Gerontology

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Gerontology (from Greek: γερο, gero, "old age"; and λόγος, logos, "speech" lit. "to talk about old age") is the study of the social, psychological, biological, political, economic, historical and other aspects of human aging. Gerontology, as a set of interdisciplinary sciences is distinguished from geriatrics, which is the branch of medicine that studies the diseases of old age. Most fields of gerontology recognize the distinction made in geriatric medicine between the acute illnesses and diseases, that affect people throughout the life cycle but from which people generally recover (or die) and [[chronic diseases] and conditions], many of which require long periods of time to develop and which consequently affect older people with greater frequency.

Gerontology includes these and other endeavors:

* studying physical, mental, and social changes in people as they age;
* investigating the aging process itself (biogerontology);
* investigating the effects of our aging population on society, including the fiscal effects of pensions, entitlements, life and health insurance, and retirement planning;
* applying this knowledge to policies and programs, including a macroscopic (i.e. government planning) and microscopic (i.e. running a nursing home) perspective.

The reasons for the rising interest in the study of aging are to be found in demographic changes that began silently around the start of the twentieth century. It was not until the 1940s, however, that pioneers like James Birren, Clark Tibbitts, Wilma Donahue, and others began organizing 'gerontology' into a recognized field of study. Recognizing that there were experts in many fields all dealing with the elderly, it became apparent that a national professional association of researchers and practitioners was needed. The Gerontological Society of America was founded 1945.

The multidisciplinary focus of gerontology means that there are a number of sub-fields, as well as associated fields such as psychology and sociology that also cross over into gerontology. However, that there is an overlap should not be taken as to construe that they are the same. For example, a psychologist may specialize in early adults (and not be a gerontologist) or specialize in older adults (and be a gerontologist).

The field of gerontology was developed relatively late, and as such often lacks the structural and institutional support needed (for example, relatively few universities offer a Ph.D. in gerontology). Yet the huge increase in the elderly population in the post-industrial Western nations has led to this becoming one of the most rapidly growing fields. As such, gerontology is currently a well-paying field for many in the West.

## Contents

* 1 Biogerontology
* 1.1 Notable biogerontologists
* 1.1.1 Notable biomedical gerontologists
* 1.1.2 Notable biogerotechnologists (business/applied)
* 1.1.3 Notable demographic gerontologists
* 1.1.4 Notable non-biomedical biogerontologists
* 2 Social gerontology
* 3 Life expectancy
* 4 Toward biogerontology
* 5 Academic resources
* 6 References

## Biogerontology[edit]

For more information, see: Life extension.

Biogerontology, is the subfield of gerontology dedicated to studying the biological processes involved in aging. Some have looked to develop theories of the aging process, such as telomere shortening, the free radical theory, and the like. Some skeptics have worked to show that aging is a biological process that we are far from being able to control. Conservative biogerontologists who have only an intellectual interest in the aging process, like Leonard Hayflick, have predicted that the human life expectancy numbers will top out at about 85 (88 for females, 82 for males).

Biomedical gerontology also known as experimental gerontology and life extension, is a sub discipline of biogerontology, that endeavors to slow, prevent, and even reverse aging in both humans and animals. Curing age-related diseases is one approach, and slowing down the underlying processes of aging is another. Most 'life extensionists' believe the human life span can be altered within the next century, if not sooner. 'Optimists' have predicted a changing human life span, though this has not yet been demonstrated.

Many biogerontologists take an intermediate position, emphasizing the study of the aging process as a means of mitigating aging-associated diseases, while denying that maximum life span can be altered (or denying that it is desirable to try).

### Notable biogerontologists[edit]

#### Notable biomedical gerontologists[edit]

* Ana Aslan
* L. Stephen Coles \- a key member of the Supercentenarian Research Foundation
* Aubrey de Grey \- originated the concept and theory of engineered negligible senescence
* Steven A. Garan
* Leonid Gavrilov \- suggested Reliability theory of aging and longevity
* Leonard Guarente \- Proposed that Sirtuins mediate the beneficial effects of caloric restriction [1]
* Thomas E. Johnson \- discovered long-lived mutants of C elegans
* Matt Kaeberlein \- discovered the anti-aging role of Sirtuins [2] and proposed that the  mammalian target of rapamycin  (mTOR) mediates the beneficial effects of caloric restriction [3]
* Brian Kennedy \- disproved the hypothesis that Sirtuins mediate the beneficial effects of caloric restriction[4] and proposed that the  mammalian target of rapamycin  (mTOR) mediates the beneficial effects of caloric restriction [5]
* Cynthia Kenyon \- quadrupled the lifespan of specimens of the small worm Caenorhabitis elegans by altering a single gene
* Durk Pearson
* Marios Kyriazis \- Proposed carnosine as a general anti-aging supplement, and disapproved the notion that cosmetics and beauty products form part of anti-aging medicine
* Suresh Rattan
* Michael R. Rose \-- bred long-lived fruit flies, a founder of evolutionary biogerontology
* David Sinclair \- Proposed that resveratrol slows aging and mimics caloric restriction by activating Sirtuins [6]
* Roy Walford (June 29, 1924 San Diego, California – April 27, 2004) - an early advocate of caloric restriction

