WEDNESDAY, Sept. 3, 2025 (HealthDay News) -- The previously observed pace of improvement in life expectancy has declined, according to a study published online Aug. 25 in the Proceedings of the National Academy of Sciences.José Andrade, from the Max Planck Institute for Demographic Research in Rostock, Germany, and colleagues estimated cohort life expectancy for individuals born between 1939 and 2000 in 23 high-income countries by applying multiple established and recently developed mortality forecasting methods.The researchers found that the results robustly and consistently indicated a deceleration in cohort life expectancy across all forecasting methods. Depending on the method used, the previously observed pace of improvement, 0.46 years per cohort, declined by 37 to 52 percent. These findings were considered unlikely to be solely due to downward bias in cohort life expectancy forecasts in robustness checks. This deceleration was mainly driven by a slower pace of mortality improvement at very young ages in an age-decomposition analysis. More than half of the total deceleration was attributable to mortality trends under age 5 years, while more than two-thirds was attributable to trends under age 20 years."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," Andrade said in a statement. "This decline is largely due to the fact that past surges in longevity were driven by remarkable improvements in survival at very young ages."Abstract/Full Text.Sign up for our weekly HealthDay newsletter