Early menopause raises Alzheimer’s risk in women — Study

Sodiq Ojuroungbe

Women who enter menopause early may stand a high risk of developing Alzheimer’s disease, a new study carried out by a team of researchers from Boston, United States, has found.

The study suggested that starting hormone replacement therapy after the first symptoms of menopause occur may better improve brain health and reduce heart disease as well as other medical issues linked to the medical condition.

According to the lead author of the study, an assistant professor of Neurology at Harvard Medical School and Massachusetts General Hospital, Boston, Rachel Buckley, PhD, hormone therapy is the most reliable way to ameliorate severe menopause symptoms, but in the last few decades, there has been a lack of clarity on how it affects the brain

The World Health Organisation defines Alzheimer’s disease as a progressive disease that destroys memory and other important mental functions.

The WHO also states that Alzheimer’s disease may contribute to 60–70 per cent of dementia cases.

The study, which was published in JAMA Neurology, a monthly peer-reviewed medical journal, explained that using positron emission tomography neuroimaging scans from 292 people, the researchers studied how the presence of two proteins involved in Alzheimer’s, beta-amyloid and tau, are linked to menopause and hormone therapy use.

The researchers examined data on 99 men and 193 post-menopausal women who had no history of cognitive impairment.

Their finding showed that women who went through menopause earlier had higher levels of tau and beta-amyloid protein in their brains, even after accounting for genetic risk factors for Alzheimer’s disease and known risk factors for early menopause, such as smoking and surgical removal of the ovaries.

During the research, it was discovered that Tau is more present in greater quantities in women compared to men.

The PET scan results also showed that women had greater levels of tau compared to men of the same age, especially in cases where they also had elevated beta-amyloid.

The research also suggested that women who went into menopause before age 40 or from age 40 to 45, and started hormone therapy more than five years after they started menopause had higher levels of tau in their brains.

The researchers found that people who started hormone therapy around the time they began menopause didn’t have an increased risk for developing tau proteins in the brain, suggesting that the menopause treatment may temper the risk of developing Alzheimer’s disease.

The researchers concluded that going into menopause at an earlier age and starting hormone therapy late after menopause has begun could contribute to how much tau a woman develops in her brain.

The lead author, Buckley, in a statement made available to Healthline, noted, “Hormone therapy is the most reliable way to ameliorate severe menopause symptoms, but over the last few decades, there has been a lack of clarity on how hormone therapy affects the brain.

“The idea that tau deposition may underlie the association between late hormone therapy intervention and Alzheimer’s was a huge finding, something that hadn’t been seen before.”

Head of Research at Alzheimer’s Research, United Kingdom, Dr. Sara Imarisio, however, disagreed with some of the findings from the study.

She said, “While we understand that news like this can seem concerning, this study doesn’t show that hormone therapy causes Alzheimer’s. The researchers didn’t look at whether the participants went on to develop symptoms of dementia and we can’t be sure of cause and effect in this kind of research.

“It’s important that people are empowered with evidence-based advice that allows them to make informed decisions about their health. But there’s a lot more to understand about how menopause and HRT influence dementia risk. We need to see larger studies and controlled clinical trials to better understand this complex area of research and make sense of conflicting findings that have emerged in recent years.

“Some past research has highlighted potential cognitive benefits of hormone therapy, while other studies point to an increased risk of memory and thinking problems. While this study contributes valuable new data to this topic, we still aren’t able to point to a definitive link between hormone therapy and Alzheimer’s or dementia.

“Hormone therapy provides important benefits to many women, helping to combat the symptoms that menopause can bring. Women who take, or are thinking of taking, hormone therapy should not be put off by these results, and anyone concerned about the effects of this treatment should speak to their doctor.”

Similarly, a Consultant Endocrinologist and Honorary Professor, Centre for Intelligent Healthcare, Coventry University, Prof. Annice Mukherjee said, “This cross-sectional study investigates potential biological mechanisms associated with high tau deposition in female individuals, and risk of Alzheimer’s disease, particularly in the setting of high beta amyloid.

“Female sex, earlier age at menopause and menopause hormone therapy use were associated with higher regional tau PET in individuals with elevated AB, compared with male sex, late age of menopause, and HT non-use. The study also found a late initiation of HT was associated with higher tau, PET compared with earlier initiation.

“The authors identified this excess risk to relate to late initiation rather than early initiation or overall use of hormone therapy.. Overall numbers in the subgroups were small.

“This cross-sectional study adds to the existing conflicting body of observational evidence around the impact of menopause and hormone therapy on Alzheimer’s risk, with overall pooled existing data suggesting a null effect of hormonal therapy. The need for larger, appropriately powered RCTs are reiterated. Inference around existing conflicting data need to be viewed with caution.”


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