New Study Reveals Connection Between Menopause and Alzheimer’s

By Sophie Marx

A new international study led by the University of Galway has identified a connection between earlier onset of menopause and a higher risk of developing dementia.

The research is founded on the striking disparity that women are approximately 1.6 times more likely to develop dementia than men.

It investigated potential contributing factors using decades of health data from the Framingham cohort, which Professor Emer McGrath of the University of Galway, first encountered during her medical training at Massachusetts General Hospital.

Despite awareness of sex and gender differences in Alzheimer’s disease, a comprehensive understanding of these variations presents a comprehensive gap of knowledge in the field.

As awareness of this spreads, the “emphasis on ensuring an appropriate representation of women and looking into sex-based differences in research studies,” as Professor McGrath described it, is reflected in increasing support by funding agencies.

“Funders are becoming more cognisant of this and are very supportive of this type of research studies. So, we’re going to continue to understand that knowledge gap and tackle why women are at a higher risk of dementia compared to men.”

Drawing on the Framingham cohort, and applying the cohort to the present study, women’s reproductive health was investigated in connection to a heightened risk of Alzheimer’s.

“In recent years I have been trying to understand the biology during the reproductive years in women, and if that somehow is implicated in dementia risk,” said Professor McGrath. “So, in this particular study, I looked at about 1,300 women from the Framingham Heart Study.”

“We looked at the number of reproductive factors, so the age that they had their first period, when they entered menopause, whether they ever used hormone replacement therapy after menopause, what their levels of oestrogen in the blood were like, and how many children they’ve had born alive.”

Next, hormonal and reproductive factors collected in the preliminary observations were related to signs of shrinkage captured on MRI brain scans.

The cognitive tests of reasoning and memory revealed a connection between performance, the number of children the women had given birth to, and their risk of developing Alzheimer’s disease.

“We found that the MRI brain scans of women who had had more children born alive showed less shrinkage. And we also saw that those areas where you tend to see the most shrinkage in Alzheimer’s disease weren’t really affected in those with more children.”

Looking at the levels of oestrogen connected to menopause, the team concurred that higher oestrogen exposure throughout a woman’s life appeared to have protective qualities for cognitive health.

“We found that women who had higher oestrogen levels in the blood, who entered menopause later, so over the age of 52, or women who used hormone replacement therapy also tended to have better cognitive function.”

“And then when we looked at dementia, which was in a slightly smaller sample, we saw that women who had entered menopause at a younger age than 49 had a higher risk of dementia.”

When examining the potential impact of hormone replacement therapy, the inherent limitations of an observational study become apparent. Thus far, causality has not been proven.

“It doesn’t prove cause and effect; no observational study can do that. For now, it causes merely a suggestion that hormone replacement therapy may have benefits,” expands Professor McGrath.

In the meantime, until a clinical trial confirms Alzheimer’s preventative measures tailored to women’s bodies, general measures can be helpful to remember. This includes a healthy lifestyle, as well as having good social networks and remaining engaged in our communities.