Aging is the prime disease that causes all other diseases in life. Aging falls into population and individual levels.
Human individual aging creates dementia, cardiac disorder, and vascular diseases, and can cause declining metal capacities, physical functions, and social skills by oxidative stress with O2-, H2O2, and -OH in cellular process. Human population aging is a world wide issue, which is the cause of workforce reduction and tax increase in the aging society.
The exact biological mechanism of aging is unclear. Currently there are two theories. First is generally known damage concept, whereby the accumulation of DNA point mutations may cause biological systems to fail. Second is programmed aging concept, whereby DNA telomere shortening may cause aging.