Effects of Procedural Differences between 1977 and 1987 in the Nationwide FoodConsumption Survey on Estimates of Food and Nutrient Intakes: Results of the USDA 1988 Bridging Study

摘要

The 1988 Bridging Study was conducted to facilitate the comparison of the resultsfrom the U.S. Department of Agriculture's 1987-88 Nationwide Food Consumption Survey (NFCS) with results from the 1977-78 NFCS. A field experiment was designed using a split-sample approach to test the effects of changes in interview, food coding, and weight conversion procedures and in the nutrient data base on estimates of mean intakes of food energy and the 14 nutrients reported in 1977-78: fat, protein, carbohydrate, calcium, iron, magnesium, phosphorus, thiamin, riboflavin, niacin, and vitamins A, B-6, B-12, and C. Women 20 to 49 years of age were randomly assigned to one of two treatment groups. A 24-hour recall was administered to Group A (N=348) using 1987-88 interview procedures, and their nutrient intakes were calculated using the 1987-88 food codes, weigh conversions, and nutrient data base. Group B (N=349) was interviewed using 1977-78 procedures; dietary recalls were coded twice independently, using 1987-88 and 1977-78 food codes. Group B nutrient intakes were calculated four ways using various combinations of 1987-88 and 1977-78 food codes, weight conversions, and nutrient data bases.