Hormone replacement therapy (HRT)

HEART DISEASE

Estrogen helps decrease "bad" cholesterol and increase "good" cholesterol in the bloodstream. Because lower levels of "bad" cholesterol and higher levels of "good" cholesterol are associated with a decreased risk of heart disease, researchers thought that HRT should lower risk by changing these levels.

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However, the WHI has shown that this is not true. The number of heart attacks actually increased 29% among women taking estrogen and progestin. Put another way, WHI researchers estimate that 37 of every 10,000 women taking HRT will have a heart attack, while 30 in 10,000 not taking HRT will have a heart attack.

The Heart Estrogen/progestin Replacement Study (HERS) published earlier in 2002 also showed no benefit for the heart of taking estrogen and progestin. These women were followed for almost 7 years.

HRT should not be given strictly for the prevention of high cholesterol or heart disease. Generally, lifestyle changes and medications to lower cholesterol and control blood pressure are recommended for those conditions.

STROKES

The WHI study showed a 41% increase in strokes among the women taking estrogen/progestin. For every 10,000 women taking HRT, 29 will have a stroke, compared with21 in 10,000 women not taking HRT.

An increased risk of stroke was also seen in the estrogen-only therapy.

BLOOD CLOTS/THROMBOEMBOLIC DISEASE

The increased risk of blood clots from taking estrogen has been recognized for years. Generally, this risk has been associated with the use of oral contraceptives that contain high doses of estrogen. It is further increased for women who smoke cigarettes.

The WHI study confirmed an increase in the number of blood clots in women taking estrogen/progestin. For every 10,000 women taking HRT, 34 will develop clots in their lungs or legs, while 16 in 10,000 not taking HRT will develop blood clots.

OSTEOPOROSIS

A woman's body produces less estrogen during and after menopause, which may affect her bone strength. The WHI study showed that women taking HRT had 34% fewer hip fractures and 24% fewer fractures than women not receiving hormones.

However, the short-term use of HRT to relieve symptoms at the time of menopause does little to prevent fractures in women when they reach 75-80 years of age. Women who take estrogen to maintain bone density must continue taking estrogen because the beneficial effects on bones disappear when it is discontinued.

Women who are considering taking HRT to prevent osteoporosis should discuss with their physician their individual risk of coronary heart disease, stroke, blood clots, and breast cancer.