A study by American scientists has shown that, since 1990, the overall increase in life expectancy has slowed compared to earlier periods. According to an article published in the journal Nature Aging, the percentage of people who will live to be 100 is unlikely to exceed 15 percent for women and 5 percent for men.
Until the mid-19th century, life expectancy at birth ranged from 20 to 50 years. Advances in public health and medicine in the early 20th century led to a sharp increase in life expectancy, reaching up to 100 years. However, the rate of increase in life expectancy at birth continued to be influenced by geographic location, economic development, and time factors. Overall, the transition to longer lifespans consisted of a decline in early mortality, followed by a decline in old age.
Accurately forecasting future trends in life expectancy is important for social, health, and economic policy. For example, it is known that some countries are experiencing a significant increase in the proportion of the elderly (i.e., non-working) population. Various theories have predicted different life expectancy ceilings, but these can only be confirmed or refuted retrospectively.
A research team led by S. Jay Olshansky of the University of Illinois at Chicago used standard demographic survival rates from the ten countries with the longest life expectancies (Australia, Hong Kong, Spain, Italy, the United States, France, Switzerland, Sweden, South Korea, and Japan) from approximately 1990 to 2019 to determine which hypothesis about human life expectancy was supported by the data. It found that life expectancy at birth in 2019 was 88.68 years for women and 83.17 years for men.
The initial analysis showed that the only countries to achieve an increase in life expectancy of 0.3 years annually or 3.0 years over a decade (the de facto definition of radical life extension) were South Korea and Hong Kong. In Hong Kong, where life expectancy increased by 6.5 years, this was largely due to economic prosperity and tobacco control, but the main increase in life expectancy occurred in the 1990s. Overall, in all the countries studied, with the exception of Hong Kong and South Korea, the annual increase in life expectancy has slowed compared to the 20th century and is less than 0.2 years per year.
Between 1950 and 2019, age at death declined to a shorter period of time at the limit of human survival. Since 1990, life expectancy has not increased at a rate that would warrant radical life extension, and this is unlikely to happen without breakthroughs in slowing the rate of human aging. The average probability of newborns in the countries studied surviving to 100 is 5.1 percent for women and 1.8 percent for men, with the highest population probability of surviving to 100 in Hong Kong, where 12.8 percent of women and 4.4 percent of men will reach 100 during their lifetime.
The scientists also used Japan as an example to demonstrate how mortality must be reduced to increase life expectancy at birth by one year. All-cause mortality at any age, required to increase life expectancy for women to 89 years, would need to decrease by 20.3 percent. For men, increasing life expectancy from 82 to 83 years would require a 9.5 percent reduction in overall mortality at each age.
A second wave of radical lifespan improvement, which would increase life expectancy at birth by 110 years, would require approximately 70 percent of women to live to 100, and 24 percent to 122—the maximum lifespan recorded for humans. Another six percent of women would need to live to 150.
However, these results may change after adjusting for the COVID-19 pandemic. As we've already reported, it reduced life expectancy by 1.8 years.