#### Notable biogerotechnologists (business/applied)[edit]

* Robert Lanza
* Thomas Okarma
* Michael West

#### Notable demographic gerontologists[edit]

* Jay Olshansky \- a noted skeptic of life-extension claims
* Jean-Marie Robine \- validated the Jeanne Calment case
* James Vaupel \- lead the push for the internationalization of demographic data on the human life span

#### Notable non-biomedical biogerontologists[edit]

* Michael Fossel
* Leonard Hayflick (born 1928) - discovered the Hayflick limit
* Denham Harman (born 1916) - developed the free radical theory of aging
* Raymond Pearl (3 June 1879 - 17 November 1940)

## Social gerontology[edit]

Social gerontology is a multi-disciplinary sub-field that specializes in studying or working with older adults. For further information on this topic see this accompanying article.

## Life expectancy[edit]

One of the major demographic fallacies that the recent study of human aging in gerontology has cleared up is the notion that life expectancy was dramatically shorter in the past than at present. While there is no doubt that there have been major increases in life expectancy over the past century, until quite recently these were due almost exclusively to decreases in infant mortality. The view that modern humans in general live dramatically longer than earlier humans is seemingly made more plausible by earlier, and even more dramatic, increases in life expectancy (and comparable increases in height) that have, in fact, occurred in the past several millennia. Thus, it is not at all unusual to encounter suggestions that overall human life expectancy at the dawn of the agricultural revolution 10,000 BC was 14 years old, and later, during the Roman Empire rose only to 21 years old. All of this is largely a statistical anomaly; demographers do not actually compute individual life expectancy, but rather the average life expectancy of populations, and therein lies a world of difference. In reality, the dramatic quantitative increases in average life expectancy between 1900 and 2000 have been largely due to dramatic decreases in infant and childhood mortality. It wasn't so much that people, on the whole were living dramatically longer, as it was that vastly more people were surviving the first years of life.

There is a vast difference between average life expectancy statistics and the human life span. The Old Testament speaks of people living "three score and ten" as the fullness of life, suggesting that even several thousand years ago, adults who survived childhood may have expected to lived seventy years. A human population that normally lived only 14 years would be seriously on the verge of extinction. There is no evidence to suggest rapid evolution upward in the age of puberty within the last few thousand years. Thus, since sizeable proportions of 14 year olds would not even have reached sexual maturity, and, even if sexually mature at 10, would not have lived long enough to successful raise their children. Although a life span of 21 years would be more plausible from a reproductive standpoint, documentary evidence from the Roman Empire also largely refutes this notion: "Pliny the Elder" did not die at the ripe old age of 22!

## Toward biogerontology[edit]

Some early pioneers, notably Michel-Eugene Chevreul, who lived to be 102 in the 1880s, believed that human aging should be a science. The word gerontology was coined circa 1903.[7] However, prior to the 1980s, attention to issues of gerontology in medicine and biology was largely restricted to a few pioneer investigators. Then, pioneering research by Leonard Hayflick in the 1960s (showing that a cell line culture will only divide about 50 times) helped lead to a separate branch, biogerontology. It became apparent that simply 'treating' aging wasn't enough. Finding out about the aging process, and what could be done about it, became an issue.

The biogerontological field was also bolstered when research by Cynthia Kenyon and others demonstrated that life extension was possible in lower life forms such as fruit flies, worms, and yeast. So far, however, nothing more than incremental (marginal) increases in life span have been seen in any mammalian species.

Today, social gerontology remains the largest sector of the field, but the biogerontological side is seen as being the 'hot' side.[8] Indeed, some have said that social gerontologists look to the past; biogerontologists look to the future.

## Academic resources[edit]

* Journal of Applied Gerontology, ISSN: 1552-4523 (electronic) ISSN: 0733-4648 (paper), SAGE Publications
* Age and Aging, an international journal publishing refereed original articles on geriatric medicine and gerontology. Oxford University Press. 6 issues / 12 months. ASIN: B00006LAGZ ISSN:

## References[edit]

1. ↑ Guarente, L. and F. Picard, Calorie restriction--the SIR2 connection. Cell, 2005. 120(4): p. 473-82.
2. ↑ 1\. Kaeberlein, M., M. McVey, and L. Guarente, The SIR2/3/4 complex and SIR2 alone promote longevity in Saccharomyces cerevisiae by two different mechanisms. Genes Dev, 1999. 13(19): p. 2570-80.
3. ↑ Kaeberlein, M., et al., Regulation of yeast replicative life span by TOR and Sch9 in response to nutrients. Science, 2005. 310(5751): p. 1193-6.
4. ↑ Kaeberlein, M., et al., Sir2-independent life span extension by calorie restriction in yeast. PLoS Biol, 2004. 2(9): p. E296.
5. ↑ Kaeberlein, M., et al., Regulation of yeast replicative life span by TOR and Sch9 in response to nutrients. Science, 2005. 310(5751): p. 1193-6.
6. ↑ Howitz, K.T., et al., Small molecule activators of sirtuins extend Saccharomyces cerevisiae lifespan. Nature, 2003. 425(6954): p. 191-6.
7. ↑ Online Etymology Dictionary
8. ↑ Roy Walford and the immunologic theory of aging