The Anti Cancer Council of Victoria FFQ: relative validity of nutrient intakes compared with weighed food records in young to middle-aged women in a study of iron supplementation

Abstract

To assess the validity of the Anti Cancer Council of Victoria food frequency questionnaire (ACCVFFQ) relative to seven-day weighed food records (WFRs) in 63 women of child-bearing age. 63 women completed WFRs to assess iron intake as part of a study on iron deficiency. These women also completed the ACCVFFQ. Nutrient intakes were computed independently for the WFRs and FFQs. Intakes were compared as group means, by correlation and by quintile classification, adjusting for day-to-day variation in intakes, and for energy intake. Individual differences in results were also examined. The strongest associations between WFR and FFQ results were energy-adjusted, log-transformed and adjusted for day-to-day variability in intake. Correlation coefficients ranged from 0.28 for vitamin A to 0.78 for carbohydrate. Mean intakes from the WFRs and FFQs were within +/- 20% for 21 of 27 nutrients. Poor agreement between FFQs and WFRs for retinol intake was due to the inclusion of liver in two WFRs, an item which is not included in the FFQ. The ACCVFFQ performs as well as other FFQs for which validation data are available. The relatively poor measurement of retinol is consistent with other data, and with the limited number of foods in which this nutrient is abundant. The availability of an optically scannable valid instrument for assessing dietary intake will facilitate epidemiological studies of diet and disease, an area of current research priority.