REPRODUCIBILITY OF SELF-REPORTED PAST BODY-WEIGHT

Objective: To examine the reproducibility of self-reported past body w eight for ages 25 and 40 y and effects influencing recall of body weig ht. Design and Subjects: Repeated administration of a computer-guided interview including questions on past body weight for 25 and 40 y of a ge to 120 middle-aged participants of a validation study on dietary as sessment methods at the EPIC-Potsdam study centre. Recall error was de fined as difference in body weight reported in the second compared to the first interview. Reproducibility of recall of body weight was asse ssed by plotting the difference between the interviews against the mea n of the recalled weight. Possible influences of sex, age, measured cu rrent body weight, current body mass index, and highest education atta ined on recall error were examined. Results: Mean difference in recall ed body weight was small, but variation of differences was considerabl e. Classification into recall error strata demonstrated reproducibilit y of weight recall within +/- 3 kg for 75.8% for weight recall for age 25 y and 81.7% for age 40 y, respectively. Absolute recall error was not influenced by age, sex, current body weight, current BMI, and educ ational attainment. Conclusions: We observed a high degree of reproduc ibility of self-reported past body weight for ages 25 and 40 y between the two interviews administered With respect to reproducibility admin istration of a single questionnaire or interview to obtain information on past body weight thus seems to be sufficient.