Hormone Therapy May Slow Biological Aging in Older Women

Key Takeaways

• Women who go through menopause generally age faster biologically than chronologically due to decreased levels of the hormone estrogen.
• But a new study found that increasing estrogen levels with hormone replacement therapy (HRT) can slow the pace of accelerated aging.
• Women who start HRT after age 50 and stay on the medication for less than a decade seem to experience the biggest benefits.

Postmenopausal women who have used hormone replacement therapy may be biologically younger than their counterparts who have never used this treatment, a new study suggests.

Biological age focuses on how well your body functions instead of how old you are chronologically. The decline in the hormone estrogen that naturally occurs during menopause is one of many factors that can accelerate biological aging in women, making them older than their chronological years, says study coauthor Yufan Liu of Capital Medical University in Beijing.

"Since estrogen has protective effects on various body systems, a drop in estrogen levels during menopause would accelerate biological aging," Liu says.

The study suggests that hormone replacement therapy (HRT) could help put on the brakes, potentially slowing functional deterioration, preventing major diseases, and improving longevity, Li says.

Study Looked at More Than 100,000 Women

For the new study, researchers examined data on about 47,000 postmenopausal women who had used hormone replacement therapy (HRT) and roughly 70,000 who had not. Subjects were in their late fifties and early sixties, on average.

In general, the women in the study were biologically older than their chronological age. But overall, the discrepancy between chronological age and biological age was 0.17 years smaller for the women who used HRT than it was for the women who didn't, according to findings published in JAMA Network Open .

From a biological aging standpoint, the biggest benefits from HRT appeared in women who used this treatment for about four to eight years, the new study found. In this scenario, the discrepancy between chronological age and biological age was 0.25 years smaller for HRT users than for women who never received this therapy.

Benefits were also more pronounced for women who started HRT after age 50. For these women, the discrepancy between chronological and biological age was 0.32 years smaller for HRT users than for non-users.

Hormone Replacement Therapy Is Used to Ease Menopause Symptoms

Women go through menopause when they stop menstruating, usually in their forties or fifties. Reduced production of the hormones estrogen and progesterone in the years leading up to menopause and afterward can lead to a wide range of symptoms, including mood swings, joint pain, vaginal dryness, insomnia, memory problems, and hot flashes and night sweats (the last two sometimes referred to as vasomotor symptoms of menopause).

Hormone replacement therapy is recommended to ease these symptoms in women younger than 60 or within 10 years of menopause onset, according to the Menopause Society.

How HRT May Impact Biological Age

The study wasn't a controlled experiment designed to prove whether or how taking HRT might directly impact biological aging. However, there are some psychological and physiological changes that can occur when women use HRT that might explain this connection, says Douglas Vaughan, MD , a professor emeritus and director of the Potocsnak Longevity Institute at the Northwestern University Feinberg School of Medicine in Chicago.

"HRT affects metabolism, systemic inflammation, dietary habits, and preferences, even overall state of well-being and vigor," says Dr. Vaughan, who wasn't involved in the new study. "Changes in lifestyle and diet that occur secondary to taking HRT may also be partially responsible."

The study does have several limitations. HRT use was self-reported by participants, making it possible that people didn't accurately report when they started treatment or how long they used it. Researchers also lacked data on the exact dosage or type of HRT participants used, and only assessed lab test results showing markers of biological age at a single point in time.

Beyond this, there may be differences between HRT users and non-users that influenced the results, says JoAnn Manson, MD, DrPH , a professor at Harvard Medical School and chief of preventive medicine at Brigham and Women's Hospital in Boston.

"Women who use hormone therapy are often healthier than non-users of hormone therapy, have fewer chronic diseases and comorbidities, healthier lifestyle practices, better access to healthcare, and higher socioeconomic status," says Dr. Manson, who wasn't involved in the new study.

More research is needed before drawing any broad conclusions about the effects of HRT on biological aging, Manson says.

Even so, the results add to the evidence suggesting that there may be an optimal window for starting HRT, Liu says. And the ideal timing for biological aging appears to be in line with current recommendations around when to initiate HRT and how long to continue treatment.

That's because women got the best results from a biological aging standpoint when they started HRT after 50 and stayed on it for less than a decade.

"From the perspective of aging delay, there is indeed optimal possible timing for hormone therapy use," Liu says.

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Sources

1. Liu Y et al. Hormone Therapy and Biological Aging in Postmenopausal Women. JAMA Network Open . August 29, 2024.
2. The 2022 Hormone Therapy Position Statement of The North American Menopause Society. Menopause . May 2022.

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Lisa Rapaport

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Lisa Rapaport is a journalist with more than 20 years of experience on the health beat as a writer and editor. She holds a master's degree from the UC Berkeley Graduate School of Journalism and spent a year as a Knight-Wallace journalism fellow at the University of Michigan. Her work has appeared in dozens of local and national media outlets, including Reuters, Bloomberg, WNYC, The Washington Post, Los Angeles Times , Scientific American , San Jose Mercury News , Oakland Tribune , Huffington Post, Yahoo! News, The Sacramento Bee , and The Buffalo News . See full bio See Our Editorial Policy Meet Our Health Expert Network