Longevity gains made in the first half of the 20th century have significantly slowed down in recent decades, according to a new study.
The study, published in the journal PNAS, analysed life expectancy trends for 23 nations with high incomes and low death rates using data from the Human Mortality Database and six different mortality forecasting methods and concluded that no generation born after 1939 was likely to reach 100 years on average.
“The unprecedented increase in life expectancy we achieved in the first half of the 20th century seems to be a phenomenon we are unlikely to achieve again in the foreseeable future,” said study co-author Héctor Pifarré i Arolas from the University of Wisconsin-Madison in the US. “In the absence of any breakthroughs that significantly extend human life, life expectancy will still not match the rapid increases seen in the early 20th century even if adult survival improves twice as fast as we predict.”
Between 1900 and 1938, life expectancy rose by nearly five and a half months with each new generation.
While the average life expectancy of a person born in a high-income country in 1900 was 62 years, it was 80 years for someone born just 38 years later.
The surge slowed down to about three months for subsequent generations born between 1939 and 2000.
“We forecast that those born in 1980 will not live to be 100 on average and none of the cohorts in our study will reach this milestone,” José Andrade, another study author from the Max Planck Institute for Demographic Research, said. “This decline is largely due to the fact that past surges in longevity were driven by remarkable improvements in survival at very young ages.”
Infant death rates fell at the beginning of the 20th century due to medical advances and improvements in the quality of life for high-income countries, leading to a rapid increase in life expectancy.
Today, infant and child mortality are so low that predicted improvements among older age groups will not be enough to sustain the previous pace of longevity gains.
“Even if our forecasts are overly pessimistic, a reversal is unlikely,” researchers said.
Researchers hope the findings can offer critical insights for governments to anticipate the needs of their healthcare systems, pension planning and social policies.
