The Odds of Living to 110 Level Off After Age 105: New Analysis of Italian Supercentenarians

Summary: Researchers report that death rates slow and then plateau after age 105. The study suggests there is no fixed, clearly defined limit to the human lifespan yet in sight.

Source: UC Berkeley.

Reaching 110 may be closer than commonly believed for those who survive into their later years: new research shows that once people reach about 105 years of age, their annual mortality risk stabilizes. The findings are based on a rigorous analysis of extraordinarily old Italians and were led by investigators at the University of California, Berkeley, and Sapienza University of Rome.

The study followed nearly 4,000 Italian residents who were 105 or older between 2009 and 2015 and examined the trajectory of their mortality rates. Researchers found that after age 105 the risk of dying in the following year no longer increases, producing a clear plateau in late-life mortality.

The paper, appearing in the journal Science, challenges prior claims that human lifespans must end at a fixed maximum. The longest verified lifespan on record remains Jeanne Calment of France, who died in 1997 at age 122, but the new results suggest a strict biological cap is not yet evident.

“Our data tell us that there is no fixed limit to the human lifespan yet in sight,” said Kenneth Wachter, a professor emeritus of demography and statistics at UC Berkeley and the study’s senior author. “Not only do we see mortality rates that stop getting worse with age, we see them getting slightly better over time.”

The analysis indicates that semi-supercentenarians—people aged 105 to 109—face roughly a 50 percent chance of dying within the next year, with an average remaining life expectancy of about 1.5 years. That same expectation appears to extend to individuals who reach 110, the supercentenarians, which creates the plateau effect in late-life hazard rates.

By contrast, survival prospects at younger advanced ages remain more precarious. The researchers illustrate this with nonagenarians: for example, Italian women born in 1904 who reached age 90 had an approximately 15 percent chance of dying within a year and an average remaining lifespan of six years. If those women reached 95, their one-year mortality risk rose to 24 percent and their remaining life expectancy fell to about 3.7 years.

The dataset comprised 3,836 documented cases of Italians born between 1896 and 1910 who survived to age 105 or beyond. The authors credit the Italian National Institute of Statistics for exceptionally reliable age records, noting that the national validation system records age at death down to the nearest day. This thorough documentation strengthens confidence in the study’s estimates for extreme-age mortality.

Researchers interpret the plateau in the context of demographic and evolutionary processes. One explanation is selection: frail individuals tend to die earlier, leaving a progressively more robust subset of the cohort at extreme ages. Natural selection and genetic differences in resilience may also contribute, so those who reach extreme ages are disproportionately robust or genetically advantaged. Similar patterns of late-life mortality plateaus have been observed in other species, such as fruit flies and nematode worms, suggesting a common evolutionary mechanism in aging dynamics.

The study’s lead author is Elisabetta Barbi of Sapienza University of Rome. Co-authors include Francesco Lagona (Roma Tre University), Marco Marsili (Italian National Institute of Statistics), James Vaupel (University of Southern Denmark, Duke University, and the Max Planck Institute for Demographic Research), and Kenneth W. Wachter (UC Berkeley).

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Original research: “The plateau of human mortality: Demography of longevity pioneers” by Elisabetta Barbi, Francesco Lagona, Marco Marsili, James W. Vaupel, and Kenneth W. Wachter in Science. Published June 27, 2018. doi:10.1126/science.aat3119

The plateau of human mortality: Demography of longevity pioneers

Theories about biological limits to lifespan and the evolutionary shaping of human longevity rely on accurate facts about mortality at extreme ages, but those facts have been debated. Do hazard curves eventually level into high plateaus, as observed in other species, or do exponential increases continue without bound? This study estimated hazard rates using data on all inhabitants of Italy aged 105 and older between 2009 and 2015 (birth cohorts 1896–1910), a total of 3,836 documented cases. The authors observed essentially flat hazard curves beyond age 105. These estimates avoid artifacts from aggregation that affected earlier work and offer strong evidence for the existence of extreme-age mortality plateaus in humans.

human lifespan, longevity, mortality plateau, supercentenarian, extreme-age mortality, aging research, demographic selection