Gerontology

Gerontology (from the Greek γέρων, geron, "old man" and -λογία, -logy, "study of"; coined by Ilya Ilyich Mechnikov in 1903) is the study of the social, psychological and biological aspects of aging. It is distinguished from geriatrics, which is the branch of medicine that studies the diseases of older adults. Gerontologists includes researchers and practitioners in the fields of biology, medicine, nursing, dentistry, social work, physical and occupational therapy, psychology, psychiatry, sociology, economics, political science, architecture, pharmacy, public health, housing and anthropology .

Gerontology encompasses the following:

• studying physical, mental, and social changes in people as they age
• investigating the aging(ageing), process itself (biogerontology)
• investigating the interface of normal ageing and age-related disease (geroscience)
• investigating the effects of an ageing population on society
• applying this knowledge to policies and programs, including the macroscopic (for example government planning) and microscopic (for example running a nursing home) perspectives.

The multidisciplinary nature of gerontology means that there are a number of sub-fields, as well as associated fields such as psychology and sociology that overlap with gerontology. Gerontologists view aging in terms of four distinct processes, chronological aging, biological aging, psychological aging, and social aging. . Chronological aging is the definition of aging based on a person's years lived from birth . Biological aging refers to the physical changes that reduce the efficiency of organ systems . Psychological aging includes the changes that occur in sensory and perceptual processes, cognitive abilities, adaptive capacity, and personality . Social aging refers to an individual's changing roles and relationships with family, friends, and other informal supports, productive roles and within organizations .

Aging Demographics

Rapid aging populations are expected worldwide. In 1900, there were 3.1 million people aged 65 years and older living in the United States. However, this population continued to grow throughout the twentieth century and reached 31.2, 35, and 40.3 million people in 1990, 2000, and 2010, respectively. Notably, in the United States, the "baby boomer" generation began to turn 65 in 2011. Recently, the population aged 65 years and older has grown at a faster rate than the total population in the United States. The total population increased by 9.7%, from 281.4 million to 308.7 million, between 2000 and 2010. However, the population aged 65 years and older increased by 15.1% during the same period. It has been estimated that 25% of the population in the United States and Canada will be aged 65 years and older by 2025. Moreover, by 2050, it is predicted that, for the first time in United States history, the number of individuals aged 60 years and older will be greater than the number of children aged 0 to 14 years. Those aged 85 years and older (oldest-old) are projected to increase from 5.3 million to 21 million by 2050. Adults aged 85-89 years constituted the greatest segment of the oldest-old in 1990, 2000, and 2010. However, the largest percentage point increase among the oldest-old occurred in the 90-94 year old age group, which increased from 25.0% in 1990 to 26.4% in 2010. With the rapid growth of the aging population, social work education and training specialized in older adults and practitioners interested in working with older adults are increasingly in demand In the last decade, geriatric social work education, practice, and research have received substantial support from foundations such as the John. A Hartford Foundation, Robert Wood Johnson Foundation, and Atlantic Philanthropies.

Gender Differences with Age

There has been a considerable disparity between the number of men and women in the older population in the United States. In both 2000 and 2010, women outnumbered men in the older population at every single year of age (e.g., 65 to 100 years and over). The sex ratio, which is a measure used to indicate the balance of males to females in a population, is calculated by taking the number of males divided by the number of females, and multiplying by 100. Therefore, the sex ratio is the number of males per 100 females. In 2010, there were 90.5 males per 100 females in the 65 year old population. However, this represented an increase from 1990 when there were 82.7 males per 100 females, and from 2000 when the sex ratio was 88.1. Although the gender-gap between men and women has narrowed, women continue to have a greater life expectancy and lower mortality rates at older ages relative to men. For example, the Census 2010 reported that there were approximately twice as many women as men living in the United States at 89 years of age (361,309 versus 176,689, respectively).

Geographic Distribution of Older Adults

The number and percentage of older adults living in the United States vary across the four different regions (Northeast, Midwest, West, and South) of the United States census. In 2010, the South contained the greatest number of people aged 65 years and older and 85 years and older. However, proportionately, the Northeast contains the largest percentage of adults aged 65 years and older (14.1%), followed by the Midwest (13.5%), the South (13.0%), and the West (11.9%). Relative to the Census 2000, all geographic regions demonstrated positive growth in the population of adults aged 65 years and older and 85 years and older. The most rapid growth in the population of adults aged 65 years and older was evident in the West (23.5%), which showed an increase from 6.9 million in 2000 to 8.5 million in 2010. Likewise, in the population aged 85 years and older, the West (42.8%) also showed the fastest growth and increased from 806,000 in 2000 to 1.2 million in 2010. It is worth highlighting that Rhode Island was the only state that experienced a reduction in the number of people aged 65 years and older, and declined from 152,402 in 2000 to 151,881 in 2010. Conversely, all states exhibited an increase in the population of adults aged 85 years and older from 2000 to 2010.

