Could Menopause Explain Why Alzheimer's Disease Is More Common in Women?
Here’s how the brain changes with menopause and how you can reduce your risk of Alzheimer’s.
Menopause is a natural part of aging for about half the population. It marks the end of fertility, as the ovaries gradually reduce sex-hormone production and monthly periods cease. But menopause is also a focus for researchers who are trying to unravel one of medicine's ongoing mysteries: Why is it that almost two-thirds of people with Alzheimer's disease are women?1
Alzheimer's disease (AD) is the most common type of dementia—which is the progressive loss of memory and other brain functions.2,3 Symptoms of AD can interfere with daily life and include repeated memory loss, difficulty having conversations, and frequently making poor decisions.4,5
Scientists don't yet fully know what causes Alzheimer's disease, but they have found that a combination of different factors, from biological to lifestyle, could increase your risk of developing it.4
"We have known for decades that, after getting older, simply being a woman is the major risk factor for Alzheimer's disease," said Lisa Mosconi, PhD, an associate professor of neuroscience in neurology and radiology at Weill Cornell Medicine. Scientists used to think this was because women tend to live longer than men, but now hormones are believed to play a major role, said Mosconi. "Our research points to menopause as an activating factor."
Menopause as a Potential Risk Factor for Alzheimer's Disease
Menopause transition, or perimenopause, often begins around ages 45–55 and can last up to 7–14 years.6 During this time, the ovaries gradually produce less sex hormones, such as estrogen and progesterone. These are the same hormones that rise and fall during a typical menstrual cycle. Once females reach menopause, about a year after their last menstrual period, the ovaries stop working.
But as the ovaries change during and after menopause transition, the brain changes as well.5
"Many of the symptoms of menopause—the hot flashes (a rise in body temperature), night sweats, anxiety, depression, insomnia, brain fog, memory lapses—don't start in the ovaries; they start in the brain," said Mosconi.
However, researchers don't know if symptoms of menopause can be used to predict Alzheimer's disease later in life, said Mosconi.
What scientists do know is that natural levels of estrogen and progesterone can help protect the brain. There are specific proteins in your brain that interact with these hormones, and your brain also produces its own estrogen and progesterone—just not as much as the ovaries do.7,8 The decline of sex hormones in menopause transition can lead to changes in the brain.
Ideally, to study whether menopause is a risk factor for Alzheimer's disease, researchers would need to examine the same group of women from their early 50s (average start of perimenopause) up to their early 70s (average start of AD), explained Mosconi, who is also the director of the Alzheimer's Prevention Program at New York Presbyterian Hospital and Weill Cornell Medical Center. But that kind of long-term study is still to come.
Brain Changes with Menopause
Currently, several researchers are exploring signs of early dementia in the female brain which can show up years before AD symptoms surface, said Mosconi.
One of the signs of Alzheimer's disease that they previously looked for was increased amounts of beta-amyloid proteins in brain regions that control memory. Researchers used to think these proteins played a primary role in AD, based on a 2006 breakthrough study published in Nature. However, this July, a Science investigation reported on the potential fabrication of evidence from this study. Further investigations are ongoing, and it's currently unclear whether beta-amyloid proteins play a role in Alzheimer's disease.
