Comparison of a self-administered quantitative food amount frequency questionnaire with 4-day estimated food records

Our objective was to assess the relative validity of a self-administered fo od amount frequency questionnaire (FAQ), using if-day estimated food record s (FRs) as a reference method, for use in a subsequent clinical study of pa tients undergoing heart surgery. Thirty healthy subjects (19 males, 11 fema les), aged 45-75 years, were randomly recruited from patient lists generate d by two local GP practices in Oxford. Complete data from the FAQ and FR, a dministered twice 6 months apart, were available for 25 subjects (16 males, 9 females). For absolute nutrient values, intakes of protein, CHO, total f at, PUFA, thiamin, iron, dietary fibre and alcohol were not significantly d ifferent between the FAQ and FR, and Pearson's correlation coefficients ran ged from 0.28 for protein to 0.88 for total fat. Estimates from the FAQ wer e within +/- 10% of the estimates produced by the FR for two-thirds of nutr ients. When nutrients were expressed as a percentage of total energy intake , no statistically significant differences were observed for any nutrient b etween the two methods, and correlations ranged from 0.32 for protein to 0. 80 for SFA. In conclusion, the broad dietary patterns obtained by the two m ethods of assessment were comparable. This simple and inexpensive FAQ can b e used to usefully estimate group intakes for a variety of nutrients in the study of patients undergoing heart surgery.