Dementia is becoming more concerning as people live longer lives.
Since there’s currently no cure for dementia, experts are exploring various factors that may influence the risk of developing it. One area of interest is the role of estrogen, a hormone, and its levels in women’s dementia risk.
A recent study published in The American Journal of Geriatric Psychiatry investigated specific reproductive traits and how they relate to dementia risk.
The researchers discovered that individuals with longer exposure to estrogen had a lower risk of dementia. Estrogen exposure was measured by the number of years between the onset of menstruation and menopause, or the occurrence of a hysterectomy or oophorectomy.
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Conversely, those with shorter estrogen exposure faced a higher risk of dementia. This included participants who started menstruating later in life.
The study authors concluded that estrogen might serve as a protective factor against dementia, but further research is necessary in this area.
Despite the fact that this study demonstrated the preventive benefits of lifetime estrogen exposure, human study outcomes are inconsistent. Future multidisciplinary cohort studies ought to ascertain how estrogens affect dementia risk.
What Health effects do Estrogen levels have?
Estrogen is a hormone crucial for the female reproductive system. It’s responsible for breast development, changes in the uterine lining, and preventing vaginal dryness. But its effects extend beyond reproduction.
“Estrogen affects various systems in the body including the skin, heart, blood vessels, hair, pelvic muscles, brain, mucous membranes, and urinary system,” explained Dr. Kecia Gaither, an OB-GYN and maternal-fetal medicine specialist at NYC Health + Hospitals/Lincoln.
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After menopause, estrogen levels drop, marked by a year of no menstruation. This decline in estrogen may increase the risk of conditions like osteoporosis and heart disease.
Dr. Michael Krychman, an OB-GYN and medical director at MemorialCare Saddleback Medical Center, clarified this point.
“When a woman reaches menopause and her estradiol and testosterone levels drop, it can cause a range of symptoms. These include hot flashes, vaginal dryness, painful intercourse, and decreased libido. Without enough estrogen, women may experience faster bone loss, leading to conditions like osteopenia or osteoporosis. Other symptoms may include weight gain, mood swings, and fatigue. Hormonal changes can also affect appetite, sleep, and energy levels.”
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How does Estrogen affect the likelihood of dementia?
The researchers in this study aimed to investigate how estrogen affects the risk of dementia and whether the duration of estrogen exposure plays a role in this risk.
They examined data from 273,260 participants in the UK Biobank, all of whom identified as women and were free of dementia at the start of the study.
These participants provided information on various factors such as age at first menstruation, reproductive surgeries, age at menopause, and childbirth history.
The researchers defined the age of last estrogen exposure as the age of natural menopause, surgical removal of ovaries, or hysterectomy. For those who didn’t report these ages, it was estimated as the age at data collection minus one year.
If participants didn’t report natural menopause or surgery, it was assumed they had ongoing estrogen exposure. Additionally, participants indicated whether they had ever received hormone replacement therapy.
The researchers also considered other factors like family history of dementia, education level, body mass index (BMI), smoking, diabetes, and high blood pressure. Over the course of the study, 3,694 participants developed dementia.
Overall, the study found that longer estrogen exposure was linked to a lower risk of dementia. They found that participants with a later age of last estrogen exposure had a 24% lower risk of dementia.
However, those who experienced first menstruation at age 15 or older had a 12% higher risk of dementia, and those with a history of reproductive surgeries had an 8% higher risk.
Interestingly, the study didn’t find a significant association between hormone replacement therapy (HRT) and dementia risk. These findings suggest that estrogen may have a protective effect against dementia.
Further studies on the protective properties of estrogen are required
This research has some limitations to consider. The data used came from the U.K. Biobank, which may not represent all populations and could affect the generalization of the results. There’s also a possibility of inaccuracies in the participants’ reports. Another factor is that the study didn’t include the oldest age group, which might have influenced the findings.
Furthermore, there were missing data for some reproductive factors, and the number of women who experienced natural menopause was much higher than those who had surgeries, potentially affecting the results. Additionally, details about hormone replacement therapy were not available.
Dr. Park suggested another area for future research: “Exploring the effects of estrogen in individuals with early-onset and late-onset dementia could be valuable,” she said. “Understanding how estrogen’s protective effects might vary with time since menopause and interact with genetics like APOE genotype is important for future investigations.”
Despite these limitations, the study suggests that estrogen might have protective effects against dementia risk. However, more research is necessary before any significant changes are made to clinical practice.
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