What's the dance population you are asking about?
If you're looking at top professional dancers, most of them are in their twenties or thirties. So it's early for baldness to show up.
If you are looking at the general social dance population, my experience is that they have about the same rate of baldness as anyone else.
There's nothing special dancers losing their hair do. If they want to do something about it, they have the same options anyone else does--hair implants, toupees, etc.