Does Midlife Health Change Differently for Women and Men?

By the mid-40s or 50s, annual blood tests often begin to carry more weight. Cholesterol, glucose, blood pressure, body composition and cardiovascular risk start to sit alongside sleep, exercise and recovery as part of a broader preventive-health picture.

But should the same numbers always be interpreted in exactly the same way for women and men of the same chronological age?

A large study published in Nature Aging suggests the answer may be more complicated.

Researchers analysed 172 clinical measures from more than 100,000 adults aged 18 to 98 across three medical centres in China. Rather than assuming that ageing follows one uniform trajectory, they examined how multiple physiological markers changed across adulthood and whether those patterns differed by sex.

The clearest divergence appeared during midlife. Patterns in women and men became more similar again at older ages. Among the clinical measures that accumulated with age were familiar metabolic markers including LDL cholesterol, triglycerides, glucose and uric acid. The study also examined changes across several physiological systems rather than relying on a single blood test or one definition of ageing.

For someone interested in preventive health, this is perhaps more useful than the ageing clocks the researchers also created.

Chronological age tells us how many years someone has lived. It does not describe, on its own, what is happening to cardiovascular health, glucose regulation, kidney function or other systems. Those processes can change at different rates, and the new study suggests their age-related patterns may not be identical in women and men.

That also complicates the increasingly popular idea of reducing health to one “biological age” score. A person could have favourable markers in one area and less favourable ones elsewhere. A single number may be convenient, but it cannot represent every physiological system at once.

The study does have an important limitation. Its human data were cross-sectional: researchers compared people of different ages rather than following the same individuals from early adulthood into old age. The participants were also drawn from Chinese clinical cohorts, so the results should not automatically be assumed to apply identically to every population.

Nor does the research establish separate longevity programmes for women and men.

Its more practical message is simpler. Midlife health is multidimensional. Rather than asking only, “What is my biological age?”, it may be more useful to look at how individual markers are changing over time — and what those changes mean in the context of the person being tested.