New Evidence on Why Women are More Likely to Get Alzheimer’s

Women generally live longer than men. And it used to be thought their longevity was the reason they developed Alzheimer’s disease more often than men. They simply lived longer. Men died sooner, from other medical issues.

That belief is now being challenged. Women may be genetically more disposed to this medical problem. Here’s what researchers are finding. . .

Scientists are now zeroing in on structures in women’s brains that make them more vulnerable to debilitating memory loss. They haven’t completely explained this vulnerability, but they understand a lot more about it than they used to.

And they’ve found plenty of reason to argue that women have greater need to lead a lifestyle that lowers the risk of Alzheimer’s. I have a couple of suggestions on that, but first let’s look at the findings on gender-based risk. . .

Risks Unique to the Female Brain

The statistics on Alzheimer’s in women are pretty stark:

As a woman enters her sixties, she has twice the risk of getting Alzheimer’s disease than she has of getting breast cancer.
Women represent 64 percent – nearly two-thirds — of the people in the United States today who have Alzheimer’s. Men account for only 36 percent.
When he reaches age 65, a man has a nine percent chance of developing Alzheimer’s during his lifetime. Women run twice that risk.

Now, if you’ve been following the research on Alzheimer’s, you know that the science is still murky about the physical developments in the brain that are the true root cause of the disease. But the difference between men and women may have to do with those perennial suspects, beta and tau proteins.

The well-known beta-amyloid plaque and tau tangle theories have been under fire lately – for good reason. You can count me among the doubters. The accumulation of these toxic proteins among the brain cells is sometimes associated with dementia, but not always, and meanwhile many people with the plaques and tangles die with full possession of their memory and cognitive abilities.

A New Understanding of the Toxic Proteins

The initial buildup of these proteins is a not sure sign that a person will develop Alzheimer’s, but now there are new findings that suggest they play a role. There may be some life in the plaques-and-tangles theory after all.

The proteins show up in two stages. The first consists of the spread of beta amyloid. The second results in tau protein. The initial amyloid may not pose a problem – plenty of people live with amyloid in their brains and don’t suffer memory problems. But when the tangles of tau appear, they destroy neurons. And that destroys your mental abilities.

According to researchers at Vanderbilt University, tau can spread through the brain like an infection, spreading from neuron to neuron, converting other proteins into messy tangles that can kill off neurons.

Some confirmation came when the Vanderbilt researchers used positron emission tomography (PET) scans to analyze how tau spreads through the brain. They found that the architecture of women’s brains makes the spread of tau go more easily and rapidly than it does in men’s brains.¹

Women’s brains, say the scientists, have more “bridging regions” that put them at greater risk of widespread neuronal damage.

Plus, there are other circumstances that put women’s brains at risk:

Research in Germany shows that middle-aged women are protected from brain problems by the estrogenic hormone called estradiol. But after menopause, the decline in this hormonal protection puts them at greater risk of Alzheimer’s and other brain problems.²
An analysis at UCLA shows that being a stay-at-home mom increases your risk of Alzheimer’s later in life. And being a single mother further increases the risk.³

Wait a Minute Here

However, both these observations look dubious to me. Men don’t have high levels of estradiol, so if this is a crucial factor, what’s protecting them? We need to know more. (It is true that hormone levels matter to brain health, in both sexes.)

As for stay-at-home and single mothers, there are so many sociological factors that relate to this, it would be nonsense to cite it as proof of a gender-related difference in your risk of dementia. For one thing – just a guess on my part – it could be that more educated women are less likely to be stay-at-home moms, and it’s well known that the well-educated and highly intelligent are less likely to get dementia.

Likewise it’s known that single moms have a whole raft of problems other women don’t have, and those problems are not on the XX chromosome.

There are many, many factors at work here.

And getting back to those stats about how two-thirds of Alzheimer’s patients are women and an elderly woman is more likely to get the disease than a male of the same age – again, we don’t know enough to jump to conclusions.

Men die younger for a variety of reasons, from heart disease to suicide to substance abuse. It could be that these other causes of death simply eliminate the men with dementia risk from the pool of possible dementia victims.

We don’t know enough. But the main discovery I mentioned above does after all point to a role for plaques and tangles, and if this turns out to be a distinct form of dementia, it appears women are more at risk of it.

Anyway women and men alike should take steps to prevent dementia. . .

Shrink the Risk of Alzheimer’s

One of the most important measures is to keep your weight down. Research shows that fat around the belly increases the danger of developing Alzheimer’s.⁴ And the scientists in Germany who examined how menopausal reductions in estradiol threaten a woman’s brain also noted that visceral fat around the waist does the same thing.

Eat plenty of fruits and vegetables. A study in Ireland (along with plenty of other research) shows these foods help preserve your cognitive health.⁵

Plus – here’s my broken-record speech: Get plenty of sleep⁶ and daily exercise⁷ to keep your brain in good shape. All of these lifestyle factors boost your odds of keeping your wits about you.