title: 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: 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.
  
  
  METHODS
  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.
authors.affiliation: Department of Public Health, Universidade Federal do Espírito Santo, Espírito Santo, Brazil.
authors.forename: Livia Welter
authors.initials: LW
authors.lastname: Mannato
authors.affiliation: Universidade Federal do Espírito Santo, Vitória, Espírito Santo, Brazil.
authors.forename: Taisa Sabrina Silva
authors.initials: TS
authors.lastname: Pereira
authors.affiliation: Department of Maternal and Child Nursing and Public Health, School of Nursing, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Velasquez-Melendez
authors.affiliation: Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
authors.forename: Letícia de Oliveira
authors.initials: Lde O
authors.lastname: Cardoso
authors.affiliation: Department of Internal Medicine, School of Medicine, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Isabela Martins
authors.initials: IM
authors.lastname: Benseñor
authors.affiliation: Department of Integrated Health Education, Universidade Federal do Espírito Santo, Vitória, Espírito Santo, Brazil.
authors.forename: Maria del Carmen Bisi
authors.initials: Mdel C
authors.lastname: Molina
mesh_terms: D000328:Adult; D000368:Aged; D001938:Brazil; D004032:Diet / Q000706:statistics & numerical data*; D015930:Diet Records; D004034:Diet Surveys / Q000379:methods* / Q000592:standards*; D004812:Epidemiologic Methods; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D015203:Reproducibility of Results; D013997:Time Factors