Longevity

The word longevity is sometimes used as a synonym for "life expectancy" in demography. However, this is not the most popular or accepted definition. [ [http://www.answers.com/topic/longevity?cat=health. longevity: Definition and Much More from Answers.com ] ] For the general public as well as writers, the word generally connotes 'long life', especially when it concerns someone or something lasting longer than expected (an 'ancient tree', for example).

Reflections on longevity have usually gone beyond acknowledging the basic shortness of human life and have included thinking about methods to extend life. Longevity has been a topic not only for the scientific community but also for writers of travel, science fiction and utopian novels. There are many difficulties in authenticating the longest human lifespan ever, due to inaccurate birth statistics; though fiction, legend, and mythology have proposed or claimed vastly longer lifespans in the past or future and longevity myths frequently allege them to exist in the present.

A life annuity is a form of longevity insurance.

History

Longevity according to the psalms of the Bible was estimated on average to be "threescore and ten", that is 70 years, and "by reason of strength be extended to fourscore", that is 80 years. [Holly Bible, King James Version, Psalm 90:10] In addition, Solon, the famous lawgiver of Ancient Greece, in his dialogue with Croesus stated 70 as the allotted length of life for man. fact|date=July 2008 The longest living person as recorded in the Old Testament was Methuselah, who was said to have lived nearly a millennium.

There are many organizations dedicated to exploring the causes behind aging, ways to prevent aging, and ways to reverse aging. Despite the fact that it is human nature not to wish to surrender to old age and death, a few organizations are against antiaging because they believe it sacrifices the best interests of the new generation and/or that it is unnatural and/or unethical. Others are dedicated to it, seeing it as a form of transhumanism and the pursuit of immortality. Even among those who do not wish for eternal life, longevity may be desired to experience more of life or to provide a greater contribution to humanity.

A remarkable statement mentioned by Diogenes Laertius (c. 250) is 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 given by the ancients about the age of Democritus appear to, without giving any specific age, agree on the fact that the philosopher lived over 100 years. This is a possibility that turns out to be likely, given the fact that many ancient Greek philosophers are thought to have lived over 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.) and because of the difference that the case of Democritus evidences from the case of, for example, Epimenides of Crete (VII, VI centuries B.C.), who is said to have lived 154, 157 or 290 years, as has been said about countless elders even during the last centuries as well as in the present time. These cases are not verifiable by modern means.

Present life expectancies around the world

Various factors contribute to an individual's longevity. Significant factors in life expectancy include gender, genetics, access to health care, hygiene, diet and nutrition, exercise, lifestyle, and crime rates. Below is a list of life expectancies in different types of countries:CIA World Fact Book]
*First World: . . . 77-83 years (e.g. Canada: 80.1 years, 2005 est)
*Third World:. . . 35-60 years (e.g. Mozambique: 40.3 years, 2005 est)

Population longevities can be seen as increasing due to increases in life expectancies around the world: [CIA World Fact Book 2002] Fact|date=January 2008
*Spain:. . . . . 81.02 years in 2002, 82.31 years in 2005Fact|date=January 2008
*Australia: . . 80 years in 2002, 80.39 years in 2005Fact|date=January 2008
*Italy:. . . . . . 79.25 years in 2002, 79.68 years in 2005 Fact|date=January 2008
*France: . . . .79.05 years in 2002, 79.60 years in 2005Fact|date=January 2008
*Germany: . . 77.78 years in 2002, 78.65 years in 2005Fact|date=January 2008
*UK: . . . . . . 77.99 years in 2002, 78.4 years in 2005Fact|date=January 2008
*USA: . . . . . 77.4 years in 2002, 77.7 years in 2005Fact|date=January 2008

The current validated longevity records can be found in the list of supercentenarians. Notable individuals include:
*Jeanne Calment (1875-1997, 122 years and 164 days) — the oldest person in history whose age has been verified by modern documentation. This defines the human lifespan, which is set by the oldest documented individual who ever lived.
*Shigechiyo Izumi (1865-1986, 120 years 237 days, disputed) — the oldest male ever recognized by the Guinness Book of World Records; this is widely questioned by scholars, who believe that conflation of dates has occurred and this has compromised the authenticity of Izumi's age.
*Christian Mortensen (1882-1998, 115 years 252 days) — the oldest male widely accepted by scholars.

