I'm not sure if there has already been studies about this, but if there isn't, there should be.
I read somewhere that they are seeing a rise in young women with alopecia. (I used to have alopecia areata----it's now turned into universalis).
I have been on and off birth control (mostly on) for the past 14 years. I'm almost 30, and I started my first pack when I was 16.
I've wondered for a long time if there is a connection. After all, it's young women who usually take birth control!
It may be more correlation than causation, but I'm really curious.