Hormone Replacement Therapy (HRT)
In women going through the menopause, hormone replacement therapy (HRT) is very effective in reducing the distressing hot flushes that are commonly experienced, and there is some evidence that it may help to prevent osteoporosis (bone thinning).
Gradually, more and more beneficial effects were claimed for HRT, including prevention of heart attacks and stroke. And millions of women, advised by their doctors, began using HRT for longer because of claims of these and other extra benefits.
No wonder she was confused
In January 2004, a hysterectomy patient wrote this letter to The Lancet:
Then, in 1997, there was a warning that the advice might be wrong: researchers from Finland and the UK reviewed, systematically, the results of well-conducted studies. They found that, far from reducing heart disease, HRT might actually increase it. Some prominent commentators dismissed this conclusion, but its tentative result has now been confirmed by two large well-conducted trials.
Had the effects of HRT been assessed properly when it was first introduced, women would not have been misinformed and many of them would not have died prematurely. To make matters worse, we now know that HRT increases the risk of stroke and of developing breast cancer. 
Overall, HRT continues to be a valuable treatment for women with menopausal symptoms.  However, it is tragic that it was so heavily promoted specifically as a way of reducing heart attacks and stroke. Although the increased chance of these serious conditions is modest, the total number of women affected is very large indeed because HRT has been so widely prescribed.
GET-IT Jargon Buster
GET-IT provides plain language definitions of health research terms