Kevin has a very good response. I'd like to echo that both can be treated, albeit by different treatments. A person of any age can be diagnosed with either type 1 or type 2, but type 1 is predominently found in kids, hence the name.
All very good questions. First some definitions.
Type 1 Diabetes (also known as Juvenile Diabetes) is when your pancreas fails and no longer produces any Insulin.
Type 2 Diabetes is when your pancreas still produces Insulin but your body does not use it as effectively as it should.
For this reason Type 1 is considered more serious but both are treatable and controlable so that the person may live a relatively or almost completely normal life. It is always possible to go from Type 2 diabtes to Type 1 Diabetes but never the reverse. Many times a Type 2 Diabetic will be treated as a Type 1 (on the same medications etc) but will not actually BE a Type 1. Reason being the treatments for a Type 1 are also effective on a Type 2 if that severity of treatment is needed. It is believed that Type 2 can be prevented or delayed in its onset by proper diet and exercise just like you would do if you actually had Type 2. As far as I know there is no way to prevent Type 1.
Thank you very much! You have always been very prompt.
When will type 2 become type 1? Is that when sugar level is high for many years?
Basically that is completely unknown. But it is believed that if you maintain good levels it will extend Type 2 duration before Type 1. But even with bad levels it is not certain that you will become a Type 1. You only become a Type 1 when you panncreas fails completely. Some believe that if you over work it with bad levels it will fail sooner others believe that it is just not as good as it should be and that will not change. I think that both are true. But the short answer is that there is no way to predict the answer. Better care certainly can not hurt !!! :)