24. Aging Increases Disease Vulnerability, and Disease Can be Viewed as Localized Accelerated Aging

Aging is not a disease: diseases are specific pathological states, but aging is a process that increases incidence and vulnerability to diseases (51). On the other hand, chronic disease may be viewed as a state of localized accelerated aging of a particular organ or system (or a suborgan or subsystem) (52). Such a state is not just more aged but is also altered, as it interacts with other organismal systems with lower biological age and may have disease-specific etiologies. One may say that there are no chronic diseases, only more aged/altered systems within an organism that over time lead to pathological states that we call diseases. This paradigm unites aging and disease, but within the framework of aging. Calling aging a disease can be useful for mobilizing interventions and regulatory avenues as both diseases and aging can be treatable conditions, but it also risks conceptual confusion, especially when it implies a single etiology or a single drug cure. Interventions can be judged by whether they delay, slow, or reduce deleteriome burden and functional decline at the level of the whole organism (in the case of aging) or system/ subsystem (in the case of disease).