Throughout the 19th and 20th centuries, life expectancy experienced a notable increase thanks to improvements in nutrition, medical advances and other factors that had a very positive impact on the quality of life. However, after nearly doubling during the 20th century, the pace of this growth has slowed considerably over the past three decades, according to a new study led by the University of Illinois (UIC) at Chicago.
Despite continued advances in medicine and public health, life expectancy at birth in the world’s oldest populations has only increased an average of six and a half years since 1990, according to the analysis. This increase is much smaller than what some scientists expected, who predicted that life expectancy would continue to increase rapidly in this century, reaching the point that the majority of people born today would exceed 100 years of life.
The article published in Nature Aging with the title ‘The unlikelihood of a radical extension of life in humans in the 21st century’, presents new evidence that humans are reaching a biological limit in terms of their longevity. The greatest advances in lifespan have already been made by fighting disease, said S. Jay Olshansky, professor at the UIC School of Public Health and lead author of the study. Now, the main obstacle to continuing to increase longevity are the effects of aging.
“The majority of older people living today do so thanks to the time that medicine has created,” said Olshansky, who is also a professor of epidemiology and biostatistics. “However, these medical patches are adding fewer years to life, although the pace of medical advances is rapid. “This suggests that the period of rapid increases in life expectancy is now over.”
Olshansky also warned that prolonging life through disease reduction could be detrimental if those extra years are unhealthy. “We must now focus on efforts that slow aging and extend healthy lifespans,” he added. This concept, known as healthspan in English, measures the years a person lives in good health, not just how many years they are alive.
Invest in geroscience and improve life in older ages
The analysis, conducted with researchers from the University of Hawaii, Harvard and UCLA, is the latest contribution to a three-decade debate about the possible limits of human longevity. In 1990, Olshansky published an article in the journal Science arguing that humans were close to reaching a ceiling in life expectancy, estimated at about 85 years, and that the greatest advances had already been made. Other experts predicted that medical and public health advances would continue to raise life expectancy throughout the 21st century.
Thirty-four years later, the results of the new study support the idea that the increase in life expectancy will continue to slow, as more people will be exposed to the harmful and immutable effects of aging. The study analyzed data from the eight longest-lived countries, plus Hong Kong and the United States, one of the few countries that has seen a decline in life expectancy during the period studied.
“Our result challenges the common belief that our species’ natural longevity potential is ahead of us – a lifespan beyond what we have today,” Olshansky said. “In reality, that potential is behind us, in a range of between 30 and 60 years. “We have shown that modern medicine is generating ever-smaller improvements in longevity, despite the dizzying pace of medical advances.”
While more people are likely to reach age 100 or older this century, those cases will remain exceptions that will not significantly affect average life expectancy, Olshansky added. This conclusion also challenges the assumptions of industries such as insurance and wealth management, which make calculations based on the idea that most people will live to be 100. “That is deeply misguided advice, since only a small percentage of the population will live that long in this century,” Olshansky said.
“There is much room for improvement: reducing risk factors, eliminating disparities and promoting healthier lifestyles, all of which can allow people to live longer and better”
Despite this, the finding does not rule out that medicine and science may continue to offer benefits. The study authors argue that there may be more potential in improving quality of life at older ages, rather than just extending life. They recommend more investment in geroscience, the field that studies the biology of aging and which could be the key to the next wave of improvements in health and longevity.
“This is like a glass ceiling, not a brick wall,” Olshansky said. “There is much room for improvement: reducing risk factors, eliminating disparities and promoting healthier lifestyles, all of which can allow people to live longer and better. “We can break this glass ceiling of health and longevity with geroscience and efforts to slow the effects of aging.”
Diego Ramiro, director of the Institute of Economics, Geography and Demography of the CSIC, believes that the study is of good quality and “shows the process of slowing growth in life expectancy experienced by many countries in recent years. In some cases, not only a slowdown, but also a fall, as in the case of the United States. Given the most optimistic vision of a continuous growth in life expectancy at birth, with growth at 0.3 months per year, the authors show that this process will not have that rhythm, and that the evidence shows that this rhythm has slowed down. ”, he declared to SMC Spain.
“It would have been desirable for them to delve deeper into the reasons behind these brakes on accelerated growth in life expectancy. More specifically, in the inequalities within the same society in differences in life expectancy by educational level or socioeconomic level that can cause life expectancy to grow at different rates in each population group,” he concludes.
