Comparison of recalled and validated oral contraceptive histories

From a case-control study of the relation between oral contraceptives and breast cancer carried out in East Germany during 1982-1986, the authors obtained information on oral contraceptive use through interviews of study subjects and from the records of prescribing gynecologists. The degree of agreement regarding information from these two sources was assessed for 234 breast cancer cases and 524 controls who had ever used oral contraceptives. Agreement between information obtained from medical records and that from interviews on total duration of use, number of episodes of use, and time since first and last use was reasonably good, and levels of agreement did not differ appreciably between cases and controls. Lower levels of agreement were observed for individual brand names and the duration of use of specific brands. Attempts should be made to obtain information on specific brands from medical records when investigating the effects of individual preparations.