Naissukupuolihormoni estrogen regulates the menstrual cycle and is essential for a woman’s development and reproduction.
In addition to gender characteristics and sexual behavior, estrogen affects many other things around our body.
For example, it protects against cardiovascular diseases and brittle bones, and participates in the temperature regulation of our brain.
When a woman enters menopause and estrogen production declines, the end of menstruation is just one of many changes.
The risk of cardiovascular diseases increases, as does the risk of bone fractures. Sometimes you sweat, sometimes you feel cold when the temperature regulation fluctuates. At the same time, sleep also often deteriorates, mood swings and memory seems to be stuttering.
New information is constantly accumulating about where estrogen plays its role.
Women have, for example more than 50 percent higher risk suffer from memory disease during their lifetime than men. The researchers are investigating whether the female sex hormone group of estrogens possibly has something to do with it.
Now Researchers at University College London (UCL) report that estrogen has a protective role in the development of memory disorders.
A relatively early onset of menstruation may reduce a woman’s risk of dementia, the group reports In The American Journal of Geriatric Psychiatry.
In addition, the timing of menopause after the age of 50 can be good for brain health.
UCL researchers calculate the length of time a woman is exposed to estrogen. In addition to fertile years, the duration of possible hormone replacement therapy is calculated.
Long, 38–42 years of exposure to estrogen reduced the risk of dementia by 28 percent. Women who ended estrogen exposure between ages 50 and 52 had a 24 percent lower risk of dementia than those who ended estrogen exposure at age 45 or earlier.
The team also calculated that women who started menstruating at age 15 or later had a 12 percent higher risk of memory disorders than those who started menarche at age 12 or earlier.
In addition, removal of the ovaries or uterus slightly increased the risk of dementia.
The results are based on data from the British Biobank, which includes 273,260 women. Information about fertile years, hormone replacement therapy and removal of the uterus or ovaries was obtained from the women themselves.
Similar ones results has been obtained before too. However, the screen is not uniform, but in part studies estrogen shows to increase risk of memory disorders.
There have also been mixed results regarding the connection between hormone replacement therapy and dementia.
Why the display is so contradictory?
There are many confounding factors in studies of large datasets, says the professor of gynecology and obstetrics and senior physician Tomi Mikkola. A recent study also investigates the connection between estrogen and dementia, not a causal relationship, and the observed connection can be influenced by many things.
Uncertainty is also created by the fact that information such as the age at which menstruation began is based on the memories of the participants, and is often unreliable decades later.
In addition, the study deals with memory disorders as one group. This is a significant shortcoming, as the mechanisms of onset of different dementias differ from each other.
Numerous studies have shown that estrogen protects the heart and blood vessels. The same applies to hormone therapy started in the early stages of menopause.
The risk assessment of hormone therapy is always individual.
Estrogen can possibly work in the same way with respect to vascular dementia, Mikkola estimates.
He is with his colleagues observedthat estrogen-based hormone therapy reduces the risk of death due to vascular dementia.
Instead, long-term hormone therapy seems to increase the likelihood of Alzheimer’s disease, Mikkola’s group reports in 2019 in the BMJ scientific journal.
“In Alzheimer’s disease, the mechanism is completely different than in vascular dementia. Based on our research, estrogen has no apparent protective effect on Alzheimer’s disease.”
Menstruation or you cannot choose the time when menopause starts. But many women struggling with menopausal symptoms wonder if it’s worth starting hormone therapy, because there are benefits and drawbacks.
Risk assessment is always individual, says Mikkola, who works at the Hus Group and the University of Helsinki.
“Hormonal treatment has a small effect of increasing the risk of breast cancer. The initiation is also associated with a small increase in the risk of venous thrombosis, and in very elderly women the risk of cerebral infarction is increased. But on the other hand, there are fewer heart events, bone fractures, intestinal cancers and diabetes.”
The risk of breast cancer can also be related. When will be followed for ten years, two groups of 1,000 women, some with hormone therapy and others without, 34 of the users of hormone therapy get breast cancer. For non-users, the number is 26.