Has it been determined that sugar causes aging?

No not true: Aging is natural and we have not found any good medical solution to prevent or slow down aging, other than caloric restriction, which, in animals, does slow down the aging process somewhat.

Yes, sugar does age.: Sugar causes cross-linking of collagen and elastin. Sugars attach to adjacent collagen chains which are elastic in formation by hydrogen bonds between hydroxyproline and hydroxylysine. These are replaced by irreversible covalent bonds. This is used medically (prolotherapy), but throughout the body-it is harmful. Skin because less elastic\as do joints and blood vessels. Sugar ages!