Hormone therapy can double dementia risk

By MARTIN JOHNSTON and REUTERS

A type of drug used by thousands of New Zealand women has been found in a study to double the risk of developing dementia.

The United States study continues the bad news about combined hormone replacement therapy, used to relieve menopause symptoms and to help prevent bone-thinning osteoporosis.

The latest study found combined HRT doubled the risk for probable dementia in women 65 and older and did not prevent mild cognitive impairment. Translated to a population of 10,000 women taking the pills, that would mean an additional 23 cases of dementia a year.

The Ministry of Health said the study was further evidence that in most cases the risks of combined HRT outweighed the benefits.

Women over 64 taking the drugs should discuss the new evidence with their GPs to see if it was appropriate to continue, said senior medical adviser Dr Stewart Jessamine.

But the study's findings could not be assumed to apply to younger women, he said. In the US study of 4532 women free of probable dementia, Alzheimer's disease was the most common form of dementia found four years later in both of its groups - about half took combined HRT, the rest inert placebo pills.

In the combined HRT group, 40 women were diagnosed with probable dementia, compared with 21 of those taking the placebo.

"The overall individual risk to women is low, although there is reason for concern," said the lead researcher, Dr Sally Shumaker, of Wake Forest University in North Carolina. "Because of the potential harm and lack of benefit found, we recommend that older post-menopausal women not take the combination hormone therapy to prevent dementia."

The study, published in this week's Journal of the American Medical Association, notes that Alzheimer's afflicts about a tenth of people aged over 65 in the US.