A novel food frequency questionnaire for Brazilian adults based on the Nova classification system: development, reproducibility and validation

Abstract

AbstractThe Nova system categorizes foods according to processing levels, and dietary intake instruments not developed to assess this criteria may introduce bias in epidemiological studies. To address this gap, we developed and validated the Nova Food Frequency Questionnaire (NovaFFQ) for Brazilian adults. The NovaFFQ includes commonly consumed foods and drinks based on 2017-2018 National Food Survey data. Reproducibility was assessed by comparing NovaFFQ estimates on two occasions. Criterion validity was assessed by comparing the mean dietary contribution of Nova groups obtained from the first NovaFFQ against two Nova24h. Strong reproducibility was observed with an intraclass correlation coefficient (ICC) of 0.91 for all Nova groups. Criterion validity showed a moderate ICC, ranging from 0.61 to 0.65, and substantial agreement in ranking individuals, as indicated by prevalence and bias-adjusted kappa, ranging from 0.70 to 0.74. The NovaFFQ is a valid instrument for assessing food consumption according to food processing.