Yes, old age
I can only presume
you didn't see the note.

Contrary to the traditional way
in which we believe this transformation
to be incremental
old age does in fact arrive
on one particular day
and all at once.

Oh, the hair may have gone grey already
and the joints long ache
but typically they arrange
for some kind of set-back
or passing illness and then
while you're distracted
they insert it in
the old age.

Precisely how this is done
is a closely-guarded matter
but it's assumed
(by friends in the resistance)
to be some kind of perpetual
motion machine set in reverse
(probably biologically administered)
which just runs you out
in an accelerating manner.

There are some who think it's introduced
directly via the brain
(either surgically or chemically
depending on their opportunity).

This notion is gaining more traction
as it would seem the most expedient
or reliable method to have people
essentially self-terminate
not in a suicidal manner
(although this has often been observed),
but more in the way of the subjects
(us, it happens to almost all of us)
generally 'giving up the ghost'.

However they're getting it done
there's no question it's devilishly effective.
I would advise you to keep an eye out.