Questionário de frequência alimentar ELSA-Brasil : proposta de redução e validação da versão reduzida

Introdução. O QFA tem sido o instrumento de escolha para a obtenção das informações dietéticas em estudos epidemiológicos, especialmente aqueles relacionados às DCNT. Muitos QFAs têm sido elaborados para a realização de inquéritos epidemiológicos nacionais, buscando a avaliação da dieta habitual da população a ser estudada, mas a maior parte desses estudos apresenta uma lista extensa de alimentos, com tendência a apresentar maior índice de não resposta, elevando o tempo e o custo dos estudos. Objetivo. Desenvolver versão reduzida do QFA ELSA-Brasil e estudar a validade relativa do QFA versão reduzida. Métodos. A partir do QFA ELSA-Brasil com 114 itens alimentares realizou-se a redução da lista por regressão linear múltipla, frequência de consumo e composição nutricional dos alimentos. Foi conduzida análise de sensibilidade e kappa na qual foi avaliada a concordância entre os métodos (QFA orginal e QFA reduzido) por meio da classificação dos indivíduos segundo a distribuição em tercis de consumo de energia e nutrientes. Foram apresentados os somatórios dos percentuais de concordâncias exata e adjacente . Para avaliação da validade os valores de energia e nutrientes dos RA foram deatenuados e as variáveis de ambos os métodos (QFA e RA) foram log transformados, foi aplicado correlação de Pearson, correlação intraclasse, além da sensibilidade e kappa para avaliar concordância. Para avaliar diferenças e vieses de energia e nutrientes obtidos entre os métodos (QFA reduzido registros alimentares), foram construídos gráficos com as diferenças absolutas entre os valores no eixo das ordenadas e a média de ingestão calculada por meio dos três registros alimentares nas abscissas. Resultados. Foi obtida redução aproximada de 33% da lista de alimentos original. Assim, a nova lista contém 76 itens alimentares. Com relação a validação os coeficientes de correlação intraclasse variaram de 0,17 (selênio) a 0,66 (cálcio). Foi encontrado valores de somatório da distribuição exata mais adjacente acima de 60% de concordância entre os métodos QFA e RA. Conclusão. Tendo em vista os resultados deste estudo, conclui-se que seus objetivos foram alcançados. O QFA ELSA-Brasil foi reduzido de 114 itens alimentares para 76, redução aproximada de 33%, e ainda assim foi possível manter a capacidade de medir relativamente bem energia e os nutrientes selecionados, obtendo ótima concordância e correlação com o QFA originalIntroduction. The FFQ has been the instrument of choice for obtaining dietary information in epidemiological studies, especially those related to NCDs. Many QFAs have been prepared for the national epidemiological surveys, seeking review of the habitual diet of the population being studied, but most of these studies has an extensive list of foods that tend to have higher rate of non-responde, raising the time and cost studies. Objective. Develop reduced version of the FFQ ELSA-Brasil and study the relative validity of the FFQ reduced version. Methods. From the FFQ ELSA-Brasil with 114 food items was held to reduce the list by multiple linear regression, frequency of consumption and nutrient composition of foods. We conducted sensitivity analysis and kappa in which we evaluated the concordance between the methods (FFQ original and FFQ reduced) by classifying individuals into tertiles according to the distribuition of energy and nutrients. Were presented the sums of percentages of concordance exact and adjacent . To assess the validity of the values of energy and nutrients were deattenuated food records and variables of both methods (FFQ and food records) were log transformed, we applied Pearson correlation, intraclass correlation, and sensitivity and kappa to assess agreement. To evaluate differences and biases of energy and nutrients obtained between methods (FFQ - food records) were constructed graphs with absolute differences between the values in the y-axis and the average estimated intake by three food records in the abscissas. Results. Was obtained by reduction of approximately 33% of the original food list. Thus, the new list contains 76 food items. With respect to the validation intraclass correlation coefficients ranged from 0.17 (selenium) to 0.66 (calcium). Found the sum of the values of most adjacent exact distribution above 60% agreement between the methods and food records. Conclusion. Given the results of this study, it is concluded that its objectives were achieved. The FFQ ELSA-Brasil was reduced from 114 to 76 food items, reduction of approximately 33%, and it was still possible to maintain the ability to measure relatively good energy and selected nutrients, obtaining excellent agreement and correlation with the original FF

Comparison of a short version of the Food Frequency Questionnaire with its long version - a cross-sectional analysis in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

ABSTRACT CONTEXT AND OBJECTIVE: The food frequency questionnaire (FFQ) is the preferred instrument for obtaining dietary information in epidemiological studies. A short form of the FFQ was compared with the original version that was used in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), and also with three 24-hour dietary recalls. DESIGN AND SETTING: Cross-sectional study carried out in six Brazilian state capitals. METHODS: Multiple linear regression was used to reduce the original food and drink list of the FFQ, which had contained 114 food items. The frequency of consumption and nutritional composition of the foods were also taken into consideration. To assess the validity of the shortened FFQ, the energy and nutrients values of the 24-hour dietary recalls were deattenuated and log-transformed. RESULTS: The list of the FFQ of ELSA-Brasil was reduced to 76 food items. The intraclass correlation coefficients in the validation study ranged from 0.17 (selenium) to 0.66 (calcium). CONCLUSIONS: The number of items was reduced by 33%, while still maintaining relatively good capacity to measure energy and selected nutrients