Race, Hair Color, Hair Type, and reaction to finasteride/minoxidil

[Warren Buffett]

Has anyone done a study on finasteride/minoxidil's sucess rates for specific races, hair colors or hair types? I am curious as to whether or not someone with thick curly hair fairs better than someone with straight thin hair. The same thing goes for race. Maybe i am way off base but i was curious as to what other people think on this matter.