Clinical Studies of Oestrogen Therapy for Dementia

Abstract

The positive effects of oestrogen on the maintenance of brain function and the prevention of Alzheimer's disease (AD) have recently been reported. Oestrogen is considered to 1) improve depression, 2) increase brain blood flow, 3) stimulate neuronal function, 4) increase the number of developed gliacytes, and 5) suppress amyloid deposition and protect from the oxidative stress induced by amyloid deposition. The use of hormone replacement therapy (HRT) for the prevention and treatment of AD has received considerable attention. Treatment with conjugated equine oestrogens 0.625mg daily produces improvement during the third week, and this is maintained for as long as therapy is continued. Medroxyprogesterone acetate seems to have an unfavourable effect on AD, causing a depressive status. Therefore systemic oestrogen treatment with vaginally administered progesterone for endometrial protection may be a suitable combination for non hysterectomised women with AD. Recent epidemiological studies have suggested that oestrogen use is associated with a reduction in the relative risk of AD with greater protection with increasing dose and duration of use.