History of Gerontology

In the medieval Islamic world, several physicians wrote on issues related to Gerontology. Avicenna's The Canon of Medicine (1025) offered instruction for the care of the aged, including diet and remedies for issues including constipation. Arabic physician Ibn Al-Jazzar Al-Qayrawani (Algizar, c. 898-980) wrote on the medicine and health of the elderly. His scholarly work covers sleep disorders, forgetfulness, how to strengthen memory and causes of mortality Ishaq ibn Hunayn (died 910) also wrote on treatments for forgetfulness.

While the number of aged humans, and the maximum life span, tended to increase in every century since the 14th, society tended to consider caring for an elderly relative as a family issue. It was not until the coming of the Industrial Revolution that ideas shifted in favor of a societal care-system. Care homes for the aged emerged in the 19th century.

Some early pioneers, such as Michel Eugène Chevreul, who himself lived to be 102, believed that aging itself should be a science to be studied. The word "gerontology" was coined circa 1903 by Elie Metchnikoff.

It was not until the 1940s, however, that pioneers like James Birren began organizing gerontology into its own field. Recognizing that there were experts in many fields all dealing with the older population, it became apparent that a group like the Gerontological Society of America (founded in 1945) was needed. Two decades later, James Birren was appointed as the founding director of the first academic research center devoted exclusively to the study of aging, the Ethel Percy Andrus Gerontology Center at the University of Southern California. The Baltimore Longitudinal Studies of Aging began in 1958 in order to study physiological changes in healthy middle-aged and older men living in the community by testing them every two years on numerous physiological parameters . In 1967, the University of South Florida and the University of North Texas (formerly North Texas State University) received Older Americans Act training grants from the U.S. Administration on Aging to launch the nation's first degree programs in gerontology, at the master's level. In 1975, the University of Southern California's Leonard Davis School of Gerontology, with Birren as its founding dean, became the country's first school of gerontology within a university and, later, offered the first PhD in Gerontology degree. Since that time, a number of other universities have formed departments or schools of gerontology or aging studies.

More generally, gerontological education has flourished in the United States since 1967 and degrees at all academic levels are now offered by a number of colleges and universities. Several university-based centers on aging have been founded such as the Duke University Center on Aging, the University of Georgia Institute of Gerontology, the Center of Aging at the University of Chicago, and the Stanford Center on Longevity . Relatively few universities offer a PhD in gerontology. Currently, PhD programs in gerontology are available at the University of Kansas, University of Kentucky, University of Maryland, University of Massachusetts Boston, and the University of Southern California. The substantial increase in the aging population in post-industrial Western nations has led to this becoming one of the most rapidly growing fields.

From the 1950s to the 1970s, the field was mainly social and concerned with issues such as nursing homes and health care. However, 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 was not enough. Developing an understanding of the aging process, and what could be done about it, became an issue.

Biogerontology 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.

Biogerontology

Biogerontology is the sub-field of gerontology concerned with the biological processes of aging. It involves interdisciplinary research on biological aging's causes, effects, and mechanisms. Conservative biogerontologists such as Leonard Hayflick have predicted that the human life expectancy will peak at about 85 (88 for females, 82 for males), although the consensus now is that the numbers will continue to rise.

Biogerontologists usually work at research universities or laboratories. The majority of biogerontologists have a PhD, sometimes a MD.

The multidisciplinary focus of gerontology and biogerontology means that there are a number of sub-fields, ... (Biogerontology Net, retrieved by Dr.Robelyn Garcia, 2010)

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. Approaches include curing age-related diseases and slowing down the underlying processes of aging. Most "life extensionists" believe the human life span can be increased within the next century, if not sooner. Optimists such as Aubrey de Grey are of the opinion that the first person to live a thousand years has already been born. Some biogerontologists take an intermediate position, emphasizing the study of the aging process as a means of mitigating aging-associated diseases, while either claiming that maximum life span can not be altered or that it is undesirable to try.

As with biogerontology, geriatrics studies the biological causes and effects of aging. Both fields are considered by many scientists to be the most important frontiers in aging research.

Biological Theories of Aging

Theories of aging are numerous and no one theory has been accepted. There is a wide spectrum of the types of theories for the causes of aging with programmed theories on one extreme and error theories on the other. Regardless of the theory, a commonality is that as humans age, functions of the body decline.

Wear and Tear

Wear and Tear theories of aging suggest that as an individual ages, body parts such as cells and organs wear out from continued use. Wearing of the body can be attributable to internal or external causes that eventually lead to an accumulation insults that are not fully repaired. Due to these internal and external insults, cells lose their ability to regenerate, which ultimately leads to mechanical and chemical exhaustion. Some insults include chemicals in the air, food, or smoke. Other insults may be things such as viruses, trauma, free radicals, cross-linking, and high body temperature.

