GH does not cause diabetes. I know what you mean, but here is the clarification:
In some people, GH therapy can elevate blood sugar, which is completely reversible on stopping the drug. At replacement dosages (for older people who are deficient), they majority don't get a significant or worrisome elevation in blood sugar and its not enough to satisfy lab thresholds for diabetes. If they are on a low glycemic index diet, watching their carbs and exercising 95% do just fine. This tends to be more of a temporary response too...after a period of 6 months, significant blood sugar elevation is rare.
Diabetes type 1 is an autoimmune condition that your born with. DM type 2 is usually related to obesity, nutritional/exercise habits, insulin resistance and some effect with genetics.