Women who experienced the menopause transition before age 45 were more likely to develop dementia later in life than women who began natural menopause at the average age, according to new preliminary research.
“Our study found that women who enter menopause very early were at greater risk of developing dementia later in life,” said one author of the study, Wenting Hao, MD, a PhD candidate at Shandong University in Jinan, China, in a press release.
Being aware of this increased risk can help women practice strategies to prevent dementia and to work with their physicians to closely monitor their cognitive status as they age, said Dr. Hao.
The Average Age of Menopause in the U.S. Is 51 Years Old
Menopause is defined as no menstrual periods for 12 consecutive months, according to the North American Menopause Society (NAMS). On average, a woman reaches menopause at 51.
If you reach menopause before age 40, it’s considered premature menopause, says Stephanie S. Faubion, MD, the director of the Center for Women’s Health at the Mayo Clinic in Rochester, Minnesota, and the medical director of NAMS, who was not involved in this research. “That occurs in about 1 to 2 percent of women,” she says.
“Menopause at 40 to 45 years of age is called early menopause, and that occurs in about 5 to 7 percent of the population, so it’s safe to say that at least 7 percent of women are going to go through menopause early or prematurely,” says Dr. Faubion.
What Determines When a Woman Will Go Through Menopause?
There are many factors that play into when a woman will go through menopause, said Lauren Streicher, MD, a clinical professor of obstetrics and gynecology and the medical director of the Northwestern Center for Menopause in Chicago, in an earlier interview with Everyday Health.
“When we look at the things that are the greatest determinants for when someone is going to go through menopause, genetics seems to be one of the most important,” she said.
A woman’s race or ethnicity can influence when she goes through menopause, too, she says. Findings from the Study of Women’s Health Across the Nation (SWAN) indicate that women of color tend to begin perimenopause and menopause at earlier ages than white women.
Smokers and those who have certain medical conditions, such as autoimmune problems, thyroid issues, and lupus are all more likely to experience earlier menopause, said Dr. Streicher.
Early Menopause Linked to Early-Onset Dementia
To explore the potential relationship between age at menopause onset and the diagnosis of dementia from any cause, researchers used health data from 153,291 women who were an average age of 60 when they were enrolled in the UK Biobank (between 2006 and 2010).
The UK Biobank is an international health resource that collects blood, urine, and saliva samples along with detailed health information for research on a wide range of illnesses from over a half million people.
The investigators looked for any diagnosis of all types of dementia, including Alzheimer’s disease, vascular dementia and dementias from other causes. After controlling for factors including age at last exam, race, educational level, income, cigarette and alcohol use, BMI (body mass index), cardiovascular disease, diabetes, and leisure and physical activities, researchers calculated the risk of occurrence in relation to when the women went through menopause.
The analysis found:
- Women who went through the menopause transition before age 40 were 35 percent more likely to be diagnosed with dementia.
- Women who entered menopause before age 45 were 1.3 times more likely to be diagnosed with dementia before age 65 (called presenile or early-onset dementia).
- Women who went through menopause later — at age 52 or older — had similar rates of dementia to those women who entered menopause at the average age of 50 to 51 years old.
Researchers did not find an association between age at menopause and the risk of vascular dementia.
“These findings from the UK Biobank are consistent with other studies in showing a greater risk of dementia in women with premature or early menopause,” says Faubion.
A study published in March 2019 in Neurology found that women who started menstruation at a later age or who entered menopause early (in either case, women with a shorter-than-average reproductive window) had more than a 20 percent increased risk of developing dementia later in life.
The authors of that study proposed this added risk could be related to the women’s reduced exposure to estrogen during the reproductive years.
Hao, too, attributed the increased risk of dementia in her study to a lack of the hormone. “We know that the lack of estrogen over the long term enhances oxidative stress, which may increase brain aging and lead to cognitive impairment,” she said.
The early loss of estrogen is associated with an increased risk for multiple adverse long-term health outcomes; dementia is just one of them, notes Faubion. “That includes heart disease, osteoporosis and fracture, mood disorders, sexual dysfunction, and early death,” she says.
More Research on Menopause Timing and Dementia Is Needed
“Further research is needed to assess the added value of including the timing of menopause as a predictor in existing dementia models,” Hao said. “This may provide clinicians with a more accurate way to assess a woman’s risk for dementia.”
Faubion agrees there's a need to further investigate whether incorporating age at menopause enhances the ability to predict dementia risk.
“As stated by the authors, the lack of information on type of menopause — natural or related to removal of both ovaries — is a limitation,” says Faubion.
The data used for this study included mostly white women living in the U.K. and may not generalize to other populations.
Prevention Strategies to Reduce the Risk of Dementia
Healthcare clinicians who care for women should be aware of a woman’s age at menopause onset and closely monitor for cognitive decline in those who reached menopause before age 45, said Hao.
“In addition to the monitoring of these women, replacing estrogen is a key strategy and has been shown to mitigate dementia risk and other risks in women with premature or early menopause,” says Faubion.
There are some risks associated with taking hormones to replace estrogen (hormone replacement therapy or HRT), according to MedlinePlus. Talk with your healthcare provider to discuss your individual risks and benefits.
There are a number of ways women who experience early menopause may be able to reduce their risk of dementia, said Hao. “This includes routine exercise, participation in leisure and educational activities, not smoking and not drinking alcohol, maintaining a healthy weight, getting enough vitamin D and, if recommended by their physician, possibly taking calcium supplements,” she said.