A centenarian is a person who has attained the age of 100 years or more. Because current average life expectancies across the world are less than 100, the term is invariably associated with longevity. Much rarer, a supercentenarian is a person who has lived to the age of 110 or more, something only achieved by one in a thousand centenarians.
The United States currently has the greatest number of centenarians in the world, numbering over 55,000 in the year 2005. The U.S. number is partly a function of America's large population in 1890-1905, and an increased emphasis on long-term care facilities.
Japan is second, with 30,000. Many experts attribute this (and Japan's very high life expectancy) to the Japanese diet, which is particularly low in fats. In addition, five times as many Okinawans live to be 100 than the rest of Japan.
While the density of centenarians per capita was much less in ancient times than today, the data suggest that reaching the age of 100 was not impossible then. Though ancient demographics are biased in favor of wealthy or powerful individuals rather than the ordinary person, it is unscientific to suggest that "ordinary persons" lived longer. Grmek and Gourevitch speculate that during the Classical Greek Period, anyone who made it past the age of five years — surviving all the common childhood illness of that day — had a reasonable chance of living to a ripe old age. Life expectancy at 400 B.C. was estimated to be around 30 years of age. One demographer of ancient civilizations reported that Greek men lived to 45 years (based on a sample size of 91), while women lived to 36.2 years (based on a sample size of 55). Curiously, the gender statistics are inverted compared to today, since child-birth was a much more traumatic experience at that time than now, and it certainly skewed female statistics downward. It was common for average citizens to take great care in their hygiene (sanitation), Mediterranean diet (fish, figs, olive oil, wine, etc.), and exercise program (sports/gymnasium), although there was much more male trauma per capita than today, due to military service being virtually universal for citizens. This also biased the statistics for men downward. Diogenes Laertius (c. 250) gives the earliest (or at least one of the earliest) references about (plausible centenarian) longevity given by a scientist, the astronomer Hipparchus of Nicea (c. 185 – c. 120 B.C.), who, according to the doxographer, assured that the philosopher Democritus of Abdera (c. 470/460 – c. 370/360 B.C.) lived 109 years. All other accounts about Democritus given by the ancients appear to agree in the fact that the philosopher lived over 100 years. Such longevity would not be dramatically out of line with that of other ancient Greek philosophers thought to have lived beyond the age of 90 (e.g.: Xenophanes of Colophon, c. 570/565 – c. 475/470 B.C.; Pyrrho of Ellis, c. 360 - c. 270 B.C.; Eratosthenes of Cirene c. 285 – c. 190 B.C., etc.). The case of Democritus differs from the case of, for example, Epimenides of Crete (VII, VI centuries B.C.) who is said to have lived an implausible 154, 157 or 290 years, depending on the source.
The sixth dynasty Egyptian ruler Pepi II is believed by some Egyptologists to have lived to the age of 100 or more (c. 2278 BC - c. 2184 BC), as he ruled for 94 years. However this is under dispute, as others claim the date should actually be 64 years.
The Indian Sufi poet, Kabir (1398-1518?) is believed by some to have lived to an unnatural age of 120 while others believe that he lived for no more than 80 years.
Ultimately, there is no reason to believe that there could not have been a few individuals who were centenarians 2500 years ago, even if they were not commonplace.
As reported on the front cover of USA Today of August 24, 1999, The U.S. Census Bureau has forecast that the number of Americans aged 100 or older will increase by more than 22 times the 1990 estimate of 37,306. In October 2001, the US Census Bureau actually reported that there were 50,454 US centenarians (a more reasonable 35 percent increase) out of a total population of 281.4 million Americans. The Allstate insurance company reported that, in 2007, the Hallmark company sold approximately 85,000 "Happy 100th Birthday!" cards. But by 2050, "the number of US centenarians is expected to reach 834,000 and maybe even 1 million," said Dr. Robert Butler, President of the International Longevity Center in New York City.
From present data, the number of worldwide centenarians is around 450,000. However, if one considers only the total number of supercentenarians, this number falls dramatically to an estimated 300 to 450 worldwide, of which only approximately 80 are validated. Only one person, Jeanne Calment, has been indisputably proven to have lived for at least 120 years. Shigechiyo Izumi's claim of having reached 120 years is disputed. Despite the fact that there are a large number of pretenders from other countries, these claimants have never been rigorously validated by means of the sort of documentation that would be sufficient to prove their claim (birth certificates, baptismal certificates, marriage certificates, and so forth). However, record keeping was never rigorous before the age of data processing. Persons born at home in rural areas were considered fortunate if they had a family Bible to record their birthdate, let alone the correct spelling of the parents' names, their ages at the time, etc.
The Social Security Administration extended the life expectancy tables up to age 119 in 2005. In the course of the last four decades, the number of people reaching 100 has increased almost tenfold, so that now one in fifty women and one in two hundred men reach that age. This fact, in addition to the increase in birth and immigration of younger cohorts, leads to common errors in interpreting life expectancy.
Research carried out in Italy suggests that healthy centenarians have high levels of vitamin A and vitamin E and that this seems to be important in guaranteeing their extreme longevity. Other research contradicts this, however, and has found that these findings do not apply to centenarians from Sardinia, for whom other factors probably play a more important role. A preliminary study carried out in Poland showed that, in comparison with young healthy female adults, centenarians living in Upper Silesia had significantly higher red blood cell glutathione reductase and catalase activities and higher, although insignificantly, serum levels of vitamin E. Researchers in Denmark have also found that centenarians exhibit a high activity of glutathione reductase in red blood cells. In this study, those centenarians having the best cognitive and physical functional capacity tended to have the highest activity of this enzyme. Other research has found that people having parents who became centenarians have an increased number of naïve B-cells. It is well known that the children of parents who have a long life are also likely to reach a healthy age, but it is not known why.
|Country||Centenarians (year)||Centenarians (year)||Centenarians (year)||Centenarians (year)||Percent over 65||Rate Per Mln People|
|USA||50,454 (2000)||37,306 (1990)||-||-||13%||200.2|
|Japan||36,276 (2008)||32,295 (2007)||1,000 (1981)||153 (1963)||22.3%||284.0|
|England+Wales||9,000 (2007)||8,370 (2005)||7,100 (6-2002)||100 (1911)||16%||169.8|