Whether it is a superhero in "The Avengers" or a vampire in "Twilight", immortality and eternal youth have always been eye-catching topics, which represent the ultimate dream of mankind. Scientists have also spent decades trying to use the power of genomics and artificial intelligence to find a way to prevent or even reverse aging, and there has been a flash of hope in some rodent studies.
Statistics show that since 1850, the average life expectancy of human beings has increased by about 3 months per year, which has been extended from more than 40 years to more than 70 years of age today. But does this mean that we are delaying death?
Recently, in a new study published in Nature Communications, a large team of scientists from 14 countries led by Duke University compared 39 human and non-human primate (
https://www.creative-biolabs.com/nhp-biologicals/) data and provided the most comprehensive evidence to date that changes in mortality patterns in specific species are mainly driven by changes in mortality before adulthood. In other words, although more and more people are living longer, the trajectory of death of the old has not changed. This research shows that evolutionary biology trumps everything. So far, medical progress has not been able to overcome these biological limitations.
From this we know that the further substantial extension of human life span will depend on whether it is possible to slow down the speed of aging, or reduce the mortality rate in old age in other ways. Therefore, biological limitations are a core issue of health science.
For decades, the debate about how long humans can live has caused huge differences in the academic community, but there is a lack of research based on the comparison of the life span of multiple species and humans.
This research team filled this gap, which analyzed the birth and death patterns in the population data of 9 humans and 30 non-human species, and studied the relationship between life expectancy and lifespan equality to compare the mortality differences within and between species.
The researchers found that the death patterns of all primates are the same, and that biological factors, not environmental factors, ultimately control lifespan.
Statistics confirm that with the improvement of health and living conditions, the life expectancy of individuals is prolonged, leading to an extension of the life span of the entire population. However, with age, the sharp rise in mortality is evident in all species.
Researchers have found that the close relationship between life expectancy and lifespan equality is common in NHPs and humans. Because in most mammals, the risk of death is mainly concentrated early in life, is relatively low in adulthood, and then increases again after aging begins.
Could the higher life expectancy be due to the slower aging of individuals or the longer life span?rnData from NHPs show that the answer may be no. The main source of differences in the average age of death among different primate populations is infant, adolescent, and adolescent deaths. In other words, life expectancy and life equality are not determined by the speed of individual aging, but by the death of infants and young children due to causes unrelated to aging.
In humans, life equality is closely related to life expectancy that people with a longer life expectancy show death in the same age group, while people with a shorter life expectancy show death in a wider age group.
The results of the study support that the increase in human life expectancy is more likely to be a statistical result of improved survival in children and young people rather than delaying aging.
Using mathematical models, the researchers also found that small changes in the rate of aging will greatly change the relationship between life expectancy and lifespan equality. On the other hand, changes in the parameters representing early death resulted in changes very similar to those observed.
Can human beings slow down their aging rate?rnThe researchers concluded that the results of this study support the view that in the historical population with low life expectancy, the improvement of infant mortality rate and mortality rate irrespective of age have been the main contributors to the trend of increased life expectancy and equal life expectancy in the past few decades. These improvements are mainly the result of environmental impacts, including social, economic, and public health advancements. However, since the mid-20th century, the decline in the baseline level of adult mortality is likely to have played an increasingly important role in industrialized societies. As the research shows, the improvement of the environment is unlikely to translate into a sharp decline in the aging rate, nor can it substantially increase lifespan. It remains to be seen whether the future development of medicine can overcome the biological limitations we have identified by now and achieve the goals that evolution cannot achieve.
According to the corresponding author of the study, Professor Susan Alberts from Duke University's Department of Biology and Evolutionary Anthropology, "We cannot slow down our aging rate. What we can do is prevent premature death early in life."