Aging Begins at 30

Brain Effects of Hormone Replacement in Women

Now we have the Women's Health Initiative Investigators (WHI) report on the incidence of probable dementia and mild cognitive or learning difficulty. It was a randomized, double blind, placebo-controlled clinical trial in 4,532 women, age 65 or older, who received daily tablets of estrogen and progesterone (Prempro) or an identical looking placebo or "sugar pill." Cases of dementia were found in ten percent over 65 and 50 percent over 85. When separated, 66 percent of the dementia cases were in the treated group compared to 34 percent in the placebo group. Also, these hormones did not prevent milder learning difficulty called in the medical jargon, cognitive impairment. The risk of dementia in the hormone treated group was therefore twice that in the women receiving the placebo, which in retrospect was found to begin about a year after the start of the study. Could it have been due to "silent" infarcts (death of brain cells) or strokes caused by blocking of the blood supply?

The study was stopped at 5.6 years after the start rather than the planned 8.5 year trial. This does not mean that estrogen alone (without the progesterone) does not prevent these problems and such a test is continuing. Prior tests with estrogen alone were cross sectional, (20 patients at 70 and another 20 at age 80, etc.) and not the same 20 women at 70 and 80. These tests have been suggestive but, often have not been done for long enough and had too few patients.

In a second study (in the same issue of the JAMA) 4,381 women were studied by annual global learning or cognitive tests. Women receiving estrogen and progesterone had a substantial and meaningful decline in their mental tests in seven percent compared to five percent in the placebo treated controls.

In a third study of 16,608 different women aged 50 to 79, attention was paid to the occurrence of strokes (both for severity and type of cause). The types were blood blockage (called ischemic) in 80 percent and into-the-brain bleeding (hemorrhagic) in the other 20 percent. An excess risk of stroke was seen in all age groups in the women receiving the hormone replacements, which amounted to a 41 percent increase in strokes over a five-year period. The increase took a year to begin to appear. So hormone replacement treatment increased the risk of stroke in healthy postmenopausal women. There was no noted increase in blood pressure. This finding parallels the increase of stroke risk already known to affect women taking oral contraceptives.

Most women should not be taking hormone replacement except in low doses, for the treatment of acute menopausal symptoms, and it should be taken for less than two years. Strokes are the third leading cause of death in the United States and the leading cause of disability. Again the study of estrogen alone possibly preventing strokes continues.

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See related Patient Topics Endocrine System (Hormones), Hormone Replacement Therapy, Procedures and Therapies or Women's Health.

See related Provider Topics Endocrine System (Hormones), Procedures and Therapies or Women's Health.

All contents copyright © 1992-2004 the Author(s) and The University of Iowa. All rights reserved.

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