title: Validation and reproducibility of a semi-quantitative FFQ as a measure of dietary intake in adults from Puerto Rico.
abstract: OBJECTIVE
  We aimed to assess the relative validity and reproducibility of a semi-quantitative FFQ in Puerto Rican adults.
  
  
  METHODS
  Participants completed an FFQ, followed by a 6 d food record and a second administration of the FFQ, 30 d later. All nutrients were log transformed and adjusted for energy intake. Statistical analyses included correlations, paired t tests, cross-classification and Bland-Altman plots.
  
  
  METHODS
  Medical Sciences Campus, University of Puerto Rico.
  
  
  METHODS
  Convenience sample of students, employees and faculty members (n 100, ≥21 years). Data were collected in 2010.
  
  
  RESULTS
  A total of ninety-two participants completed the study. Most were young overweight females. All nutrients were significantly correlated between the two FFQ, with an average correlation of 0·61 (range 0·43-0·73) and an average difference of 4·8 % between them. Most energy-adjusted nutrients showed significant correlations between the FFQ and food record, which improved with de-attenuation and averaged 0·38 (range 0·11-0·63). The lowest non-significant correlations (≤0·20) were for trans-fat, n 3 fatty acids, thiamin and vitamin E. Intakes assessed by the FFQ were higher than those from the food record by a mean of 19 % (range 4-44 %). Bland-Altman plots showed that there was a systematic trend towards higher estimates with the FFQ, particularly for energy, carbohydrate and Ca. Most participants were correctly classified into the same or adjacent quintile (average 66 %) by both methods with only 3 % gross misclassification.
  
  
  CONCLUSIONS
  This semi-quantitative FFQ is a tool that offers relatively valid and reproducible estimates of energy and certain nutrients in this group of mostly female Puerto Ricans.
authors.affiliation: 1Nutrition Program,Graduate School of Public Health,Medical Sciences Campus,University of Puerto Rico,San Juan,PR 00935.
authors.forename: Cristina
authors.initials: C
authors.lastname: Palacios
authors.affiliation: 2Center for Clinical Research and Health Promotion,School of Dental Medicine,Medical Sciences Campus,University of Puerto Rico,San Juan,Puerto Rico.
authors.forename: Maria Angelica
authors.initials: MA
authors.lastname: Trak
authors.affiliation: 1Nutrition Program,Graduate School of Public Health,Medical Sciences Campus,University of Puerto Rico,San Juan,PR 00935.
authors.forename: Jesmari
authors.initials: J
authors.lastname: Betancourt
authors.affiliation: 2Center for Clinical Research and Health Promotion,School of Dental Medicine,Medical Sciences Campus,University of Puerto Rico,San Juan,Puerto Rico.
authors.forename: Kaumudi
authors.initials: K
authors.lastname: Joshipura
authors.affiliation: 3Department of Clinical Laboratory & Nutritional Sciences,University of Massachusetts at Lowell,Boston,MA,USA.
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Tucker
mesh_terms: D000293:Adolescent; D000328:Adult; D004032:Diet; D015930:Diet Records; D004034:Diet Surveys; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D015596:Nutrition Assessment; D011647:Puerto Rico; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*; D055815:Young Adult
keywords: FFQ; Food records; Puerto Rico; Reproducibility; Validation