Hormone Therapy Linked to Brain Shrinkage

January 13, 2009
Shivani Parmar, MPH

Researchers have found data suggesting that frequently prescribed forms of postmenopausal hormone therapy may "slightly accelerate the loss of brain tissue in women 65 and older beyond what normally occurs with aging."

Wake Forest University Baptist Medical Center researchers have published new data in the January issue of Neurology suggesting that frequently prescribed forms of postmenopausal hormone therapy may “slightly accelerate the loss of brain tissue in women 65 and older beyond what normally occurs with aging.”

Earlier studies suggested that women undergoing hormone therapy had greater difficulty thinking or remembering and experienced greater dementia or cognitive impairment. This new study involved examining the MRI scans of more than 1,400 women, between the ages of 71 and 89, “who had previously participated in the WHI [Women’s Health Initiative] hormone therapy studies for an average of four to six years.” Researchers found that “women who had taken hormone therapy had slightly smaller brain volumes in two critical areas of the brain: the frontal lobe and the hippocampus.” Both of these areas in the brain are used for thinking and memory skills, and losing volume in the hippocampus is a known risk factor leading to dementia.

“Our findings suggest that hormone therapy in older post-menopausal women has a negative effect on brain structures important in maintaining normal memory functioning” said lead author Susan Resnick, PhD, of the National Institute of Aging. “However, this negative effect was most pronounced in women who already may have had some memory problems before using hormone therapy, suggesting that the therapy may have accelerated a neurodegenerative disease process that had already begun.”

This new data suggest that “older women who were already having some cognitive problems at the time they began hormone therapy are most at risk for negative effects on the brain.”

Researchers are currently preparing further research to study “whether the negative effects of hormone therapy on brain volumes continue over time through follow-up MRI studies of the women studied.” They also plan “to examine younger women who took hormone therapy closer to the timing of menopause to determine whether they show a different pattern of effects on cognitive function and brain structure.”

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