The exact cause of type 2 diabetes is not known. However, experts believe the disease develops in children the same way it does in adults: the body does not produce enough of the hormone insulin, or it cannot correctly use the insulin available (insulin resistance). Either or both of these conditions lead to excess sugar (glucose) in the blood.

Insulin resistance

Insulin resistance occurs when the body's cells do not correctly use insulin, which helps control the amount of glucose in the blood. The body then needs more insulin to control blood sugar levels. The pancreas produces more insulin to try to keep blood sugar levels normal. If it cannot produce enough insulin, blood sugar rises, and diabetes may develop.

Factors that affect the body's resistance to insulin in childhood include:

• Developmental stage. Insulin resistance normally increases about 30% during puberty, probably because of the effects of growth hormone.¹
• Sex. Girls seem to develop more resistance to insulin than boys.
• Race. The body's resistance to insulin is about 30% higher in African-American teens than in white teens.²
• Body composition. Insulin resistance increases as the amount of fat around the waist increases.
• Activity. Exercise may improve how the body's cells use insulin and get the sugar they need.

Too little insulin

Normally, the pancreas produces more insulin than usual during puberty to support the rapid growth of the child. If the body cannot produce enough insulin to meet its needs, diabetes develops. Over time, the pancreas may produce less and less insulin, making the diabetes worse.