When it comes to Alzheimer's disease, women in the United States have much higher rates than men—of the 5.8 million Americans living with the disease, two-thirds of those are women. Although conventional wisdom might say these higher rates are due to women living longer than men, the latest research says there's much more at play here.
New findings were shared in the 2019 Alzheimer's Disease Facts & Figures Report, the annual statistical resource for United States data, which was presented at the Alzheimer's Association International Conference. The research identifies "specific biological and social reasons" why Alzheimer's is not the same in men and women, said Maria C. Carrillo, Ph.D., chief science officer of the association.
Alzheimer’s spreads faster in women. Researchers from Vanderbilt University Medical Center cited "an accelerated brain-wide tau spread in women," which could also influence the rate of cognitive decline. Tau, a hallmark of Alzheimer’s disease, is a type of amyloid brain protein that clumps or plaques together with tangled bundles of fibers as it forms, leading to brain cell death. The study found that women with mild cognitive impairment (MCI) had more complex networks of tau than men. Connectivity between the different brain regions in women is stronger than in men's, so tau has an easier time spreading throughout the female brain.
Women use brain glucose to compensate for brain deficit. At the University of California San Diego School of Medicine, scientists looked at the fact that women do better than men on verbal memory tests, even if women have more amyloid build-up (one of the hallmarks of early Alzheimer's disease).
The researchers compared glucose metabolism in men and women with Alzheimer's, and whether differences noted may give women a verbal memory advantage. The metabolism or breaking down of glucose is how all cells in the body—especially those in the brain--get energy and function. Women exhibited more brain glucose metabolism at those minimal-to-moderate levels of amyloid deposition, even if they had early-stage Alzheimer's—but not so with severe deposits of amyloid or later-state disease.
So, what does this mean? Women may compensate for early-stage brain changes by maintaining brain metabolic function, and so may have stronger verbal memory.
Employed women may have a slower memory decline than unemployed women. Findings from the UCLA Fielding School of Public Health suggest that women who worked for pay between 1935 and 1956 may have higher levels of cognitive stimulation and more cognitive reserve. Verbal memory tests can indicate mild cognitive impairment in women when the disease has progressed.
Genetic risk factors differ in men than women. Researchers at the University of Miami named genetics as a contributor to differences in risk and disease progression in the two genders. While there is still plenty of follow-up research that needs to be done, they found that of the 11 different sex-specific genes that predispose men and women to Alzheimer’s disease, there are some that only raise the risk in men and some that only raise the risk in women.
Alzheimer's Disease Risk Factors
The 2019 Alzheimer's Disease Facts and Figures report reminds us that Alzheimer's is a degenerative disease that occurs when nerve cells or neurons involved in thinking, learning, and memory are damaged or destroyed. A healthy adult brain has approximately 100 billion neurons. The report said that in most cases Alzheimer's develops due to multiple risk factors that include the following, some controllable, and some not:
- Age: Most people who develop it are over 65.
- APOE or apolipoprotein E: Everyone inherits one of three forms: e2, e3, or e4, from each parent. Those who carry the e4 form are at greatest risk.
- Family history: Having a parent, brother or sister with Alzheimer’s makes a person more likely to develop it than if they don't have a first-degree relative with the disease.
Help Lower Alzheimer's Disease Risk
There are no guarantees when it comes to preventing Alzheimer's, but previous research says these tactics may help reduce risk.
Manage cardiovascular risk factors. These include diabetes, obesity, smoking, hypertension or high blood pressure.
Eat a healthy diet. Go for fruits, vegetables, whole grains, fish, chicken, nuts and legumes, and limit saturated fats, red meat and sugar. To keep it simple, use eating plans from the DASH (Dietary Approaches to Stop Hypertension) diet, and the Mediterranean diet.
Move it. Stay active and keep moving with all forms of regular physical exercise.
Keep learning. People with more years of formal education are at lower risk.
Reach out. Stay socially connected and mentally active and engaged.
Take care. Protect your brain from head trauma, specifically traumatic brain injury. Accidents do happen, of course, but wearing appropriate headgear in certain sports, always wearing your seat belt, and doing a potential "fall assessment" survey at home goes far to help prevent brain injury.