The body's immune system destroys the cells in the pancreas that make insulin. In time, the pancreas stops making insulin. Without insulin, cells can't absorb sugar (glucose), which they need to produce energy.

The body isn't able to use insulin the right way. This is called insulin resistance. As type 2 diabetes gets worse, the pancreas may make less and less insulin. This is called insulin deficiency.

Symptoms usually start in childhood or young adulthood.

It can develop at any age. It's usually discovered in adulthood. But the number of children with type 2 diabetes is rising.

People often seek medical help because they are seriously ill from sudden symptoms of high blood sugar.

People may not have symptoms before diagnosis.

Episodes of low blood sugar level (hypoglycemia) are common.

There are no episodes of low blood sugar level, unless the person is taking insulin or certain diabetes medicines.

Type 1 accounts for 5 to 10 out of 100 people who have diabetes.

Type 2 accounts for the vast majority of people who have diabetes—90 to 95 out of 100 people.

It can't be prevented.

It can be prevented or delayed with a healthy lifestyle. This includes staying at a healthy weight, eating sensibly, and exercising regularly.