Review on February 04, 2010
Alzheimer disease (AD) is the most established form of dementia among the elderly and affects females more often than males. Despite contrasting evidence, many studies indicate that hormone therapy could lower the risk for or delay the onset of Alzheimer's in women who have experienced menopause and menopausal symptoms.
This article reviews the neuroprotective and neurotrophic effects of estrogen, focusing on brain regions involved in learning and memory. It looks at data regarding the success of estrogen replacement therapy/hormone therapy in preventing or delaying the beginning of Alzheimer's in women who have been through menopause and experienced menopausal symptoms and it also evaluates the emerging research on the use of estrogen to treat this particular type of dementia.
Due to the fact that Alzheimer's is most usual in women, it could be argued that reduced estrogen levels are associated with the decline in cognitive function linked to this form of dementia. Reduced estrogen levels after menopause and menopausal symptoms are a risk factor for Alzheimer's, and neurobiological reviews have found a link between estrogen and learning and memory capacity.
The majority of studies have reported that estrogen replacement therapy has positive effects on learning and memory in females that have experienced menopause and menopausal symptoms. Moreover, hormone therapy is related to a reduced risk for Alzheimer's, although various investigations failed to find notable effects. Without large randomized studies it is difficult to confirm the use of estrogen hormone therapy to prevent or defer Alzheimer's in postmenopausal women who have experienced menopausal symptoms. There is also doubt regarding the beneficial effects of estrogen hormone therapy on cognitive function occurring right after menopause and menopausal symptoms or later in life, and whether estrogen is successful in stopping the cognitive deterioration observed in normal aging and/or in pathological conditions.
It's possible that estrogen is most effective in inhibiting Alzheimer's immediately or shortly after menopause and menopausal symptoms. Many observational studies have suggested a considerable likelihood for the development of Alzheimer's among women that have used estrogen replacement therapy after menopause and menopausal symptoms. The Women's Health Initiative Study of Cognitive Aging, a randomized, placebo-controlled trial will assess cognitive outcomes with estrogen replacement therapy use, is likely to contribute a great deal of evidence about the influence of estrogen-based hormone therapy on cognition and Alzheimer's in women who have experienced menopause and menopausal symptoms. This review is one of many large clinical studies that will produce vital data about the possible effects of estrogen replacement therapy on preserving cognitive function in women who have experienced menopause and menopausal symptoms.
At the moment most observational evidence, supported by neurobiological research findings on the function of estrogen, indicates that Estrogen Replacement Therapy/Hormone Therapy eases the degeneration that may lead to Alzheimer's. Insufficient evidence into estrogen's role in treating this type of dementia suggests that hormone therapy should begin straight after menopause and menopausal symptoms wherever possible, before the onset or development of the disease. To summarize, the relationship of hormone therapy after menopause and menopausal symptoms to Alzheimer's can be compared to its relationship to osteoporosis in that hormone therapy appears to have a role in primary prevention.
- JAMA - The Journal of the American Medical Association - Arch Intern Med. 2005;165:2063-2068