title: Validity of a food frequency questionnaire in assessing nutrient intakes of low-income pregnant women.
abstract: OBJECTIVE
  In 1989, a validation study of eight nutrients was performed on a modified food frequency questionnaire (FFQ) specifically designed for low-income pregnant women. The purpose of this study was to broaden the scope of the previous study by assessing the validity of the FFQ for 17 additional nutrients.
  
  
  METHODS
  The Pregnancy Food Frequency Questionnaire (PFFQ) was administered to a sample of 295 low-income, pregnant women aged 14-43 years living in Massachusetts. A randomly selected subsample of 101 women who provided at least one diet recall and reported intake of less than 4,500 calories were included in this analysis.
  
  
  RESULTS
  Mean intake of 25 nutrients as assessed by one administration of the PFFQ and up to three diet recalls collected over 1 month were similar. Unadjusted correlation coefficients between nutrient intake measured by diet recalls and the questionnaire ranged from .28 (carotene) to .61 (folate). After adjusting for energy intake the correlations ranged from .03 (B12) to .46 (folate). The correlations corrected for day-to-day variation were higher, ranging from .07 (B12) to .90 (zinc). The mean correlation was .47 and there were 54% over .40.
  
  
  CONCLUSIONS
  A food frequency questionnaire for English-speaking, low-income, pregnant women can provide maternal and child health practitioners and researchers a valid estimate of diet across a wide range of nutrients.
authors.affiliation: Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA. ewei@hsph.harvard.edu
authors.forename: E K
authors.initials: EK
authors.lastname: Wei
authors.forename: J
authors.initials: J
authors.lastname: Gardner
authors.forename: A E
authors.initials: AE
authors.lastname: Field
authors.forename: B A
authors.initials: BA
authors.lastname: Rosner
authors.forename: G A
authors.initials: GA
authors.lastname: Colditz
authors.forename: C W
authors.initials: CW
authors.lastname: Suitor
mesh_terms: D000293:Adolescent; D000328:Adult; D004034:Diet Surveys; D004522:Educational Status; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D017533:Marital Status; D008404:Massachusetts; D008423:Maternal Age; D011203:Poverty / Q000706:statistics & numerical data; D011247:Pregnancy / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*