The longevity revolution put on brakes: Most of those born today will not live beyond 100 years. health and wellbeing

Humanity has been challenging the odds of longevity for more than a century: the life expectancy of a child born in the early 19th century was about 30 years; Today, a child of the new millennium comfortably exceeds the age expectation of 80 in most developed countries. Medical and public health advances have destroyed all theoretical limits on life expectancy. In the 1920s, the maximum limit was estimated to be 64; Mid-century, which will be 73 for men and 79 for women. But the question of how long humans can survive is still up in the air.

The scientific community has debated in recent decades whether the longevity revolution that occurred with the rapid increase in life expectancy in the 20th century is coming to an end. So-called radical life extension: three more years added to each decade. Some scientists predicted in the 1990s that life expectancy growth would slow in the 21st century, but other schools of thought proposed that this hypothesis did not take into account advances in medicine and biology and even That predicted that most newborn babies would survive today. Being 100 years old or older. The discussion continues, but new research was published this Monday in the journal nature aging Provides reassurance that the radical increase in life expectancy experienced in the 20th century is slowing. The authors suggest that it is “unlikely” that more than 15% of women and 5% of men will be centenarians this century.

Scientists analyzed mortality data from the nine regions with the world’s highest life expectancy (Hong Kong, Japan, South Korea, Australia, France, Italy, Switzerland, Sweden and Spain) and the United States between 1990 and 2019 and reported that , Over these 30 years, the general improvement in life expectancy has slowed. “The longevity revolution is reaching its peak, just as we predicted when we first addressed this topic nearly 34 years ago,” said Jay Olshansky, a professor at the University of Illinois College of Public Health in Chicago, United States). . Author of the study. And he adds: “Although it is still possible to increase it by reducing diseases, the gains in longevity in Spain and other parts of the developed world will now be small. “That doesn’t mean we should stop trying to fight the disease, it just means that that investment will have fewer and fewer long-term benefits.”

This three-year expansion every decade will need to continue to maintain the longevity revolution that humanity has experienced over the past century. But the research showed that the only regions to experience this rapid growth since 1990 were South Korea and Hong Kong. In the rest of the population, “the annual increase in life expectancy has slowed to less than 0.2 years per year,” they explain in the scientific article. Furthermore, the United States is one of the few documented countries to have a lower life expectancy at birth at the end of any decade than at the beginning of the decade. The authors point out that this phenomenon also occurred in the first half of the 20th century, but was caused by extreme events such as war or epidemics.

Scientists assure that increasing life expectancy “has become increasingly more difficult” and the milestone of the majority of the population reaching 100 years of age, at the moment, seems unattainable. “There is no evidence to support the suggestion that most newborns today will live to be 100,” the authors insist. In fact, they found no population that came close to 50% survival to age 100: according to their 2019 mortality data, the highest probability of any population living to age 100 was found in Hong Kong, Where they expect. , that 12.84% of women and 4.4% of men become centenarians.

The largely uncertain milestone of reaching 100 years of age

“It would be optimistic that 15% of women and 5% of men in any human birth cohort could live to age 100 in most countries this century.” Theoretically, that limit could be overcome if treatments were developed that would slow human aging. But still, they warn, “surviving to age 100 is not certain for most people.” For now, the authors illustrate, efforts by the United States National Institute on Aging’s Intervention Testing Program to find potential treatments to delay aging have “limited effectiveness”: only 12 of the 50 compounds examined Has increased life expectancy, but not by more than 15%.

Olshansky and his team’s analysis showed that for a second wave of radical life extension to push life expectancy at birth to 110 years in the future, “70% of women would need to live to 100”. Or put another way: To reach the life expectancy limit of 110 years at birth, about one in four women would have to live to be 122, which is the maximum life expectancy observed in humans. French woman Jeanne Calment, considered the dean of humanity, died at the same age in 1997. They explain, “To radically extend lifespan, about 6% of women would need to live to age 150, 28 years longer than the oldest documented human in history.”

Olshansky acknowledges that “it is entirely possible” that increases in life expectancy will stop altogether. However he says there is still room for continued improvement. “All countries have the potential to further increase this, not only by reducing disparities between population subgroups, but also by modifying risk factors, such as reducing obesity and smoking,” he explains via email. According to their analysis, life expectancy at birth as of 2019 is 88.68 years for females and 83.17 years for males. However, other research in 2019 projected a potentially higher life expectancy by 2039: 91.6 years for women and 86.1 years for men.

