A Sardinian Mountain Village Emerges as a Candidate Longevity Blue Zone

Deep in the mountains of central Sardinia, roughly 110 kilometers from the island’s famous longevity hotspot, a village of barely 2,300 people is quietly rewriting the map of extreme human survival. Bolotana, a small municipality in the Marghine region that has never appeared on any blue zone map, now shows late-life survival figures that rival or exceed some of the most celebrated longevity regions on Earth, according to a new demographic analysis published in Frontiers in Aging. The finding is striking not only for its magnitude but for its pattern: unlike the original Sardinian Blue Zone, where exceptional longevity was historically concentrated in men, Bolotana’s advantage is overwhelmingly female.

The research team, led by Giovanni Mario Pes of the University of Sassari and including longevity researchers Steven Austad, Dan Buettner, Hiram Beltrán-Sánchez, and S. Jay Olshansky, set out to determine whether Bolotana exhibits a demographic profile compatible with a candidate longevity blue zone. The term blue zone originated from the blue markings researchers used when first mapping Sardinian longevity hotspots in the early 2000s, and it has since come to describe geographically circumscribed populations with exceptionally favorable survival relative to their national contexts. But the concept has come under pressure in recent years. Standardized reassessments suggest that the longevity advantage of some historically documented blue zones, particularly Okinawa in Japan and Nicoya in Costa Rica, has weakened over time, possibly because other populations have caught up, because late-life mortality improvements have slowed generally, or because the favorable early-life exposures that shaped early twentieth-century cohorts have faded through cohort replacement.

Against that backdrop, Bolotana offered an unusual opportunity. The village combines substantial residential continuity with remarkably complete civil and parish records stretching back generations, making rigorous age validation possible. The researchers pulled demographic information from the municipal civil registry, including sex, dates and places of birth and death, residence, and migration status, and then cross-checked civil birth records against independent parish registers of baptisms, deaths, and burials. Record linkage relied on concordance of names, dates, parentage, and family relationships, with genealogical timelines reconstructed when necessary to rule out confusion between siblings or relatives sharing the same name. Civil birth documentation was available for every identified centenarian, and 97 percent of recorded centenarian deaths were independently verified against parish archives. No centenarian case had to be excluded for insufficient age documentation.

The core of the analysis is a pair of period life-table indicators built from deaths and person-years of exposure aggregated over 2021 to 2025. The first is remaining life expectancy at age 70, written e70, which measures how many additional years a person who reaches 70 can expect to live under the mortality conditions of the observation period. The second is conditional survival from age 70 to exact age 100, or S(70→100), the probability that a 70-year-old survives three more decades. Because Bolotana is small, the researchers quantified statistical uncertainty with a parametric Poisson bootstrap: in each of 20,000 replications, death counts at each single year of age from 70 to 99 were regenerated from fitted Poisson distributions while observed person-years of exposure were held fixed, a complete life table was rebuilt, and the two indicators were extracted. The 2.5th and 97.5th percentiles of the resulting distributions defined the 95 percent confidence limits. The mortality rate in the open interval at age 100 and older was deliberately held fixed, since resampling the handful of deaths in that terminal range could produce zero-death scenarios in which the life table could not be closed.

The headline results concern women. During 2021 to 2025, remaining life expectancy at age 70 for Bolotana women was 20.85 years, with a 95 percent confidence interval of 19.42 to 22.43 years. That figure exceeds not only the contemporary means for Nuoro Province (18.61 years), Sardinia as a whole (18.40 years), and Italy (18.06 years), but also the highest annual value recorded in each of those reference populations. Even more dramatic is conditional survival to age 100: 13.83 percent of Bolotana women who reach 70 are estimated to live to 100, with a confidence interval of 7.33 to 23.75 percent. That is more than three times the corresponding figures for Nuoro Province (4.33 percent), Sardinia (4.43 percent), and Italy (3.54 percent), and more than three times the value for women in the United States. Among the international benchmarks drawn from the Human Mortality Database, Bolotana women ranked second only to Hong Kong on both indicators.

Men in Bolotana also fared well, though less spectacularly. Their remaining life expectancy at age 70 was 16.02 years (95 percent CI, 14.55 to 17.79), modestly above the means for Nuoro Province, Sardinia, and Italy, and their conditional survival to 100 was 4.92 percent (95 percent CI, 1.58 to 12.76), higher than any annual value observed in the three reference populations, which ranged from 1.41 to 1.74 percent. The much wider confidence interval around the male survival estimate reflects the hard statistical reality of estimating extreme-age survival in a small population: during the five-year window, Bolotana recorded 149 deaths at ages 70 and older, 69 in men and 80 in women, and 19 residents reached age 100, five men and fourteen women, six of whom were still alive at the end of follow-up. The authors are careful to note that because the reference values are descriptive annual summaries rather than inferential estimates, these comparisons should not be read as formal tests of statistical significance.

