What the study reveals about menopause and immunity
A new study led by researchers at Queen Mary University of London suggests that hormone replacement therapy (HRT) could help reverse immune changes linked to menopause. The findings, published in Aging Cell, indicate that menopause significantly alters women’s immune profiles by increasing inflammatory monocytes and diminishing the body’s ability to clear infections. This research adds a crucial layer to our understanding of how ageing and sex differences shape immune health across the lifespan.
Monocytes: the immune system’s frontline cells
Monocytes are a type of white blood cell that act as first responders during infections. The study compared blood samples from younger adults (under 40) with those of older adults (65 and above). After menopause, women showed a shift toward more inflammatory monocytes, which are less efficient at clearing bacteria. This change helps explain why postmenopausal women may be more vulnerable to infections compared with men of the same age, whose immune profiles did not show the same shifts.
The role of complement C3
The researchers linked the altered monocyte landscape to lower levels of complement C3, a key immune protein that assists monocytes in engulfing and destroying microbes. In postmenopausal women, reduced C3 levels correlated with diminished infection-fighting capacity. By contrast, men did not exhibit this decline, underscoring a potential menopause-specific disruption of female immunity.
HRT appears to restore immune health
To investigate whether hormone therapy could influence this trajectory, the team studied peri- and post-menopausal women undergoing HRT. Those on hormone therapy demonstrated a healthier immune profile: fewer inflammatory monocytes, improved monocyte function, and higher levels of complement C3 compared with age-matched controls. Importantly, their immune markers approached those observed in younger women, suggesting that HRT may help maintain immune vigor beyond its traditional role in managing menopausal symptoms.
Implications for women’s health and policy
The study positions menopause as a critical turning point for immune health, with hormone loss accelerating immune decline in women. The potential for HRT to mitigate this decline offers an encouraging avenue for protecting older women from infections. However, experts warn that more research is needed to confirm whether these immune improvements translate into lower real-world infection rates and to determine how different HRT formulations or delivery methods influence the immune response.
What this means for clinicians and patients
While HRT is already commonly prescribed to relieve menopausal symptoms, these findings raise the prospect of broader benefits. Clinicians may consider immune health as part of a holistic discussion about HRT, particularly for women at higher risk of infections. Still, decisions about HRT must balance benefits and risks on an individual basis, with the authors stressing that routine HRT use solely for immune enhancement should not be assumed without further evidence.
Next steps in research
The researchers emphasize the need for larger, longitudinal studies to determine if HRT reduces concrete infection rates in the real world. They also aim to explore how different HRT formulations, doses, and routes of administration affect immune parameters. This work could eventually guide personalized treatment strategies that optimize both menopausal symptom relief and immune resilience.
Funding for the study came from Barts Charity and the Vivensa Foundation, reflecting a collaborative effort to illuminate how menopause intersects with immune aging and what we can do to support women’s health across the lifespan.
