Menopause Hormones Linked to Women's Increased Alzheimer's Disease Risk

The menopause could raise a woman's risk of developing Alzheimer's disease due to hormonal changes, according to a study.

It is already known that women are more likely to have Alzheimer's than men, making up two thirds of those living with the neurocognitive disorder worldwide. To try to explain why, scientists studied 85 women and 36 men aged between 40 to 65-years-old, who didn't have any cognitive problems.

Researchers collected and compared information about the participants' lifestyle and health, and examined them mentally and physically. This included carrying out MRI scans, and PET scans that detect amyloid plaques and tau protein tangles which are hallmarks of Alzheimer's disease.
The findings published in the journal Neurology showed that women who had experienced the menopause were more likely to have risk factors for Alzheimer's disease.

Women scored worse than men in four biomarkers of Alzheimer's disease measured in the study. They had 30 percent more beta amyloid plaques in the brain, on average, and their brains didn't process sugar as well. The women also had 11 percent lower average levels of gray and white matter.

The abnormalities were strongest in those who had reached menopause, followed by those on hormone replacement therapy, those who had a hysterectomy, and women diagnosed with thyroid disease.

Co-author Lisa Mosconi, associate director of the Alzheimer's Prevention Clinic of Weill Cornell Medical College, said in a statement that the general thinking has been that women are more likely to develop the disease because they tend to live longer, but their research suggest this may not be the case.

"Our findings suggest that middle-aged women may be more at risk for the disease, perhaps because of lower levels of the hormone estrogen during and after menopause.

"While all sex hormones are likely involved, our findings suggest that declines in estrogen are involved in the Alzheimer's biomarker abnormalities in women we observed." In particular, the loss of gray matter has overlaps with the brain's estrogen network, she said.

The study suggests there may be a window of opportunity to prevent Alzheimer's in women early in their hormonal aging process, the authors said.

Sara Imarisio, head of research at Alzheimer's Research UK who did not work on the study, told Newsweek: "This research used a comprehensive set of brain scans in people who did not have memory or thinking problems, but this study was relatively small and larger studies will be needed to confirm these findings.

"While women in the study were more likely to show brain changes usually associated with Alzheimer's, we do not know whether they would have gone on to develop symptoms of dementia. Although the researchers found that the menopause was the strongest predictor of these changes aside from sex, they cannot tell if this was down to hormone changes alone, as they did not measure this directly."

Imarisio said there is no sure-fire way to prevent dementia, of which Alzheimer's is the most common form, but generally what is good for the heart is good for the brain.

"The best current evidence indicates as well as staying physically and mentally active, eating a healthy balanced diet, not smoking, drinking only within the recommended limits and keeping weight, cholesterol and blood pressure in check are all good ways to support a healthy brain as we age," she said.

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A stock image shows a woman having a PET scan. Getty