Supercentenarians: the oldest people in the world.

Epidemiologists are now interested in supercentenarians. They are the subjects who had reached 110 years of age, in a validated manner. Information on their nationality, date of birth, the gender, and the year of eventual death is known.To evaluate the prevalence of supercentenarians is a complicated task. It is correlated with the same conditions which determine the ageing of the population, and particularly that of the centenarians. Therefore, it is variable region by region, and in various ethnic groups. Values have been estimated as about 0.25-0.50 per cent1, or 0.150.25 per cent2 of the centenarians. Identified and alive supercentenarians were (June, 2009) 82 (74 females and 8 males). Their presence in the world is estimated as about 350-450 subjects2. The International Database of Longevity estimates that during the last 50 years there have been about 1000 supercentenarians. The factors responsible for the extreme longevity are multiple, and among them the genetic ones are of fundamental importance, even if these may not be considered as exclusive ones1,3. A comparative evaluation of the prevalence of supercentenarians in a multiracial country may be of particular importance. For example, in US, the black population represents the second large group of centenarians, contrasting that of the African countries, displaying the lowest medium life span4. It is important, however, that the ratio of prosperity/longevity in a country is valid up to a certain value of the GDP. As a matter of fact, the Preston-curve has shown that this factor is valid up to an annual income of US$ 5000 per person/year4. The USA with a GDP of US$ 37,650 per person/year (the highest in the world) occupies only the 45th place in the ranking of life expectancy5. From these data, it should be noted that India is on the 145th place of nations5 in the ranking of the life expectancy, it has a modest GDP per person, but a very large sample number, and yet has a single validated supercentenarian, Lucy d’Abreu, a Scottish women born in 1892 in Dharwar (India) and died at the age of 113 years and 197 days in Stirling (Scotland). Probably a careful nosographic research and a consequent validation procedure could confirm numerous ultracentenarians in India, and also the presence of several dozens of supercentenarians. on the basis of the statistical evaluation. The ageing process cannot be considered as being only under the genetic control.