Menopause and Alzheimer’s… If declining estrogen is a factor, can Hormone Replacement Therapy protect menopausal women from dementia?
By Dona Suri
Alzheimer’s Disease is a type of dementia. It shows up as an impaired ability to remember, think, or make decisions; it interferes with doing everyday activities and is the most common type of dementia. It starts around age 50 with changes in the brain that are too faint to produce clinical symptoms. The person is thinking clearly but Alzheimer’s is already in the head. Twenty years later, the brain is sufficiently overwhelmed and people develop symptoms. Between onset of changes in the brain and onset of clinical symptoms lies a 20-year gap.
Doctors link the development of Alzheimer’s to a combination of genes, environment and lifestyle factors. Clinically speaking, what happens is an abnormal build-up of proteins in and around brain cells. One of the proteins is called amyloid and this protein forms plaques around brain cells. The other protein is called tau; tau deposits form tangles within brain cells.
The incidence rises steeply as people get older: You cannot say that age causes Alzheimer’s but the condition is certainly age-related.
Out of America’s total population in the age group 75 to 84, 13.1 percent will suffer from Alzheimer’s. After age 85, incidence goes up to 33 percent.
Is it possible to slow down this long decline? The Centers for Disease Control think so and, as usual, the factors to control are weight, blood sugar and depression.
Risk factors for Alzheimer’s are:
Number One: Aging
Number Two: Female sex.
Women have something men don’t – estrogen. Except that sometime between the ages of 45 and 50, a woman’s ovaries stop making estrogen and progesterone. It’s right around the time that women hit menopause that the amyloid plaque and tau tangles start. Coincidence?
Look at the statistics and a strange feature of the disease becomes apparent. Big difference in numbers for men and women! Twice as many women are Alzheimer’s patients. Why are women so vulnerable? Other neurological diseases don’t target women particularly. For example, men are much more likely to suffer from Parkinson’s. Vascular dementia strikes men and women in just about equal percentages.
Estrogen is not just one thing. The most potent and most abundant form of estrogen is called estradiol. Estradiol is crucially involved in reproductive processes… but that‘s not all. It also affects …
Neurons: it promotes their growth and repair
Neurotransmitters: (serotonin, dopamine, glutamate, and acetylcholine) it plays a role in regulating appetite, the sleep-wake cycle, and mood. It appears to have an antidepressant effect and influences the response to antidepressant medication.
Cognitive functions: it influences spatial reasoning, verbal ability and memory. It is also involved in fine motor skills.
Bone growth and maturation: bones respond to estradiol. It regulates production and replacement of bone cells in adults.
Cardio-vascular health: it helps to regulate High-Density Lipoprotein (good cholesterol) and Low-Density Lipoprotein (bad cholesterol).
Knowing how estrogen positively impacts overall well-being, emotional stability and cognitive function, you would think that doctors would not hesitate to prescribe estrogen replacement therapy for women aged 50+ but that is not so. Years of research have shown conflicting data on hormone therapy. Doctors want more evidence and indisputable evidence before they recommend estrogen replacement … particularly when the aim is to ward off Alzheimer’s.
The main reason why such evidence has not yet been provided is that a definitive study would have to follow a large group of women over a period of at least 40 years. Menopause occurs in the early 50s but Alzheimer’s doesn’t show up until a woman is in her 70s or 80s.
Advances in brain imaging are providing researchers with a way around this problem. They have made it possible to detect biological indicators of Alzheimer’s even in mid-life.
Previous clinical trials that investigated the role of hormone replacement therapy have not found that estrogen keeps the symptoms of Alzheimer’s at bay … but then these trials have all studied women above age 65.
Trials studying effects of hormone therapy on women in their 50s and 60s may tell a different story.
Work in this direction is already well under way. In its October 23, 2023 issue, academic journal Frontiers in Aging Neuroscience published Systematic Review and Meta-Analysis of the Effects of Menopause Hormone Therapy on Risk of Alzheimer’s Disease and Dementia. This was the report of a study that compared data from the 51 prior studies on estrogen therapy in mid-life and similar studies of much older women. The data included six randomized control trials and 45 observational reports, accounting for the experiences of more than 6 million women. The study (funded by the National Institutes of Health) was the work of a team of neuroscientists at Weill Cornell Medical College led by Dr Lisa Mosconi.
The analysis showed that estrogen (NOT estrogen plus progesterone) given to women in mid-life resulted in a 32 percent lower rate of dementia. The dementia rate did not change when estrogen was given to women in late life.
Dr Mosconi believes that starting estrogen replacement in midlife will prevent or delay the onset of Alzheimer’s but she concedes that the just-concluded study is still not conclusive and more research is needed. Indeed, the team has already launched into the next phase. This will be a clinical trial to investigate the safety and effect of the phytoestrogenic supplement (PhytoSERM) on regional brain metabolism by fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG-PET) in peri- and postmenopausal women. The team is guessing that they will find a significant difference between the PhytoSERM group and placebo group in glucose brain metabolism
Watch this space. In a couple years we may be able to tell you if taking estrogen early in menopause does indeed cut dementia risk and if you can take it without triggering some other problem.
What should you do in the meantime?
Exercise
Eat healthy
Don’t vegetate
Get out and meet people
Keep learning
Don’t worry, be happy!