Estrogen Use in Protection From Cognitive Decline

Inclusion Criteria:

   - Women between the ages of 45 and 65

   - Currently on hormone replacement

   - One year or more post complete cessation of menses

   - Willing to sign the Human Subject Protection Consent form prior to enrollment in the
   study

   - Willing to be randomized to continue or discontinue estrogen therapy

   - Adequately visually and auditorially acute to allow neuropsychological testing

   - Beyond 8 years of educational achievement to allow adequate neuropsychological testing

   - Willing to undergo brain imaging

   - At risk for cognitive decline, as defined by one or more of the following: Personal or
   family history of mood disorder, Hypothyroidism, Diabetes, Family history of
   Alzheimer's, APOE-4 allele

Exclusion Criteria:

   - Diagnosis of possible or probable Alzheimer's disease or dementia

   - Cerebrovascular disease or uncontrolled hypertension (systolic BP >170 or diastolic BP
   >100)

   - History of myocardial infarction within previous year or unstable heart disease

   - History of significant liver disease, pulmonary disease, or current cancer

   - Contraindication for MRI (metal in body, claustrophobia, etc.)