PRESENTATION - A COMPARISON OF 2 METHODS TO ASCERTAIN DIETARY-INTAKE - THE CARDIA STUDY

Data on dietary intake were collected in the Coronary Artery Risk Deve lopment in Young Adults (CARDIA) Study at the baseline examination in 1985-86 and again at the second examination 2 years later. At baseline , a diet history questionnaire developed for the CARDIA study was used ; at the second exam the NCI (Block) food frequency questionnaire was used. The purpose of the present report is to compare the estimated nu trient intakes obtained with the two instruments; to compare correlati ons of nutrient intakes obtained at the two exams with those observed for other lifestyle and physiological variables also measured 2 years apart; and to assess ability to test hypotheses relating a-year change s in risk factors to between-exam differences in reported nutrient int akes. Mean levels of reported intake were generally greater for both b lacks and whites on the CARDIA diet history than on the Block food fre quency. Rank order correlations of reported nutrient intakes between t he two questionnaires indicated greater consistency between instrument s for whites (r's ranging between 0.35 and 0.52) than for blacks (r's ranging between 0.29 and 0.45). Correlations over time for nutrients w ere smaller than those observed for body size measures and lipid level s but were similar in magnitude to those for blood pressure, physical activity, and life events. At both exams, total caloric intake was pos itively associated with physical activity (range of r's for CARDIA wer e 0.07 for white women to 0.23 for black men, the range of r's for Blo ck were 0.06 for women to 0.11 for white men). Using data from the two examinations, 2-year changes in total plasma cholesterol were signifi cantly related to 2 year changes in Keys scores. The results of this c omparison are useful in that they show similarities and differences be tween two instruments developed to gather dietary intake data. The stu dy also illustrates the need to monitor young adults during a time whe n rapid changes occur in many lifestyle and physiologic factors.