Comment Much like AIDS ... (Score 1) 183
People die of cancer. stroke, heart attack, emphysema. and countless other disease, but aging isn't one of them.
With AIDS the HIV virus gradually destroys the immune system. Then some infection isn't successfully fought off. The immediate "cause of death" is the infection. But the underlying cause of death is the destruction of the immune system by HIV.
Similarly, with aging, a host of systems gradually fail, through a number of mechanisms, of which telomere-shortening is the underlying cause of most. Eventually one of these systems failures results a disease process (or failure to reverse a disease process), and that disease process causes death. The recorded "cause of death" is the particular disease process. But the underlying cause is the system failure from aging.
Take cancer: Accumulated errors in DNA replication, perhaps combined with a couple pre-errored codes inherited from the parents, result in a clone of cells that don't stop replicating when they should, and are able to evade the self-destruct mechanisms (including the hayflic. The accumulation of errors is one aspect of aging. The failure of the immune system to recognize, destroy, and clean out the clone of misprogrammed cells, more common in older people, is another.