A new study co-authored by a University of Wisconsin–Madison professor has found that the extraordinary life expectancy gains made by high-income countries in the first half of the 20th century have slowed dramatically. The researchers conclude that no generation born after 1939 will achieve an average lifespan of 100 years, marking a significant shift in expectations about longevity.
The study, published in the Proceedings of the National Academy of Sciences, was carried out by Héctor Pifarré i Arolas of the La Follette School of Public Affairs, José Manuel Aburto Andrade of the Max Planck Institute for Demographic Research, and Carlo Giovanni Camarda of the Institut national d’études démographiques. Using data from the Human Mortality Database, the team examined life expectancy trends in 23 high-income, low-mortality countries, applying six different statistical models to forecast how future lifespans might unfold.
According to Pifarré i Arolas, the steep rise in life expectancy achieved in the early 20th century was “unprecedented” and unlikely to be repeated. Even if survival among adults were to improve at twice the currently expected rate, the overall gains would not match the rapid increases of that earlier era. The analysis highlights the unique impact of that historical moment, when medical breakthroughs, better public health, and improved living conditions drastically reduced the risk of dying young.
Between 1900 and 1938, life expectancy in high-income countries rose by roughly five and a half months with each new generation. A child born in 1900 could expect to live to 62, while someone born in 1938 had a projected lifespan of 80. After 1939, however, the pace of improvement slowed to just two and a half to three and a half months per generation, depending on the forecasting method used. This decline reflects the diminishing influence of infant and child survival on overall longevity.
As Andrade explained, the dramatic gains of the past were fuelled mainly by falling child mortality, whereas future progress now depends almost entirely on extending survival at older ages. With infant and child mortality already at very low levels in high-income countries, advances in longevity are harder to achieve. The researchers forecast that those born in 1980, for example, will not reach 100 years of age on average, nor will any subsequent cohort included in their analysis.
While no projection can fully account for the possibility of unexpected developments such as pandemics, medical innovations, or societal upheavals, the study provides important insights for policymakers. Slower growth in life expectancy has profound implications for healthcare systems, pension schemes, and social planning, while also shaping individual choices about savings, retirement, and long-term care. In short, both governments and citizens need to recalibrate their expectations of human longevity in the 21st century.
More information: Héctor Pifarré i Arolas et al, Cohort mortality forecasts indicate signs of deceleration in life expectancy gains, Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.2519179122
Journal information: Proceedings of the National Academy of Sciences Provided by University of Wisconsin-Madison
