But recent tests are showing there are more adult cases than previously thought.
"When someone is initially diagnosed with diabetes, when they're young we initially think it's type 1. And the symptoms of that are usually increased weight loss and we see the increased thirst and increase urination. So the symptoms of type 1 and type 2 are very similar," says certified diabetes educator Susan Pittman.
Medical history is the first clue a patient is at risk for type 1.
"What they're looking for is antibodies that are present in the body. In these, we know that in type 1 there's a genetic component and an environmental component. So what they're looking for is if the person who's genetically predispositioned for type 1 has been exposed to the environmental factors," Pittman says.
And finding those early indicators can make a big difference before the patient's health is at risk.
"Blood sugar can escalate, patients can go into what we call diabetic ketoacidosis which can lead to coma which is very very dangerous," Pittman says.