Neurobiological consequences of long-term estrogen therapy

Postmenopausal women demonstrate an increased incidence of Alzheimer's disease (AD). Epidemiological evidence suggests that estrogen replacement therapy (ERT) may reduce the risk or delay the onset of AD, yet recent clinical trials found no cognitive benefits of ERT in women with mild to moderate AD. This review suggests that the timing of estrogen administration may explain these conflicting results. Chronic administration has neurobiological consequences that can affect neural and immune function, but a therapy designed to mimic the natural cycle of fluctuating hormones may more effectively slow the progression of AD in postmenopausal women.