The study involved 95 women with an average age of 53 who recently went through menopause. The women had magnetic resonance imaging, or MRIs, taken of their brains at the start of the study. They then received a placebo, oral hormone therapy or the hormone skin patch. They had MRIs periodically over the next four years.
During the study, women with higher levels of thrombogenic microvesicles, the platelets more likely to cause blood to clot, were likelier to have higher increases in the amount of white matter hyperintensities (shown as concentrated white areas on an MRI scan), which may lead to memory loss.
"This study suggests that the tendency of the blood to clot may contribute to a cascade of events leading to the development of brain damage in women who have recently gone through menopause," says study author Kejal Kantarci, M.D., of Mayo Clinic. "Preventing the platelets from developing these microvesicles could be a way to stop the progression of white matter hyperintensities in the brain."
All of the women had white matter hyperintensities at the start of the study. The amount increased by an average volume of 63 cubic millimeters at 18 months, 122 cubic millimeters at three years and 155 cubic millimeters at four years.
The study was supported by the National Institutes of Health (grants NS66147, HL90639, AG040042, RR024150, TR000135, HD65987 and AG044170), Aurora Foundation and Mayo Foundation.