Validation and Reproducibility of a Semi-Quantitative FFQ as a Measure of Dietary Intake in Adults From Puerto Rico

Public Health Nutr. 2015 Oct;18(14):2550-8. doi: 10.1017/S1368980014003218. Epub 2015 Jan 27.


Objective: We aimed to assess the relative validity and reproducibility of a semi-quantitative FFQ in Puerto Rican adults.

Design: 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.

Setting: Medical Sciences Campus, University of Puerto Rico.

Subjects: 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.

Keywords: FFQ; Food records; Puerto Rico; Reproducibility; Validation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.
  • Validation Study

MeSH terms

  • Adolescent
  • Adult
  • Diet Records
  • Diet Surveys
  • Diet*
  • Energy Intake
  • Feeding Behavior*
  • Female
  • Humans
  • Male
  • Nutrition Assessment*
  • Puerto Rico
  • Reproducibility of Results
  • Surveys and Questionnaires / standards*
  • Young Adult