Aspergers and bedwetting?

Is there any coralation between the two? I know I was very late to stop bedwetting (and sometimes still do, maybe twice a year), and I was talking to a friend of mine who also has AS and he said he wet the bed until he was 10, and still has "accidents".

Has there been any studies on the subject that I can read or anything? What would cause so many Aspies to be bedwetters (As I know eight people in my AS groop that also have the issue)?