Scientists from Weill Cornell Graduate School of Medical Sciences in New York have revealed that women are more prone to Alzheimer’s disease than men due to the menopause.
Until now experts had thought more suffer from the devastating form of dementia because women live longer than men.
Scientists found changes in hormone levels, in particular the loss of oestrogen due to menopause, could explain why.
Analysis of brain scans of 85 middle aged women and 40 men saw marked differences in four key indicators of increased disease risk.
Women scored lower than men in all four categories, with on average 30% more amyloid-beta plaque and 20% less glucose processing power.
Men were also found to boast 10% higher volumes of both grey and white matter.
Study author Dr Lisa Mosconi, of the Weill Cornell Graduate School of Medical Sciences in New York, said: “Our findings suggest that middle-aged women may be more at risk for the disease, perhaps because of lower levels of the hormone oestrogen during and after menopause.
“While all sex hormones are likely involved, our findings suggest that declines in oestrogen are involved in the Alzheimer’s biomarker abnormalities in women we observed.”
Nearly a million people in the UK live with Alzeihmer’s – the most common type of dementia, 65% of whom are women.
More than half a million people died from dementia and Alzheimer’s in England and Wales last year.
Researchers conducted magnetic resonance imaging (MRI) and positron emission tomography (PET) scans to see if the participants had any amyloid-beta plaques in their brain, a strong indicator of Alzheimer’s disease.
The four key brain areas assessed were the volume of grey and white matter, the level of amyloid-beta plaques and how quickly their brain processed glucose, another indicator of healthy brain activity.
Researchers found that the menopause was the strongest predictor of these changes aside from sex.
The findings, published by the journal Neurology, did not confirm whether the changes were down to hormone changes alone.
Dr Sara Imarisio, research head at Alzheimer’s Research UK, said: “It’s a fact that more women are affected by dementia than men.
“While women can expect to live longer than men, this alone does not explain the difference in the numbers developing dementia.
“This research used a comprehensive set of brain scans in people who did not have memory or thinking problems.
“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.”