THE VALIDITY OF SELF-REPORTS OF PAST BODY WEIGHTS BY US ADULTS

Past weight or patterns of weight change may be more important to chro nic disease risk than current weight. Self-reports, however, are often the only source of information about past body weight. To date, very few studies have examined factors affecting the validity of self-repor ted past body weight. We examined the validity of self-reported past b ody weights of 1,931 U.S. adults who were participants in the First Na tional Health and Nutrition Examination Survey (1971-1975) and were in terviewed again in the National Health and Nutrition Examination Surve y I Epidemiologic Follow-up Study (1982-1984). We compared the body we ight measured during the initial examination (1971-1975) with the reca lled 1971-1975 body weight reported during the follow-up interview (19 82-1984). Recalled past weight was strongly correlated with previously measured weight (r = 0.13 for men, and r = 0.74 for women). Men overe stimated their past body weight, whereas women underestimated their pa st weight. Although 39% of men and 41% of women estimated their past w eight within 5 pounds, approximately 17% of women and 10% of men under estimated their past weight more than 15 pounds. Accuracy of reporting was influenced by sex, race, current body mass index, and the amount of weight gained over the 10 years following the initial examination. These factors should be considered when using recalled weight in epide miologic studies.