title: Validity and reproducibility of a semi-quantitative food frequency questionnaire for use among Portuguese pregnant women.
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 > or = 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.
authors.affiliation: Department of Hygiene and Epidemiology, University of Porto Medical School, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal. ecbpinto@med.up.pt
authors.forename: Elisabete
authors.initials: E
authors.lastname: Pinto
authors.forename: Milton
authors.initials: M
authors.lastname: Severo
authors.forename: Sofia
authors.initials: S
authors.lastname: Correia
authors.forename: Isabel
authors.initials: I
authors.lastname: dos Santos Silva
authors.forename: Carla
authors.initials: C
authors.lastname: Lopes
authors.forename: Henrique
authors.initials: H
authors.lastname: Barros
mesh_terms: D000328:Adult; D015331:Cohort Studies; D015930:Diet Records; D004034:Diet Surveys; D002149:Energy Intake; D005260:Female; D006801:Humans; D039382:Maternal Nutritional Physiological Phenomena / Q000502:physiology*; D015596:Nutrition Assessment; D011174:Portugal; D049590:Postpartum Period; D011247:Pregnancy; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires / Q000592:standards*; D055815:Young Adult