Hormones linked to brain tissue loss in older women

Taking hormones after menopause appears to accelerate loss of brain tissue in women over 64, which may explain why the therapy had previously been linked to an increased risk of dementia and mental decline in elderly women.

Hormones linked to brain

The brain-volume findings, published in yesterday’s issue of Neurology, are the latest from the Women’s Health Initiative, a landmark government study of postmenopausal women. Over the past six years, it has firmly established that, contrary to decades of conventional wisdom, the risks of hormone therapy outweigh the benefits.

Yesterday’s finding also came with a surprise. Researchers had theorized that supplemental estrogen, with or without the synthetic hormone progestin, caused memory and thinking problems by triggering tiny, symptomless strokes. But the new research, which involved magnetic resonance imaging (MRI) of the brains of 1,400 Women’s Health Initiative participants, linked cognitive problems to brain shrinkage – not strokes.

a National Institute on Aging neuropsychologist who conducted the new research.

Like many other scientists, Resnick conducted studies in the 1990s that suggested hormone therapy could ward off dementia, even Alzheimer‘s disease. The Women’s Health Initiative was the first huge study to randomly assign to women to take hormones or a placebo, then follow them for years.

For the new analysis, MRIs were conducted and read by University of Pennsylvania radiologists who had no idea which women had taken hormones and which had taken placebo.

The women were at least 65 when they joined the study, and took hormone therapy or placebos for four to six years.

The two groups had no differences in the amount of brain scarring, a sign of strokes. The hormone-takers, however, had significant changes in the frontal lobe and the hippocampus, two areas critical to thinking and memory. Compared with nonhormone-takers, these women had small but significant losses in volume in these two areas.

Women who had scored poorly on mental-function tests when they enrolled in the Women’s Health Initiative had the greatest shrinkage of their hippocampus. Resnick and her co-authors speculate women with the greatest loss were already suffering from a neurodegenerative disease process that hormone therapy worsened.

Exactly how remains unclear. Hormone-therapy formulas contain so many chemical components that pinpointing a potentially toxic one is difficult.