Aging may perhaps play a role, but it can't be the only thing. Many bodybuilders make it into their 40s without any real symptoms of Palumbism. Also, some guys in the 30s have displayed symptoms- Palumbo himself, Kovacs, Kamali
Palumboism is likely caused by a combination of the following: androgen recepter burnout so AAS is no longer as effective, GH and 'slin abuse, aging, and a genetic predisposition.
It's downright comical how the gut keeps growing while the limbs and chest atrophy, the obliques and ribcage form a big mishapen "O", and the skin becomes brittle, all while a 30-something looks like he's in his 50's.