Menopause not gradual, body might experience a 'physiological cliff' around last period: Study

Menopause may not be a gradual process taking years as is commonly thought -- instead, the female body could be traversing a "physiological cliff" around the time of the last menstrual period, a new study has found.

Analysing more than 300 million laboratory test results from over one million women in the US and Israel, researchers at Weizmann Institute of Science identified abrupt changes in dozens of measures of bodily health and function, far beyond the familiar shifts in sex hormone levels and the loss of fertility.

Findings published in the Nature Medicine journal showed that the changes appeared in 52 of the 90 types of laboratory tests examined, covering nearly all body systems, including tests of bone health, liver and kidney function, and cholesterol levels.

The changes were found to be less pronounced among women receiving menopausal hormone therapy.

Further, the sudden shifts were preceded by accelerating changes in sex hormone levels that began more than a decade before menopause -- several years earlier than previously thought.

None of the abrupt changes were observed in men of similar ages, the study found.

It "revealed a step-like physiological cliff at the FMP (final menstrual period) including endocrine, skeletal, hepatic, renal and lipid systems," the authors wrote.

Because most of the abrupt changes identified in the study are associated with increased disease risk, the findings could help women take preventive steps, such as exercising and improving their diet, years before menopause, the researchers said.

"Our study extends the window for potential preventive care to almost a decade before menopause. More broadly, the method we developed may help study other major changes in life, such as puberty, pregnancy or the onset of disease," author Uri Alon, from Weizmann Institute of Science, said.

Two sets of data were analysed -- results from the US National Health and Nutrition Examination Survey, conducted over more than two decades, and medical records collected over around 20 years by Israel's health insurer Clalit.

The researchers said that such large datasets are rarely used in menopause research because they generally lack information about the age at which women had their last period.

To overcome the limitation, the team developed a computational method which they said is inspired by astronomy.

Just as astronomers can sharpen an image by mathematically correcting distortions caused by a telescope, the new method removed the 'blur' in medical data caused by differences in the age at which women reach menopause, the researchers said.