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Brain Shrinkage Seen with Hormone Replacement Therapy

Jan 14, 2009 | Parker Waichman Alonso, LLP

Much has come out about the risks of hormone replacement therapy (HRT)  drugs like Premarin and Prempro, especially as a result of the massive Women’s Health Initiative (WHI) study.  Now, it seems that HRT may shrink the brain.

According to two studies that reviewed the same group of women, while HRT does seem to shrink the brain, it has not yet been linked with early cerebrovascular disease, said HealthDay News.  In other words, HRT affects the size of the brain but does not seem to contribute to so-called “silent strokes.”  Both studies were published in the January 13 issue of Neurology.

"These are a nice companion to cognitive studies reported earlier. This is now neuroradiological evidence that, together, suggest that the effect [of hormones] may be more degeneration than vascular," said Miriam Weber, an assistant professor of physical medicine and rehabilitation and of neurology at the University of Rochester Medical Center, according to HealthDay News.

Last year, Reuters reported that historically, doctors believed HRT could protect women from chronic diseases, especially heart disease.  But use of HRT plunged after the 2002 Women's Health Initiative study found that HRT could raise the risk not only of breast and ovarian cancer, but also of strokes and other serious conditions.  Research since also indicates that the incidence of breast cancer dropped by 8.6 percent between 2001 and 2004 in the United States, in conjunction with the decline in HRT use.  HealthDay News also noted that in addition to an increased risk of stroke and cerebrovascular disease in post-menopausal women on HRT, the WHI Memory Study found that post-menopausal women on HRT suffered from “an increased risk of dementia and memory problems.”

The two new studies were conducted to look at the link between a higher risk of dementia and women being treated with CEEs—conjugated equine estrogens, which is hormone treatment with either estrogen or estrogen plus progestin.  In the first, the team looked at brain scans from 1,400 women who took part in WHI’s Memory Study.  Those women had been on HRT fro between four and six years, said HealthDay News.  The second study looked at MRI scans from the same population, who HealthDay News said, is now between 71 and 89 years old, and found brain shrinkage in both the hippocampus and frontal lobe area.  Both areas have to do with memory and cognitive function, said HealthDay News.

"Much to our surprise, we found a small but significant decrease in the hippocampal and frontal volumes, and a nonsignificant trend towards reduced total brain volume in women who had been randomized to hormone therapy," reported Susan M. Resnick, lead author of the second paper and a senior investigator with the Intramural Research Program at the U.S. National Institute on Aging, quoted HealthDay News. "The negative effects were most evident in women who already may have had some memory problems before using hormone therapy … so, it suggests that hormone therapy may be accelerating processes that have already begun."  Also, it seemed that the HRT effect was especially significant in women with more brain lesions, "… in women who were already having some problems, the hormone therapy did have an adverse effect," Resnick said.