Not long ago I was diagnosed as a "quasi-patient" pertaining to diabetes, so since then I have concerned myself with the cause and effect of the "disease".  This week when I sent my wife to a clinic, I found a pamphlet about diabetes on the table in waiting parlor. (the waiting room is shared by a chropractor and a specialist in endocrinology/metabolism)  The pamphlet gives a clear and concise description on the cause of diabetes which is the most easy-to-be-understood one I have ever seen.  Hereby I quote the description as below: 

Sugar (glucose葡萄糖) comes from food and your liver(肝臟), and goes to your bloodstream.  Your cells use sugar for energy. Insulin(胰島素) helps sugar get from your blood into your cells.  Insulin is a hormone made in your pancreas(胰腺). It acts as a key and attaches to cells so they open and let sugar inside.  Without the right amount of insulin, theres too much sugar in your blood.  This causes damage to your blood vessels and nerves.  With type 1 diabetes, your body doesnt make insulin.  With type 2 diabetes, your body doesnt make enough insulin or it doesnt use insulin like it should.  When you were first diagnosed with diabetes, you may have had symptoms of high blood sugar.  Once you begin treatment, youll need to watch out for low blood sugar as well.

Is it a succinct answer to the question that most diabetes patients are often asking?  FYI, some linguists argue that English is more capable of expounding the statements of science and law than Chinese is.  The argument seems somewhat convincing to me, though I am not quite sure about it. 

P.S. I think Chinese medical circle should work out a better translation for diabetes.  "糖尿病" sounds a little bit nasty.