Abstract
Aging is the accumulation of changes that increase the risk of death. Aging changes can be attributed to development, genetic defects, the environment, disease, and an inborn process: the aging process. The latter is the major risk factor for disease and death after age 28 in the developed countries. In these countries, average life expectancies at birth (ALE-B) now range from 76 to 79 years, 6-9 years less than the limit of ~85 years imposed by aging. Aging changes may be caused by free radical reactions. The extensive studies based on this possibility hold promise that the ALE-B can be extended to >85 years and the maximum life span increased.
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