PRECISION AND ESTIMATED ACCURACY OF 2 SHORT-TERM FOOD FREQUENCY QUESTIONNAIRES COMPARED WITH RECALLS AND RECORDS

Two widely used food frequency questionnaires (Block FFQ, Willett FFQ) were modified to reflect intake over the past 7 days and compared to intake information gathered from diet records and 24- hr recalls cover ing the same 7-day period. The Block FFQ and the Willett FFQ were also gathered at the beginning of the assessment period to reflect the 7-d ay period of time before records and recalls were gathered. Fifty six subjects were assigned to either recording diet for 3 days, recording diet for 6 days, or providing three 24-hr recalls. Results indicate si milar levels of within-method test-retest reliabilities for 3-day RECO RDS and 6 day RECORDS, and within the two Block FFQs and within the tw o Willett FFQs from each subject, while lower reliabilities were seen in 24-hr RECALLS. When the FFQs were compared to the 6-day RECORDS wit h between-method agreement coefficients, there was a moderate level of agreement, with most values between 0.5 and 0.8 for both FFQs. Signif icant differences between mean levels of nutrients estimated by the th ree methods indicated differences only in the estimates of carbohydrat e and vitamin A. The use of FFQs to gather short-term intake informati on is discussed.