The onset of menopause may coincide with an abrupt physiological change in systems involving bones, liver, kidneys and metabolism.
Most studies on menopause, the phase that begins when menstruation is missing for 12 months straight, describe the period leading to the definitive disappearance of menstruation as a gradual transition that is part of the aging process, and which progressively reshapes female biology.
Of another note is a new work published on Nature Medicinewhich instead considers it a sharp and sudden “leap”, which involves not only hormonal balance, but also the health of bones, liver and kidneys, as well as fat metabolism.
Although the study is limited to the observation of a large amount of data, and is therefore not definitive, it demonstrates how little we still know about this important step for women’s health.
An obvious step
Scientists at the Weizmann Institute for Science in Israel have created a computational model capable of separating a person’s chronological age from their reproductive history, a discrepancy that has complicated large-scale studies of menopause in the past. They then used this model to analyze the menopause transition in two large cohorts of women, one in the United States and another in Israel, using in all data from more than 300 million laboratory tests performed on more than one million women.
According to the authors, in both groups of participants, abrupt physiological changes in all systems of the female body were observed before menopause and in the last phase of the period characterized by the menstrual cycle, but more evidently in those involving the bones, the functionality of the liver and kidneys and the metabolism of lipids in the blood.
These same discontinuities, the authors say, were not detected in male participants and were attenuated in women on hormone replacement therapy aimed at replacing the hormones that the ovaries no longer produce.
“The systems in which the most significant changes were observed (e.g. bone health or the liver) are very sensitive to estrogen, while the systems that showed no detectable changes have a much weaker known binding to estrogen,” he explained to Science Alert Australian physiologist Mia Schaumberg, who did not participate in the study.
Critics: no sudden decline
However, the results do not meet with uniformly favorable opinion in the scientific community. Some scientists believe that the idea of a sudden transition could convey the message of a potentially alarming transition characterized by physical decline, a decline that the study does not demonstrate.
Others point out that menopause is much more than a simple closure of the reproductive period: the most recent studies have, for example, demonstrated that the ovaries, once their reproductive functions have ceased, have a second life as an immune hub.
The study also offers another interesting insight: it finds that from 15 to 12 years before the end of menstruation, anti-Müllerian hormones (AMH) and estradiol, produced by the ovaries, show signs of decline, while 14 years before menopause, levels of the follicle-stimulating hormone FSH, produced by the pituitary gland (the endocrine gland at the base of the skull), increase.
“Systemic changes associated with menopause could be predicted on the basis of hormonal changes much earlier than previously thought,” concludes Schaumberg.
