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Researchers base calculations on six different methods and reach the same conclusion
Life expectancy rose rapidly in the first half of the 20th century, increasing from an average of 62 years for people born in 1900 to 80 years for those born in 1938. But will those born between 1939 and 2000 benefit from these rapid gains in longevity? A recent study suggests that none of these generations will reach 100 years of age on average. Even if adult survival improved twice as fast as we predict, cohort life expectancy would still not match the rapid increases seen in the early 20th century.
The question of how far life expectancy will rise in future is a highly controversial topic among scientists. From today's perspective, life expectancy rose at an almost dizzying rate at the beginning of the 20th century. People born in 1900 lived to an average age of 62, whereas those born in 1938 lived to around 80. In a study recently published in the journal Proceedings of the National Academy of Sciences (PNAS), José Andrade (Max Planck Institute for Demographic Research (MPIDR)), Carlo Giovanni Camarda (Institut national d'études démographiques – INED), and Héctor Pifarré i Arolas (University of Wisconsin-Madison), investigated whether people born between 1939 and 2000 will achieve similar increases in life expectancy. The analysis was performed for 23 high-income and low-mortality countries.
"If today's generations were to follow the same trend as the one observed during the first half of the 20th century, someone born in 1980, for example, could expect to live to 100," explains José Andrade, first author of the study and researcher at MPIDR. "We investigated whether the pace of life expectancy gains is slowing down for current alive cohorts.” To achieve this, the scientist and his colleagues predicted the life expectancy of these generations. Their calculations were based on data from the Human Mortality Database (HMD). Using six different mortality forecasting methods—statistical techniques that make informed predictions about future lifespans based on past and current mortality information—the research team estimated how life expectancy will develop.
"To ensure robust results, we did not just use one method, but several: some well-established ones, including the United Nations World Population Prospects, and others representing the cutting edge of mortality forecasting," said Andrade.
Two main approaches were used to complete the cohort mortality profiles:
Period-based methods: These include methods such as Lee-Carter, Smooth Constrained Mortality, Compositional Data Analysis and United Nations World Population Prospects (2024)
Cohort-based methods, including Linear Lee-Carter and Cohort Segmented Transformation Age-at-death Distributions
Figure showing six graphs displaying six different methods to forecast life expectancy. All curves look very similar
Little room for improvement
"All forecasting methods show that life expectancy for those born between 1939 and 2000 is rising more slowly than in the past. Depending on the method used, the rate is slowing by between 37 and 52 per cent," explains the scientist. "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. This decline is largely due to the fact that past surges in longevity were driven by remarkable improvements in survival at very young ages." At the beginning of the 20th century infant mortality fell rapidly due to medical advances and other improvements. This is what caused the rapid increase in life expectancy at the beginning of the 20th century. However, mortality in these age groups is already so low that there is little room for improvement. The researchers' forecasts indicate that mortality in older age groups will not improve quickly enough to compensate for this decline.
From 1900 to 1938, life expectancy rose by about five and a half months with each new generation. For those born between 1939 and 2000, the increase slowed to roughly two and a half to three and a half months per generation, depending on the forecasting method.
Andrade, Camarda, and Pifarré i Arolas regard this result as highly robust. They argue that even if the survival among adults and older individuals were to improve at twice the rate predicted in the forecasts, the resulting gains in life expectancy would still fall short of those achieved in the first half of the 20th century.
Forecasts are predictions, not certainties
Mortality forecasts can never be certain as the future may unfold in unexpected ways. Events such as pandemics, new medical treatments or societal changes can significantly affect actual life expectancy. Consequently, life expectancy may not align with anticipated trends. Therefore, forecasts should always be considered as educated estimates. It is important to note that these forecasts apply to populations, not individuals.
Why is life expectancy research so important?
Changes in life expectancy affect social cohesion and personal life planning. Governments must adapt healthcare systems, pension planning and social policies. At the same time, life expectancy influences personal decisions about saving, retirement and long-term planning. If life expectancy increases more slowly, both governments and individuals may need to recalibrate their expectations for the future.
José Andrade
Research Scientist
Max Planck Institute for Demographic Research (MPIDR)
andrade@demogr.mpg.de
José Andrade, Carlo Giovanni Camarda, Héctor Pifarré i Arolas: Cohort mortality forecasts indicate signs of deceleration in life expectancy gains in PNAS (2025), DOI: 10.1073/pnas.2519179122
https://www.demogr.mpg.de/en/news_events_6123/news_press_releases_4630/press/coh...
Cohort Mortality Forecasts Indicate Signs of Deceleration in Life Expectancy Gains
Quelle: MPIDR
Copyright: MPIDR
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