Exceptions: Populations from developing world with high life expectancy

Some populations have reputation ["The Anti-Aging Plan: Strategies and Recipes for Extending Your Healthy Years" by Roy Walford (page 27)] [ [The Okinawaprogram: Learn the secrets to healthy longevity by Willcox, Willcox and Suzuki (page 3)] ] [Long lived populations: Extreme old age. J Am Geriatr Soc 30:485-87] of producing unusual number of individuals with exceptionally high ages, for example:
* Okinawans,
* people from the mountains of Pakistan the Hunza,
* the inhabitants from the high mountain valley of Vilcabamba in South America,
* inhabitants of some regions in the Caucasus mountains.

Religion

The Bible contains many accounts of long-lived humans, the oldest being Methuselah living to be 969 years old (bibleref|Genesis|5:27). Today some maintain that the unusually high longevity of Biblical patriarchs are the result of an error in translation: lunar cycles were mistaken for the solar ones, and that the actual ages being described would have been 12.4 times less (a lunar cycle being 29.5 days). This makes Methuselah's age only 78. This rationalization, however, seems doubtful too since patriarchs such as Mahalalel (bibleref|Genesis|5:15) and Enoch (bibleref|Genesis|5:21) were said to have become fathers after 65 "years". If the lunar cycle claim were accepted this would translate to an age of about 5 years and 3 months.

One claim of Christian scholars Who|date=October 2007 is that the life span of humans has changed; that originally man was to have everlasting life, but due to man's sin, God progressively shortened man's life in the "four falls of mankind" — first to less than 1000 years, then to under 500, 200, and eventually 120 years. After those long living people died around the time of the Biblical Flood, God decided that humans would not be permitted to live more than 120 years (bibleref|Genesis|6:3) However, since later biblical figures (and more recent people) such as Sarah lived for longer than that, 120 years should be considered the "usual" upper limit to man's lifespan. Some individuals can live slightly longer than that.

It has been hypothesized Who|date=October 2007 that there is a trade-off between cancerous tumor suppression and tissue repair capacity, and that by lengthening telomeres we might slow aging and in exchange increase vulnerability to cancer (Weinstein and Ciszek, 2002). Experimentation with telomeres on worms has yielded increased worm life spans by about 20% (Joeng et al., 2004).Even if further study shows that telomeres specifically are not tied to aging, the concept that some sort of DNA damage can cause genetically accelerated aging cannot be abandoned, thus providing a rational explanation for longevity and a subsequent reduction of longevity post-flood.

Many cultures like the Sumerians and Indus Valley also document groups of people who have lived for hundreds of years.

Furthermore, starting with reformers John Calvin and Martin Luther, an alternative explanation has arisen: 120 years would not refer to man's lifespan but to the amount of time left before the flood.

A more commonly accepted explanation Who|date=October 2007 is that such stories are longevity myths; age exaggeration tends to be greater in "mythical" periods in many cultures; the early emperors of Japan or China often ruled for more than a century, according to tradition. With the advent of modern accountable record-keeping, age claims fell to realistic levels. Even later in the Bible King David died at 70 years; other kings in their 30s, 40s, and 50s.

Future

The mainstream view on the future of longevity, such as the US Census Bureau, is that life expectancy in the United States will be in the mid 80s by 2050 (up from 77.85 in 2006) and will top out eventually in the low 90s, barring major scientific advances that can change the rate of human aging itself, as opposed to merely treating the effects of aging as is done today. The Census Bureau also predicted that the United States would have 5.3 million people aged over 100 in 2100.Fact|date=February 2008

Recent increases in the rates of lifestyle diseases, such as obesity, diabetes, hypertension, and heart disease, may however drastically slow or reverse this trend toward increasing life expectancy in the developed world.

Oeppen and Vaupel (see Science:1029, 2002) have observed that since 1840 record life expectancy has risen linearly for men and women, albeit more slowly for men. For women the increase has been almost three months per year. In light of steady increase, without any sign of limitation, the suggestion that life expectancy will top out must be treated with caution. Oeppen and Vaupel observe that experts who assert that "life expectancy is approaching a ceiling ... have repeatedly been proven wrong." It is thought that life expectancy for women has increased more dramatically due to the considerable advances in medicine related to childbirth.

Some argue that molecular nanotechnology will greatly extend human lifespans. If the rate of increase of lifespan can be raised with these technologies to a level of not three months per year, but twelve months per year, we will have achieved effective immortality. This is the goal of radical life extension.

