Radical extension of the human lifespan, science fiction or reality?
Humans have long been fascinated with maximizing human lifespan, possibly driven by a universal desire for more time. Average life expectancy at birth dramatically increased in the 20th century, due to improved sanitation, reduced infant mortality, reduced infectious mortality thanks to antibiotics, and preventative treatment of cardiovascular disease. But will the trajectory of rapid lifespan extension continue? A recent study examined the trends in mortality rates from the last three decades to determine if the projected average lifespan at birth is expected to keep increasing at rapid rates in the already longest-lived countries. 1
At the beginning of the 20th century in the United States, life expectancy at birth was about 47 years, whereas by midcentury, life expectancy increased to around 66 years for men and 71 years for women. Life expectancy increased to about 78 years by the end of the century. This 66% increase in life expectancy works out to a yearly average increase of about 0.33 years, the current standard for what is considered radical life extension (a yearly increase of 0.3 years, or 3 years per decade).
In the present study, investigators Olshansky and colleagues used the annual age-specific and sex-specific death rates and period life expectancy at birth from 1990–2019 derived from the Human Mortality Database to assess whether the trend of radical life extension has continued in the past three decades. They used information from the eight countries with the longest-lived populations to evaluate trends in life expectancy and the effects of hypothetical reductions in mortality. Also included in the analysis were Hong Kong, a more recent area with a longer-living population, and the United States, which is sadly not among the top countries for life expectancy, but serves as an important comparison. (The U.S., despite its status as a very wealthy nation, saw rising mortality of its middle-age population between 2010 to 2019 and currently has an approximately 8-year lower life expectancy at birth than the longest-lived populations.)