How robust are these numbers? The team stress-tested them from several directions. An alternative constant-force-of-mortality specification for converting central mortality rates into annual death probabilities produced essentially identical results, with survival estimates differing by less than 0.10 percentage points. A binomial Monte Carlo procedure, built on Chiang’s Bernoulli-trial framework, yielded uncertainty intervals very similar to the Poisson bootstrap. Extending the observation window to include 2020, the first year of the COVID-19 pandemic, produced modest reductions, with female life expectancy at 70 falling from 20.85 to 20.37 years and female survival to 100 dropping from 13.83 to 12.48 percent, but the pronounced female advantage persisted. The most consequential sensitivity check, however, was temporal. When the researchers repeated the analysis for the period-matched window of 2015 to 2019, Bolotana’s late-life survival profile was distinctly less favorable, particularly for survival to age 100: male e70 fell to 13.87 years and male S(70→100) to just 0.77 percent, while female values were 18.30 years and 1.46 percent, all well below the original Sardinian Blue Zone’s published 2015 to 2019 estimates.

That period sensitivity is the study’s central caution. Comparing Bolotana’s 2021 to 2025 estimates with the pooled 2015 to 2019 figures for the fourteen municipalities of the original Sardinian Blue Zone shows Bolotana women ahead on both indicators, 20.85 versus 20.30 years of life expectancy at 70 and 13.83 versus 8.76 percent survival to 100, while Bolotana men trail slightly. But because those estimates come from different calendar periods, the authors treat them strictly as a historical benchmark rather than evidence of superiority. The 2015 to 2019 sensitivity analysis, which required grouping the sparse oldest-age data into five-year age bands under a constant-force assumption, suggests that Bolotana’s apparent advantage is partly a feature of the specific window examined. Short calendar periods, small populations, and stochastic variation in deaths at extreme ages all conspire to make any single five-year estimate fragile.

A complementary cohort-based analysis adds historical depth. The researchers calculated the Extreme Longevity Index for everyone born in Bolotana between 1900 and 1925: of 3,060 registered live births, 38 individuals were documented as reaching age 100, an index of 1,242 centenarians per 100,000 live births, with an exact 95 percent confidence interval of 880 to 1,701. The comparable reported Italian figure is 793 per 100,000. Because the index measures realized survival from birth, it is shaped by early- and midlife mortality as well as survival at advanced ages, and incomplete follow-up of the roughly 3 percent of emigrants who could not be traced to a documented death may have slightly understated it. Still, it points to a long-standing local propensity for centenarian survival that predates the current observation window.

What explains the pattern remains an open question. The authors list plausible contributors to the female survival advantage, including genetic background, dietary patterns, physical activity, family support, social cohesion, continuity of residence, and access to care, but the demographic data alone cannot determine whether any of these factors actually drove the observed numbers. Bolotana’s mountainous setting and low density may also have shaped its pandemic-era exposure, though the absence of individual-level data on infection, vaccination, and cause of death prevents testing that idea. The study’s limitations are candidly acknowledged: a small population, wide confidence intervals, a short observation period overlapping COVID-19, and descriptive rather than inferential comparisons. Taken together, the age validation, the life-table estimates, and the sensitivity analyses support considering Bolotana a candidate longevity blue zone, with a distinctive, predominantly female profile that contrasts with the male-centered pattern of the original Sardinian hotspot. But the evidence does not yet justify calling it an established one. Longer observation, continued demographic validation, and individual-level comparative studies will be needed to determine whether this mountain village’s exceptional survival is a durable feature of the community or a fleeting alignment of cohort and calendar.

Subject of Research: Demographic analysis of exceptional late-life survival and centenarian prevalence in Bolotana, Sardinia, as a candidate longevity blue zone

Article Title: A new blue zone? exceptional late-life survival in Bolotana, Sardinia

Article References: Pes, G. M., Austad, S. N., Buettner, D., Pedde, S., Romerio, V., Beltrán-Sánchez, H., & Olshansky, S. J. (2026). A new blue zone? exceptional late-life survival in Bolotana, Sardinia. Frontiers in Aging, 7, Article 1951042. https://doi.org/10.3389/fragi.2026.1951042

Image Credits: AI Generated

DOI: 10.3389/fragi.2026.1951042

Keywords: blue zones, exceptional longevity, Sardinia, Bolotana, life expectancy, centenarians, late-life survival, period life tables, demography, extreme longevity index, aging research, small populations