An analysis of 23 high‑income countries published in PNAS finds the rapid longevity gains of the early 20th century have slowed markedly for cohorts born after 1939, and none of those cohorts are projected to average 100 years of life.
A peer‑reviewed study in the Proceedings of the National Academy of Sciences examines cohort life expectancy across 23 high‑income, low‑mortality countries and concludes that the pace of longevity improvement has decelerated for people born from 1939 to 2000. The research uses data from the Human Mortality Database and six established forecasting methods to complete the life histories of these birth cohorts.
What the study did
- Estimated cohort (birth‑year) life expectancy rather than period life expectancy, which better reflects the actual longevity of people born in a given year.
- Drew on the Human Mortality Database for 23 wealthy countries and applied six forecasting techniques (including Lee–Carter and related cohort/period variants) to project remaining mortality for cohorts born after 1938.
- Authored by José Andrade (Max Planck Institute for Demographic Research), Carlo Giovanni Camarda (Institut national d’études démographiques), and Héctor Pifarré i Arolas (University of Wisconsin–Madison).
Key findings
- For cohorts born between 1900 and 1938, the frontier pace of improvement averaged about 0.46 years per birth cohort.
- Forecasts for cohorts born from 1939 to 2000 indicate a slower pace—down by roughly 37% to 52% versus the 1900–1938 trend.
- Under these forecasts, none of the cohorts analyzed are expected to reach a cohort life expectancy of 100 years. The authors note that only an optimistic straight‑line extrapolation of the pre‑1939 trend would have hit 100 around the 1980 birth cohort.
- The deceleration is driven mainly by a diminished contribution from very young ages: more than half of the slowdown is attributable to mortality trends under age 5, and over two‑thirds to trends under age 20.
Why the slowdown matters
- In the early 20th century, large drops in infant and child mortality propelled rapid gains in average lifespan. With early‑age mortality already very low in high‑income countries, further progress depends more on improving survival at older ages—gains that, while possible, are not projected to match the earlier pace.
What the authors say
- “The unprecedented increase in life expectancy we achieved in the first half of the 20th century [is] unlikely to [recur] in the foreseeable future,” said co‑author Héctor Pifarré i Arolas in a university news release.
- Lead author José Andrade added that, on current projections, “those born in 1980 will not live to be 100 on average,” and none of the post‑1939 cohorts in the study are forecast to reach that milestone.
Policy context and caveats
- The authors emphasize that forecasts are uncertain. New pandemics, medical breakthroughs, or major social changes could alter trends. Still, current evidence points to a long‑term slowdown in longevity growth among today’s older and middle‑aged generations.
- Slower gains in life expectancy have implications for governments and households—from pension and long‑term‑care planning to savings and retirement timing.