New findings challenge previous evidence that suggested that hormone replacement therapy has a protective effect on the brain

The findings, published in the Journal of the American Medical Association, state that oestrogen plus progestin therapy increased the risk for probable dementia in postmenopausal women aged 65 years or older. In addition, oestrogen plus progestin therapy did not prevent mild cognitive impairment in these women. These findings, coupled with previously reported WHI data, support the conclusion that the risks of estrogen plus progestin outweigh the benefits.

The Alzheimer's Society's view

Although there is a lack of consensus, many other studies indicate that hormone replacement therapy (HRT) may reduce the risk for or delay the onset of Alzheimer's disease in postmenopausal women. There is not a simple direct relationship between oestrogen (contained in HRT) and dementia.

The Alzheimer's Society does not endorse taking HRT as a way of reducing the risk of dementia. Using HRT as a treatment or preventative measure against Alzheimer's disease would mean giving women without symptoms drugs which in themselves can produce side-effects.

Women who are experiencing symptoms of the menopause need to carefully discuss the relative benefits and risks of hormone replacement therapy with their GP.

This is a complex treatment decision that needs to be based on thinking through how the known risks and benefits relate to all aspects of a particular woman's well being, including current health, symptoms and family history.

However, a single randomised trial can never provide completely conclusive evidence. Further trials, and much longer term follow-up of the women in this current study are needed to fully evaluate the real long term risks and benefits of HRT.

For more information go to the JAMA website.