Optimism and biological limits

The authors of this study reject pessimistic interpretations of their findings and argue that “humanity’s fight for longer lives has already been largely achieved.” “This is not a pessimistic view that the longevity game is over or that it is no longer possible to continue improving mortality rates at all ages (especially at older ages); Or that it is no longer possible to improve life expectancy by modifying risk factors or reducing survival disparities. “Rather, it is a celebration of more than a century of public health and medicine that has allowed humanity to gain ground on the causes of death that, until now, limited human longevity,” they concluded in the article. .

Although their evidence indicates that “human life expectancy has ended because of the first longevity revolution,” the authors say there is room for optimism and that “a second longevity revolution may be imminent as modern efforts to slow biological aging which will offer humanity a second chance to change the direction of human existence.” But when this scenario does not materialize, the authors return to the data of their analysis and assure that it is “unlikely” that there will be a radical expansion of life in these studied regions in this century.

Ramón y Cajal researcher Mercedes Sotos Prieto at the Complutense University of Madrid and the Networked Biomedical Research Center for Epidemiology and Public Health assures that this study, in which she has not participated, “provides evidence about the slowdown in improvements in life expectancy. Does.” ”, but cautioned that it would not necessarily settle the scientific debate about what its limits are. “Although it seems we have reached a certain limit, the debate may continue as new advances and discoveries emerge,” he says.

Demographer Rosa Gómez Redondo, a university professor and member of the Human Mortality Database and Longevity Database, agrees on this point: More than settling the debate, this study “provides new data, deferring to previously proposed predictions. ” “Each new generation presents new characteristics in its demographic behavior compared to its parents, therefore depending on the evolution of environmental risks, the response of the science of the time, the regularity with which socioeconomic crises occur, the outbreak of new diseases “The debate continues. (which are not considered here) and the evolution of the main causes of death at that time,” reflects Gómez Redondo, who did not participate in this research. calls Olshansky’s study “a remarkable contribution by a leading demographer” to the analysis of longevity.

Sotos Prieto attributes the slowdown in life expectancy at birth to the biological limits of aging. But it also highlights other possible causes, such as “unhealthy lifestyles, increasingly sedentary lifestyles and diets with poor nutritional quality.” “Maybe the other aspect is inequality in access to medical care. If it becomes smaller, it will still grow a little more,” he further said.

Life expectancy in Spain: 83.1 years

Professor Lola Sánchez Aguilera, specialist in regional geographical analysis at the University of Barcelona, ​​​​recalls in any case that the evolution of life expectancy is not always upward. There may be a surprise. “History has shown us that progress is not linear and that there can be setbacks. We have already faced some scares, like the AIDS epidemic or, more recently, Covid,” he warns. For example, in Spain, life expectancy at birth in 2022 – the latest year for which data are available – was 83.1 years (80.3 in men and 85.8 in women). According to the latest Health Ministry report published this Monday, these figures indicate that this is an improvement after the impact of the Covid pandemic – which led to a 1.5 year reduction in life expectancy in 2020 – but this has not yet been confirmed. Health has returned to pre-crisis levels (in 2019, life expectancy at birth was 83.5).

Gómez Redondo believes that, in the coming decades, “it is possible” that there will be a period of stagnation in life expectancy, followed by subsequent progress. And he defends: “It is conceivable that life expectancy will reach 100 or more years, but looking at the data, this will not happen in the 21st century.” To achieve this second revolution of longevity, demographers point to several directions: “reduction of mortality associated with population aging”, delay of biological aging, reduction of probability of death according to socioeconomic inequalities. and “elimination” or a change in the trend of premature death in adults, particularly at younger ages due to tumors, which has been increasing in recent decades in the world.

Gómez Redondo cautions that the single case of Calment, who reached the age of 122, is not feasible as a global life expectancy target: “It can be considered as a horizon to achieve, but life This is unimaginable as the anticipation of population growth on a global scale is likely, at least given the current state of scientific knowledge and the availability of health resources at the socio-economic level in the near future.”