Genetic

Genetic theories of aging propose that aging is programmed within each individual's genes. According to this theory, genes dictate cellular longevity. Programmed cell death, or apoptosis is determined by a "biological clock" via genetic information in the nucleus of the cell. Over the course of normal development, these genes are expressed or repressed. Environmental factors and genetic mutations can influence gene expression and accelerate aging.

General Imbalance

General Imbalance theories of aging suggest that body systems, such as the endocrine, nervous, and immune systems, gradually decline and ultimately fail to function. The rate of failure varies system by system.

Accumulation

Accumulation theories of aging suggest that aging is bodily decline that results from an accumulation of elements. Elements can be foreign and introduced to the body from the environment. Other elements can be the natural result of cell metabolism. An example of an accumulation theory is the Free Radical Theory of Aging. According to this theory, byproducts of regular cell metabolism called free radicals interact with cellular components such as the cell membrane and DNA and cause irreversible damage.

Social Gerontology

Social gerontology is a multi-disciplinary sub-field that specializes in studying or working with older adults.

Social gerontologists may have degrees or training in social work, nursing, psychology, sociology, demography, gerontology, or other social science disciplines. Social gerontologists are responsible for educating, researching, and advancing the broader causes of older people.

Because issues of life span and life extension need numbers to quantify them, there is an overlap with demography. Those who study the demography of the human life span differ from those who study the social demographics of aging.

Social Work with Older Adults

Social work with older adults, known as geriatric social work practice, is considered to be both a macro and micro practice with individuals over the age of 60 or 65, their families and communities, aging related policy, and aging research. Geriatric social workers typically provide counseling, direct services, care coordination, community planning, and advocacy in an array of agencies and organizations including private practice, in home, neighborhoods, hospitals, senior congregate living, hospice/end of life care, senior centers, oncology centers and residential long term care facilities such as nursing facilities. At the macro level, geriatric social workers work within state departments of health, adult protective services, and at universities and colleges, as well as Administration on Aging offices on a federal level in the United States.

Social Theories of Aging

According to Dannefer, aging is an interactive process where the individual is affected by the environment while also influencing the environment in which he/she ages. Several theories of aging are developed to observed the aging process of older adults in society as well as how these processes are interpreted by men and women as they age.

Activity Theory

Activity theory was developed and elaborated by Cavan, Havinghurst, and Albrecht. According to this theory, older adults' self-concept depends on social interactions. In order for older adults to maintain morale in old age, substitutions must be made for lost roles. Examples of lost roles include retirement from a job or loss of a spouse.

Disengagement Theory

Disengagement theory was developed by Cumming and Henry. According to this theory, older adults and society engage in a mutual separation from each other. An example of mutual separation is retirement from the workforce. A key assumption of this theory is that older adults lose "ego-energy" and become increasingly self absorbed. Additionally, disengagement leads to higher morale maintenance than if older adults try to maintain social involvement. This theory is heavily criticized for having an escape clause. namely, that older adults who remain engaged in society are unsuccessful adjusters to old age.

Age Stratification Theory

According to this theory, older adults born during different time periods form cohorts that define "age strata". There are two differences among strata: Chronological age and Historical experience. This theory makes tow arguments. 1. Age is a mechanism for regulating behavior and as a result determines access to positions of power. 2. Birth cohorts play an influential role in the process of social change.

Life Course Theory

According to this theory, age occurs from birth to death. Aging involves social, psychological, and biological processes. Additionally, aging experiences are shaped by cohort historical factors.

Cumulative Advantage/Disadvantage Theory

According to this theory, inequalities have a tendency to become more pronounced throughout the aging process. A paradigm of this theory can be expressed in the adage "the rich get richer and the poor get poorer". Advantages and disadvantages in early life stages have a profound effect throughout the life span. However, advantages and disadvantages in middle adulthood have a direct influence on economic and health status in later life.

See also

• Academic journals on Gerontology
• Aging and memory
• Aging Portfolio
• Alliance for Aging Research
• American Aging Association
• American Federation for Aging Research
• Buck Institute for Age Research
• Elderly care

• Gerontology Research Group
• Institute for Geriatric Social Work
• Life Extension
• List of life extension topics
• Medical Mobile and Columba
• Methuselah Mouse Prize
• National Institute on Aging

• Nurses' Health Study
• Oldest people
• Retirement
• Silver Alert
• Telemedicine
• The Gerontological Society of America
• Young Foundation

References

17. Macieira-Coelho A., (2003) Biology of Aging, Progress in Molecular and Subcellular Biology, vol. 30, Springer-Verlag Berlin Heidelberg New York, ISSN 0079-6484, ISBN 3-540-43827-0.