were calculated.

Results: For percentage of energy intake, ICCs in children and adolescents were moderate for MPFs (ICC = 0.47 and ICC = 0.56, respectively) and UPFs (ICC = 0.53 and ICC = 0.57, respectively). Bland-Altman plots indicated reasonably consistent agreement for UPFs and MPFs groups in children and adolescents. Classification by quintiles was acceptable in all groups.

Conclusions: Data from this study indicated reasonable relative validity of the SFFQ to rank the percentage of energy intake from MPFs and UPFs in Mexican children and adolescents.

Keywords: Children and adolescents; Food frequency questionnaire; Mexico; NOVA; Relative validity.