In the case of Alzheimer’s Disease (AD), the James Brown song is correct–this is a man’s world. Women are drastically more affected by the disease and its devastating effects, with over 60 percent of Americans currently diagnosed with AD being female. AD risk for women in their 60’s is double that of breast cancer. Women are also disproportionately the caregivers of those affected by AD, again totaling over 60% of care partners.
The difference in the prevalence in Alzheimer’s Disease has been primarily attributed to women’s overall greater longevity for many years, given that age is the first and foremost indicator of risk for the disease. Only recently has the medical field begun to delve into these gender differences, and findings reveal that gender differences in prevalence rates of AD are a far more complex interaction of genetics and biology and life experiences or environment.
Genetics and Biology
The interaction between genetics and biology and environment and experiences which combine to create the perfect storm for AD is a complex and nuanced one.
Research shows that the women who carry ApoE4 gene (which contributes to both Alzheimer’s Disease and Cardiovascular Disease) are more than 2x as likely to develop AD as those without the gene. Not only does ApoE4 increases the risk for AD, it also increases the severity of the disease over its course. Risk for AD in men with the ApoE4 gene increases as well, but only slightly. Research is beginning to indicate that the mediating and moderating factor in the different implications of the ApoE4 gene among the sexes may be estrogen.
Research demonstrates that after menopause, in women aged 65-79, the risk for heart disease increases, and almost half of menopausal women report noticeable signs and symptoms of cognitive decline. Women have more white matter in the brain proportionally to men and some researchers hypothesize that this increased white matter in female brain may make this sex more susceptible to AD. Additionally, women’s brains appear to be more susceptible to the accumulation of amyloid plaques, a key component of AD (Brain Longevity Therapy Training Curriculum 2018). Recent studies indicate that tau networks in women with mild impairment were more diffuse and spread out than in their male counterparts, which suggests that the effect was more severe in women (Associated Press, 2019).
Further evaluation revealed that women with more severe symptoms of menopause had the weakest functional connectivity in the brain, while women with highest estradiol (an estrogen-based hormone medication) levels showed better memory performance. Women who have had a hysterectomy in which the ovaries were removed before menopause also show a 140% increase in AD risk. All of this information indicates that estrogen plays a mediating and moderating role on cognition and the development of AD, and that biological makeup may interact with genetics in contributing to AD (Brain Longevity Therapy Training Curriculum 2018).
Heart Health and Brain Health
Research shows that the complex interaction which results in AD may also involve women’s social role and the repercussions that role has on brain and heart health. As I mentioned before, post-menopausal women are at an increased risk for cardiovascular disease, and cognitive decline. Indeed, Alzheimer’s Disease and Cardiovascular Disease share a number of risk factors, including obesity, depression, diabetes, high cholesterol, and research shows that heart health inextricably connected with brain health. Reduced or irregular blood flow to the brain is one of the mediators between this head-heart relationship, but so is grief.
One terrible aspect of women’s greater longevity is that it means women often outlive spouses and loved ones. This can and does result in high levels of grief, depression, and bereavement which take a physical and psychological toll on women left without their loved ones, and doubles their risk for AD. Women living alone or with a disabled spouse, or even with disability themselves have higher levels of stress and anxiety, which research indicates also play a role in increasing AD in women (Brain Longevity Therapy Training Curriculum 2018).
Social support is an important factor in protecting against AD, and women in their old age are often either left without this support or are relied on for it by others. Women also carry the majority of the burden of caring for others within society and family structures. Women are more likely to be care partners to friends or family with dementia, a role which often increases stress. Overall, there are 2.5 times more women than men who live with a person with dementia full-time.
Over one-third of dementia caregivers are daughters, which is an important statistic given the interaction between the potential stress of caregiving with genetic inheritance. The disease has a long course which given contributing factors, can cause AD to begin to develop as early as one’s 20’s and 30’s.
Additionally, women caregivers often experience higher levels of depression and impaired health than male caregivers, likely due to the fact that female caregivers tend to spend more time caregiving, to take on more caregiving tasks, and to care for an individual with more severe disease and disability (The Alzheimer’s Association, 2019). Women’s social role, which increases their likelihood of acting as a caregiver for someone who has AD with whom they are genetically related, coupled with lack of social support may put women uniquely at risk.
Women lack another protective factor which may be related to the glass ceiling. Higher levels of education and lifelong learning have been linked to decreased rates of AD. This is attributed to increased cognitive stimulation and cognitive reserve, or the behavioral measure of the brains resistance to damage (Brain Longevity Therapy Training Curriculum 2018). However men historically have been more likely to achieve a higher level of education. This trend has only just recently begun to tip the other way and the cognitive effects of this disparity in the mentally protective factor of education are still measurable in the living population.
Because the disease course is so long and because Alzheimer’s begins to develop in early adulthood, early diagnosis is crucial to effective management and prevention. While women are far more likely to have Alzheimer’s than men, it is suspected that they are also far more likely to go undiagnosed. Women do better than men on measures of verbal ability, which masks the damage done by the disease. Women’s ability to outperform men in verbal memory tests used to evaluate cognitive function, such as recalling words and lists, also contribute to under-diagnosis of AD in women.Research has revealed that women did better than men on tests of verbal skills, despite similar signs of early to moderate Alzheimer’s. Further research revealed that this may have to do with differences in the rates at which the women metabolize glucose, which the brain uses for fuel. “The female advantage might mask early signs of Alzheimer’s and delay diagnosis,” said study leader Erin Sundermann. “Women are able to sustain normal verbal performance longer,” partly because of better brain metabolism. (Associated Press, 2019).
One researcher reflected, “If women are inaccurately identified as having no problems with memory and thinking skills when they actually have mild cognitive impairment, then treatments are not being started and they and their families are not planning ahead for their care or their financial or legal situations” (Miller, 2019). Not only does this reflection demonstrates the current hidden risk that AD has on the lives of women, it also emphasizes the need for more support, care, and diagnosis resources.
So how do we begin to turn the tides of the extreme gender gap in Alzheimer’s Disease? James Brown also told us the answer by acknowledging that the world wouldn’t mean nothing without a woman or a girl. A great place to begin doing so is by spreading awareness, by caring for our women, by encouraging healthy life habits for women, by reducing the burden of care on women. One can do so by supporting public policies which broaden public care, insurance coverage, and which increase services for individuals with AD and their care providers. Another important way to acknowledge women’s greater suffering when it comes to AD and to support change is by investing in further research into gender differences in the development of AD. But the very first and foremost step, is in supporting the women around you, not only in caring for others, but caring for themselves.
Brain Longevity Therapy Training Curriculum (2018). Alzheimer’s Research and Prevention Foundation. www.alzheimersprevention.org
Associated Press. (2019). New clues on why women’s Alzheimer’s risk differs from men’s. STAT.https://www.statnews.com/2019/07/16/new-clues-women-alzheimers-risk-differs-from-men/
The Alzheimer’s Association. (2019). Women and Alzheimer’s. The Alzheimer’s Association