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Driven by technological progress, human life expec Driven by technological progress, human life expectancy has increased greatly since the nineteenth century. Demographic evidence has revealed an ongoing reduction in old-age mortality and a rise of the maximum age at death, which may gradually extend human longevity1,2. Together with observations that lifespan in various animal species is flexible and can be increased by genetic or pharmaceutical intervention, these results have led to suggestions that longevity may not be subject to strict, species-specific genetic constraints. Here, by analysing global demographic data, we show that improvements in survival with age tend to decline after age 100, and that the age at death of the world’s oldest person has not increased since the 1990s. Our results strongly suggest that the maximum lifespan of humans is fixed and subject to natural constraints. Maximum lifespan is, in contrast to average lifespan, generally assumed to be a stable characteristic of a species3. For humans, the
maximum reported age at death is generally set at 122 years, the age at death of Jeanne Calment, still the oldest documented human
individual who ever lived4. However, some evidence suggests that
maximum lifespan is not fixed. Studies in model organisms have shown that maximum lifespan is flexible and can be affected by genetic and pharmacological interventions5. In Sweden, based on a long series of reliable information on the upper limits of human lifespan, the
maximum reported age at death was found to have risen from about
101 years during the 1860s to about 108 years during the 1990s6. According to the authors, this finding refutes the common assertion that human lifespan is fixed and unchanging over time6. Indeed, the most convincing argument that the maximum lifespan of humans is not fixed is the ongoing increase in life expectancy in most countries over the course of the last century1,2. Figure 1a shows this increase for France, a country with high-quality mortality data, but very similar patterns were found for most other developed nations (Extended Data Fig. 1). Hence, the possibility has been considered that mortality may decline further, breaking any pre-conceived boundaries of human lifespan1,7. As shown by data from the Human Mortality Database8, many of the historical gains in life expectancy have been attributed to a
reduction in early-life mortality. More recent data, however, show
evidence for a decline in late-life mortality, with the fraction of each birth cohort reaching old age increasing with calendar year. In France, the number of individuals per 100,000 surviving to old age (70 and up) has increased since 1900 (Fig. 1b), which points towards a continuing increase in human life expectancy. This pattern is very similar across the other 40 countries and territories included in the database (Extended Data Figs 2, 3). However, the rate of improvement in survival peaks and then declines for very old age levels (Fig. 1c), which points
1Department of Genetics, Albert Einstein College of Medicine, Bronx, New York 10461, USA. 2Department of Ophthalmology & Visual Sciences, Albert Einstein College of Medicine, Bronx, New York 10461, USA. *These authors contributed equally to this work.
1900 1950 2000 1
100
10,000
Female
Survivors per 100,000
1900 1950 2000
Male
Age (years) 70 80 90 100 105 110
1920 1940 1960 1980 2000
80
85
90
95
100
Year
Age with greatest gain (years)
1900 1920 1940 1960 1980 2000
30 40 50 60 70 80
Year
Life expectancy at birth (years)
Female Male
0204060801 00
0.02
0
0.04
0.06
Age (years)
Rate of change since 1900
Female Male
ab
cd
Figure 1 | Trends in life expectancy and late-life survival. a, Life expectancy at birth for the population in each given year. Life expectancy in France has increased over the course of the 20th and early 21st centuries. b, Regressions of the fraction of people surviving to old age demonstrate that survival has increased since 1900, but the rate of increase appears to be slower for ages over 100. c, Plotting the rate of
change (coefficients resulting from regression of log-transformed data) reveals that gains in survival peak around 100 years of age and then rapidly decline. d, Relationship between calendar year and the age that experiences the most rapid gains in survival over the past 100 years. The age with most rapid gains has increased over the century, but its rise has been slowing and it appears to have reached a plateau... |