The firm distinction made between aging and age-related disease is a modern phenomenon, a product of the way in which the regulation of medical research and development has progressed. It wasn't so very long ago, considered in the grand scheme of things, that much of dementia and cardiovascular disease were thought parts of aging, prior to the ability to accurately map and categorize specific biological manifestations of aging. Present regulatory systems are set up to approve (a) the existence of clearly defined and bounded medical conditions based more on their biochemistry than their epidemiology, and (b) treatments narrowly applied to one approved condition. The result is a slow slicing of aging into a potentially endless series of named conditions, as each small piece of the enormously complex end state of decline is defined and given a name. This implicitly favors the poor strategy of trying to control narrow parts of the complicated end stage of disease, pretending they are isolated when in fact they are not, and makes it harder to pursue the much better strategies of either prevention or ways to repair and reverse the root causes of aging.

Aging and age-related disease are clearly not distinct from one another. Aging is just a collection of countless age-related diseases, the few defined and the many not yet defined. Age-related diseases are just arbitrary lines drawn around parts of aging. Looking at it a different way, an age-related disease is an aspect of aging that has progressed far enough to be unbearable. Aging and age-related disease are caused by the same underlying mechanisms - the cell and tissue damage outlined in the SENS research proposals.

Is aging as a whole a disease? Can we just draw a line around the whole thing? This question has been asked ever more frequently of late. It is trivial semantics - except that regulators will not let a treatment for aging progress to the clinic unless they agree that aging is a disease by their formal definitions. Which they currently do not. Absent a defined path to the clinic, research funding for efforts to treat aging as a medical condition is much harder to obtain than would otherwise be the case. The whole development pipeline suffers, all the way back to fundamental science in this part of the field. It has required philanthropy and advocacy and non-profit organizations dedicated to aging to make any meaningful progress since the turn of the century. Now that it is becoming plausible to effectively reverse some of the causes of aging, such as via senolytic therapies to destroy senescent cells, it becomes ever more important that this ridiculous situation is resolved in a way that allows funding to flow and therapies to reach the clinic.

The Continuum of Aging and Age-Related Diseases: Common Mechanisms but Different Rates