Ageing (British English) or aging (American English) is the process of becoming older. It represents the accumulation of changes in a person over time. In humans, aging refers to a multidimensional process of physical, psychological, and social change. Population aging is the increase in the number and proportion of older people in society. Population aging has three possible causes: migration, longer life expectancy (decreased death rate) and decreased birth rate.
What is an Aging Associated Disease
An aging associated disease is a disease that is seen with increasing frequency with increasing senescence. Age associated diseases are to be distinguished from the aging process itself because all adult humans age, but not all adult humans experience all age-associated diseases.
Examples of aging-associated diseases are cardiovascular disease, cancer, arthritis, dementia, cataract, osteoporosis, diabetes, hypertension and Alzheimer's disease. The incidence of all of these diseases increases rapidly with aging (increases exponentially with age, in the case of cancer).
Aging (senescence) increases vulnerability to age-associated diseases, whereas genetics determines vulnerability or resistance between species and individuals within species.
Some consequences of aging are age-related changes in vision, hearing, muscular strength, bone strength, immunity, and nerve function. Glaucoma and cataracts are ocular problems associated with aging that can be treated to restore failing vision in older people. Hearing loss is often noticeable by age 50, and the range of sounds heard decreases. Muscle mass and nervous system efficiency decrease, causing slower reflex times and less physical strength, and the immune system weakens, making older people more susceptible to infections.
The constant and rapid increase of life expectancy in western countries is associated with a major aging of our populations. In these conditions, we can expect an epidemic progression of most chronic diseases, especially cardiovascular, neurodegenerative and metabolic disorders, the main causes of death in the world.
Increasing life expectancy is concomitant with increased risk of aging-associated diseases, e.g. obesity, diabetes, atherosclerosis, cancer, and neurodegenerative diseases. These diseases pose enormous challenges both for individuals and societies in terms of life quality and economic burden, thereby necessitating an urgent need for aging societies to address these health concerns.
By 2030, the proportion of the U.S. population aged 65 and older will double to about 71 million older adults, or one in every five Americans. The far-reaching implications of the increasing number of older Americans and their growing diversity will include unprecedented demands on public health, aging services, and the nation's health care system.
Much of the illness, disability, and death associated with chronic disease is avoidable through known prevention measures. Key measures include practicing a healthy lifestyle (e.g., regular physical activity, healthy eating, and avoiding tobacco use) and the use of early detection practices (e.g., screening for breast, cervical, and colorectal cancers, diabetes and its complications, and depression).
Studies have profound implications for aging research and could revolutionize approaches for prevention and treatment of aging-associated diseases. To be able to effectively treat diseases, there must first be a thorough understanding of the mechanisms underlying them.
Aging and longevity are determined by a complex mixture of environmental and genetic factors. The genetic aspect has been demonstrated in studies of centenarians, and in model organisms where single-gene mutations have been shown to dramatically increase lifespan. These genes have homologues in the mammalian genome, making them useful both in studying aging and in identifying potential targets for interventions which increase lifespan. These genes also increase lifespan in mice, and in some cases have been shown to associate with human longevity. Diet (specifically, caloric restriction) has been shown to substantially affect lifespan, including delay or prevention of many age-related diseases.
Of the roughly 150,000 people who die each day across the globe, about two thirds,100,000 per day, die of age-related causes.