A recent U.S. study suggests that humans are unlikely to see major increases in lifespan this century, as life expectancy growth has slowed over the past 30 years in high-longevity nations like Japan. Conducted by researchers from the University of Illinois and others, and published in *Nature Aging*, the study projects that by the century's end, only around 15% of women and 5% of men will reach the age of 100.

Examining data from long-lived populations in countries such as Japan, South Korea, Switzerland, and Hong Kong, the study found an average life expectancy increase of 6.5 years from 1990 to 2019. Although the 20th century saw substantial gains in lifespan due to advances in sanitation, medicine, and health for older adults, this growth rate has slowed considerably in recent decades.

According to composite mortality data, life expectancy for those born in 2019 is estimated at 88.68 years for women and 83.17 years for men, with survival probabilities to age 100 at 13.9% for women and 4.5% for men. To achieve a life expectancy of 110 years, nearly 70% of women would need to survive to age 100, a scenario the study suggests would require curing most current causes of death.

The study concludes that "without significant slowing of biological aging, radical life extension for humans is unlikely this century." As of 2023, Japan's Ministry of Health reports average life expectancies of 87.14 years for women and 81.09 years for men, with a record 95,119 people aged 100 or older, 88.3% of whom are women.