It does seem to be the more ... voluptuous, zaftig, ummm ... rounder cats that tend to have this trouble too. Apparently the slimmer cats have an easier time grooming themselves back there and we humans don't see the dandruff as much.

Livvy, my dimpled darling (dumplinged darling?), had a bit of a problem when she came to me -- she'd been used to a cheaper brand of cat food. The vet recommended a vitamin mineral supplement for her food that would add essential oils faster. Unfortunately she hated the stuff. (And it was expensive, too, which added to my irritation with the whole thing...)