Well the website page
http://www.pilotswithdiabetes.com/pages/usa.html was written by Douglas Cairns whom has flown himself around the world while being a type 1 diabetic
The American Diabetic Association:
I. Restrictions on medical certification:
A. Individuals may be issued only a third-class airman medical certificate.
B. Individuals may exercise only the privileges of a student, recreational, or private pilot certificate.
C. Individuals are prohibited from operating an aircraft as a required crewmember on any flight outside the airspace of the United States of America.
http://www.diabetes.org/advocacy-and...a_protocol.jsp