Identification of a geographic area characterized by extreme longevity in the Sardinia island: the AKEA study.
Level 4 - case-series / case-control
Ecological and demographic spatial analysis of historical birth cohorts
PubMed 15489066 · doi:10.1016/j.exger.2004.06.016
What was done
Researchers calculated the Extreme Longevity Index (ELI), defined as the percentage of persons born in Sardinia between 1880 and 1900 who reached age 100. Using a Gaussian smoothing method, they mapped validated centenarian data across Sardinia to identify geographic areas with exceptional survival to extreme age.
What was found
The spatial analysis identified a geographic concentration of extreme longevity ('Blue Zone') in the mountainous central-eastern part of the island. In this area, life expectancy was higher than in the rest of Sardinia, particularly for men, and the female-to-male ratio among centenarians was 1.35 compared to 2.43 across the remainder of the island.
Why it matters
This study formally delineated the original Sardinian 'Blue Zone' and documented an unusually high rate of male survival to age 100, providing an empirical baseline for investigating genetic, familial, and environmental determinants of extreme human longevity.
Limits
The abstract does not state the total population or absolute number of centenarians analyzed. As an ecological demographic mapping study, it cannot determine the causal mechanisms underlying the observed longevity cluster, leaving hypotheses regarding inbreeding, genetics, or environmental factors unverified.
Cited by
- supports In Blue Zones, the proportion of centenarians is approximately 6 per 10,000 compared to 3 per 10,000 in the United States.