Validity and reproducibility of a semi-quantitative food frequency questionnaire for use among Portuguese pregnant women

Authors

  • Elisabete Pinto,

    Corresponding author
    1. Department of Hygiene and Epidemiology, University of Porto Medical School, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal,
    Search for more papers by this author
  • Milton Severo,

    1. Department of Hygiene and Epidemiology, University of Porto Medical School, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal,
    2. Institute of Public Health, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal, and
    Search for more papers by this author
  • Sofia Correia,

    1. Department of Hygiene and Epidemiology, University of Porto Medical School, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal,
    2. Institute of Public Health, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal, and
    Search for more papers by this author
  • Isabel Dos Santos Silva,

    1. Department of Hygiene and Epidemiology, University of Porto Medical School, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal,
    2. Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
    Search for more papers by this author
  • Carla Lopes,

    1. Department of Hygiene and Epidemiology, University of Porto Medical School, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal,
    2. Institute of Public Health, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal, and
    Search for more papers by this author
  • Henrique Barros

    1. Department of Hygiene and Epidemiology, University of Porto Medical School, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal,
    2. Institute of Public Health, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal, and
    Search for more papers by this author

Elisabete Pinto, Department of Hygiene and Epidemiology, University of Porto Medical School, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal. E-mail: ecbpinto@med.up.pt

Abstract

This study aimed to evaluate the validity and reproducibility of a semi-quantitative food frequency questionnaire (FFQ) to estimate nutrient intake among Portuguese pregnant women. A sample of 101 pregnant women completed a 3-day food diary (FD) in each pregnancy trimester (reference method) and an interviewer-administered FFQ in the immediate post-partum period. Ranking women according to their usual intake showed that, on average, 65% were classified into the same ±1 quintile and 2.4% into opposite quintiles by the two methods. Energy-adjusted and de-attenuated correlation coefficients ranged from 0.20 (protein) to 0.58 (riboflavin). Similar results were obtained when the FFQ was compared to each trimester-specific FD. To assess the FFQ reproducibility, 70 women in their third pregnancy trimester were interviewed twice within a 2-week interval. The level of agreement was high, with ≥75% of the participants being classified into the same ±1 quintile by the two administrations for 13 of the 15 nutrients examined. A review of the published literature revealed that this is the first FFQ to take the whole pregnancy as its reference time window. Our findings showed that a single administration of this FFQ in the immediate post-partum period is a valid tool to rank Portuguese pregnant women according to their intakes.

Ancillary