Is Old Age a Disease or Just Another of Life’s Stages?

Dr. Clarfield is the Chief of Geriatrics, Soroka Hospital Centre, Professor, Faculty of Medicine, Ben Gurion University of the Negev, Beersheva, Israel. Professor (Adjunct), Division of Geriatric Medicine, McGill University and Jewish General Hospital, Montreal, QC, Canada.

Have you ever heard of the wonderful one-hoss shay.
That was built in such a logical way.
It ran a hundred years to a day.
And then, of a sudden, it-ah, but stay.
I'll tell you what happened without delay.
Scaring the parson into fits.
Frightening people out of their wits,
Have you ever heard of that, I say?

Oliver Wendell Holmes

My own grandfather died when he was over 100 years old. Why? We don't know because, for religious reasons, no autopsy was performed. Even if it had been, what might it have shown? Possibly a Whitmore stage A or B carcinoma of the prostate, maybe a tumour in the cecum, perhaps the scars of previous myocardial infarcts, but very likely nothing that a pathologist could confidently have labeled as the cause of death.

So why do old people die? Is aging a disease or is it simply a normal life stage? Or, as Crapo and Fries have so elegantly described in their book "Vitality and Aging" (from which the above quote was lifted), is it simply the final disintegration of the old buggy?

In order to come to some understanding as to what aging actually comprises, it might be helpful to examine what pertains in other mammalian species.