Informants' knowledge of reproductive history and estrogen replacement

Background. There has been much interest in assessing estrogen use in healthy older women and those with Alzheimer's disease. However, data for the women with Alzheimer's disease must be obtained from an informant. The aim of this study was to better understand what informants are likely to know about reproductive history and estrogen use. Methods. Reproductive history data from informants of Alzheimer's patients were modeled by comparing responses from 40 cognitively healthy older women with that of a designated informant. The designated informants were similar in demographics to informants for patients with Alzheimer's disease. Results. Informant data regarding reproductive history was likely to be accurate, when known. However, 30% of the subjects did not identify an informant who had personal knowledge of them. Of those informants who had personal knowledge of the subject, accuracy for those who reported that they knew the information varied depending on the aspect of reproductive history assessed (age of menarche, 29%: age of menopause, 20%: pregnancies, 67%: live births. 92%: hysterectomny. 92%: and postmenopausal estrogen use. 82%). Daughters served as the most likely and most accurate informants in this study. Conclusion. This study demonstrates that information obtained from informants for patients with Alzheimer's disease is likely to be accurate for some but not all aspects of reproductive history. Of concern for such studies will be the 30% of patients who do not have an informant with personal knowledge about them.