Limits to Human Longevity
Title
Limits to Human Longevity
Author
Preston, Samuel H.
Beltrán‐Sánchez, Hiram
Research Area
Social Processes
Topic
Population Dynamics
Abstract
Longevity has increased sharply in the past century and it is likely to continue increasing. Historical trends in maximum life expectancy at birth show major improvements since 1760. Life expectancy at age 80 has also improved with an accelerating pace in recent years suggesting we are not approaching a biological limit to the length of life. Anticipating the near future of longevity typically relies on extrapolating either longevity itself or age‐specific death rates. The principal alternative to extrapolative methods attempts to model factors affecting mortality and to project those factors into the future. In the more distant future, rather than targeting specific diseases, much research would attempt to arrest the aging process itself either through gene therapy or through medicines that replicate the genes' activities. Stem cell technologies may make it possible to create new body organs to replace defective ones. Although discoveries in laboratories will play an important role in determining the future of longevity, many puzzles remain to be worked out in translating individual behaviors into population‐level indexes. Quasi‐experimental designs may provide a useful approach to investigate systemic determinants of mortality, with implications for the future of longevity. In addition to projections of longevity for national populations, there would also be projections for major groups within populations. Future projections of longevity are likely also to involve much more consideration of the epidemiology of diseases and their interactions. Finally, an attractive approach to longevity is to base projections on birth cohorts instead of, or in addition to, period‐specific data.