Women鈥檚 cells show the hallmark signs of ageing in early adulthood, whereas this tends to only occur in men from age 40, according to new research.
at the University of Copenhagen鈥檚 Center for Healthy Aging and his colleagues used machine learning to analyse 33 million biopsy reports taken from more than 4.9 million individuals, ranging from newborn babies to people who were more than 100 years old, between 1970 and 2018. Transgender people weren鈥檛 included in the study.
After identifying markers of ageing, such as inflammation or the formation of giant cells, the researchers attempted to uncover whether the onset of this differs between the sexes.
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They found that while cellular ageing didn鈥檛 appear to start in the men until age 40, on average, it then happened very rapidly. In contrast, the first signs of ageing in the women seemed to begin at around age 19, but then progressed gradually.
This might explain why women are generally more at risk of certain health complications, says Ben Ezra. 鈥淔or example, women have higher levels of frailty throughout life, so that would fit with ageing beginning earlier in females.鈥�
However, the biopsies were only taken when the participants sought medical attention. Male ageing may therefore appear to begin later, as men tend to seek medical help when their symptoms are more advanced than their female counterparts, says study co-author , also at the University of Copenhagen.
The researchers didn鈥檛 account for how advanced the participants鈥� health issues were when they sought medical attention, but Scheibye-Knudsen says that signs of cellular ageing could potentially have been picked up in biopsies when the male participants were younger if they had seen a doctor earlier.
at the University of Essex, UK, says that substantial differences in biological ageing have been identified between the sexes before. It has previously been suggested that , and the effects of age-related inflammation on blood and other tissues are more substantial in older men than in women of the same age.
Rallis also notes, however, that the samples in Ben Ezra and his team鈥檚 study were taken from people in some state of ill health, with certain medical conditions potentially having a greater impact on cellular ageing than others.
鈥淭hey are looking at [different] disease pathologies and the timing of them becoming apparent in men and women, so it is quite tricky to directly relate [the results] to the ageing process itself,鈥� he says.
Ideally, this study would have been carried out using biopsies from a range of participants of different ages with no known health issues, says Rallis.
The biopsies were also only collected from white people and therefore the results may not apply to people of other ethnicities, says Ben Ezra.
Nevertheless, the results also suggest that tissues in the liver age in a relatively slow and predictable way, whereas tissues in the heart age in a more erratic pattern, regardless of whether the biopsy was taken from a man or woman.
This could help us better understand at what age a person is most at risk of different medical conditions that affect specific organs, says Scheibye-Knudsen.
With more research, the study鈥檚 database of biopsy reports could be combined with an artificial intelligence to create a system that receives biopsy reports from a doctor and then predicts that person鈥檚 risk of different medical conditions according to their age, says Ben Ezra.
bioRxiv
