Thursday, November 18, 1999 Published at 01:12 GMT
Hormones may protect against Alzheimer's
Very few middle-aged women develop Alzheimer's disease
The hormone oestrogen may protect younger women who are at risk of developing Alzheimer's disease, according to new research.
A report, published in the Journal of Neurology, Neurosurgery and Psychiatry, may open the door for wider testing of the hormone on all forms of the degenerative brain disease.
Normally, Alzheimer's is a condition which progressively affects much older women, but in some cases, the diagnosis can be made well before the age of 60.
Early-onset Alzheimer's disease is thought be genetically determined, but evidence that the hormone maycause a delay could be valuable to scientists searching for clues to its development.
The researchers looked at data from patients in the Netherlands who were diagnosed between 1980 and 1987.
Close relatives provided information about oestrogen use, whether through the contraceptive pill or via hormone replacement therapy following the menopause.
The findings showed oestrogen reduced the risk of developing early-onset Alzheimer's disease by a third.
Stops hardening of arteries
The authors of the study suggested that as oestrogen may protect against the hardening of the arteries, the blood supply to the brain in women taking the hormone may be better than those not taking oestrogen.
They also theorise that the hormone may act on the nervous system and promote growth factors which keep the brain healthy.
Oestrogen may even prevent the deposition of a protein on the brain - a feature which characterises the disease in brain scans of Alzheimer's patients.
There have been other studies looking at the link between oestrogen use and late-onset Alzheimer's disease.
Although a few suggest there is no benefit to be gained, overall, they also point to a third less risk of developing the disease.
Dr Richard Harvey, Director of Research at the Alzheimer's Disease Society, said the findings added to the weight of research indicating a link between oestrogen and protection from all forms of the disease.
He said: "You have to be very careful about using this to promote the use of oestrogen for early-onset Alzheimer's which is a very rare disease.
"But this is a very helpful new study. What we need now are clinically controlled trials."
Oestrogen therapy following the menopause is known to extend the protection against coronary heart disease a woman naturally enjoys prior to the menopause.
But oestrogen-only hormone replacement therapy is known to slightly increase the risk of developing gynaecological cancers such as endometrial cancer.
Contraceptive pills which contain oestrogen also increase the risk of deep vein thrombosis.
Although there are some treatments available which appear to slow the progression of Alzheimer's, nothing which reverses the condition has yet been found.