Assessing the validity of a food frequency questionnaire among low-income women in São Paulo, southeastern Brazil

Abstract

This study describes the validity of a food frequency questionnaire (FFQ) in 93 low-income women (20-65 years), participating in a case-control study in São Paulo, Brazil. Two FFQ (FFQ1 and FFQ2, 12 months apart) and three 24-hour dietary recalls (24hR) were conducted between 2003 and 2004 to estimate dietary intake during the past year. The Pearson correlation coefficients (crude, energy-adjusted and de-attenuated) were used for comparisons between FFQ and 24hR. The agreement between the methods was further examined by the Bland-Altman analysis. For the assessment of long-term reliability, the energy-adjusted intra-class correlation coefficients were mostly around 0.40, but higher for vitamin A and folate (0.50-0.56). Energy-adjusted, attenuation-corrected Pearson validity correlations between FFQ and DR ranged from 0.30-0.54 for macronutrients to 0.20-0.48 for micronutrients, with higher value for calcium (0.75). There were small proportions of grossly misclassified nutrient intakes, while Bland-Altman plots indicated that the FFQ is accurate in assessing nutrient intake at a group level.

Assessing the validity of a self-administered food-frequency questionnaire (FFQ) in the adult population of Newfoundland and Labrador, Canada

“…In regards to energy, lower concordance coefficients have been reported in the Willett FFQ (0.16 for women and 0.18 for men) and the Block FFQ (0.37 for women and 0.41 for men) [11] as compared with 0.26 (women) and 0.44 (men) derived from our study. It was particularly noticeable that our correlations for protein were unfavourable, especially in men (0.13), however, our findings were similar to those obtained from a Brazilian cohort (0.20) [45]. For carbohydrate in women, our study yielded a coefficient of 0.38, which compares favourably with the Jackson Heart Study (0.32) [46].…”

“…In the present study, the lower correlation values found in some categories may indicate that the FFQ to some extent systemically over-/under- estimated intake of these nutrients, however, error in over/under estimation by the FFQ is expected. Likewise, Dehghan et al (2012) , Wang et al (2008) , and Cardoso et al (2010) found energy adjustment did not improve the crude correlation in their studies [43-45]. …”

“…Although our correlations for vitamin A in women (0.38) and carotene in men (0.28) were low, they were significant with p-value <0.05, suggesting reasonably good agreement between the two instruments. Other studies have also reported poor correlations for micronutrients [6,44,45], including vitamin A and carotene.…”

Reprodutibilidade e validade relativa do Questionário de Frequência Alimentar do ELSA-Brasil

“…No que diz respeito à reprodutibilidade do QFA, foram encontrados valores de CCI (0,55-0,83) similares aos observados em outros estudos 21,22 ; da mesma forma, os valores de concordância encontrados nas análises de validade (0,20-0,72) também se mostraram compatíveis com achados de pesquisas semelhantes 21,22,23,24 . Estudos similares apresentam frequentemente valores de coeficiente de correlação entre 0,4 a 0,7, que são considerados como de razoável reprodutibilidade e validade 11 .…”

Clinical and nutritional status in the late postoperative of pancreaticoduodenectomy: influence of pylorus preservation procedure

“…Influence of pylorus preservation procedure that the food intake was over-reported due to limitations inherent to food questionnaires methodologies 18 .…”