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

• Autor(a) principal: Cardoso,Marly Augusto
• Data de Publicação: 2010
• Outros Autores: Tomita,Luciana Yuki, Laguna,Elaine Cristina
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Cadernos de Saúde Pública
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0102-311X2010001100007
• topic: Food Consumption; Validation Studies; Questionnaires; Women

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.