Non-human biological longevity

Living:
*Methuselah — 4,800-year-old bristlecone pine in the White Mountains of California, the oldest currently living organism known.
*Cheeta — a 76-year-old chimpanzee, the oldest chimpanzee known.Dead:
* A bristlecone pine nicknamed "Prometheus", felled in the Great Basin National Park in Nevada in 1964, found to be about 4900 years old, is the longest-lived single organism known. [ [http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/1998/08/23/SC72173.DTL Carl Hall, "Staying Alive", "San Francisco Chronicle", 23 August 1998] ]
* A quahog clam ("Arctica islandica"), dredged from off the coast of Iceland in 2007, was found to be from 400 to 410 years old, the oldest animal documented. Other clams of the species have been recorded as living up to 374 years. [ [http://www.bangor.ac.uk/news/full.php.en?Id=382 Bangor University: 400 year old Clam Found] (retrieved 29 October 2007) [http://news.bbc.co.uk/2/hi/science/nature/7066389.stm BBC News: Ming the clam is 'oldest animal'] (retrieved 29 October 2007)]
* Tu'i Malila, a radiated tortoise presented to the Tongan royal family by Captain Cook, lived for over 185 years. It is the oldest documented reptile. Adwaitya, an Aldabra Giant Tortoise, may have lived for up to 250 years.
* A Bowhead Whale killed in a hunt was found to be approximately 211 years old (possibly up to 245 years old), the longest lived mammal known. [ [http://www.gi.alaska.edu/ScienceForum/ASF15/1529.html Rozell (2001) "Bowhead Whales May Be the World's Oldest Mammals", Alaska Science Forum, Article 1529] (retrieved 29 October 2007)]
* "Lamellibrachia luymesi", a deep-sea cold-seep tubeworm, is estimated to reach ages of over 250 years based on a model of its growth rates.Fact|date=February 2007
* Hanako (Koi Fish) was the longest-lived vertebrate ever recorded at 215 years.

ee also

* Actuarial Science
* Biodemography
* Biodemography of human longevity
* Calorie restriction
* List of centenarians
* DNA damage theory of aging
* Hayflick limit
* Indefinite lifespan
* Life extension
* Longevity claims
* Lloyd Demetrius
* Maximum life span
* Mitohormesis
* Oldest viable seed
* Reliability theory of aging and longevity
* Resveratrol
* Senescence (aging)
* Strategies for Engineered Negligible Senescence (SENS)

Scientific books on longevity

* Leonid A. Gavrilov & Natalia S. Gavrilova (1991), "The Biology of Life Span: A Quantitative Approach". New York: Harwood Academic Publisher, ISBN
* John Robbins' [http://www.healthyat100.org "Healthy at 100"] garners evidence from many scientific sources to account for the extraordinary longevity of Abkhasians in the Caucasus, Vilcabambans in the Andes, Hunzas in Central Asia, and Okinawans.
* Beyond The 120-Year Diet, by Roy L. Walford, M.D.
* Forever Young: A Cultural History of Longevity from Antiquity to the Present Door Lucian Boia,2004 ISBN 1861891547

References

External links

* [http://www.antiagesystem.com/report.htm]
* [http://www.mfoundation.org/ The Methuselah Foundation]
* [http://www.afar.org American Federation for Aging Research]
* [http://www.whyweage.com Why We Age - A Comprehensive Anti-ageing and Longevity Resource]
* [http://www.agingresearch.org/longevitydividend/overview.cfm Alliance for Aging Research]
* [http://longevity-science.blogspot.com/2007/02/new-books.html New Books on Aging and Longevity Studies]
* [http://knowledge.allianz.com/en/special/aging_populations.html Longevity and Pensions] , Allianz Knowledge Site, February 2008
* [http://www.worldhealth.net American Academy of Anti-Aging Medicine]
* [http://www.thelongevityproject.com/ The Longevity Project]
* [http://www.ilcusa.org International Longevity Center]
* [http://www.okicent.org The Okinawa Centenarian Study]
* [http://www.senescence.info/nature.html Longevity and Aging of Animals]
* [http://longevity-science.org/ Longevity Science]
* [http://www.benbest.com/lifeext/aging.html Mechanisms of Aging]
* [http://www.gen.cam.ac.uk/sens/ Strategies for Engineered Negligible Senescence (SENS)]
* [http://www.calorierestriction.org The Calorie Restriction Society]
* [http://www7.nationalgeographic.com/ngm/0511/feature1/ The Secrets of Long Life (National Geographic magazine)]
* [http://www.longevity.fr/ Longevity event]
* [http://longevity-international.com/ International Research Centre for Healthy Ageing & Longevity (IRCHAL)]
* See U.S. Life Expectancy Longest Ever [http://www.time.com/time/nation/article/0,8599,1661268,00.html] on Time.com (a division of Time Magazine)