Diabetes mellitus occurs when specialized cells of the pancreas (a gland behind the stomach) do not produce adequate amounts of the hormone insulin. Insulin permits the body to process proteins, fat, and sugars in food to make body tissues, produce energy, and store energy. In people without diabetes, insulin is produced as needed to process food. But people with diabetes have a reduced supply of insulin or none at all.
Type 1 Diabetes
Type 1 diabetes is an autoimmune disease. An autoimmune disease results when the body's system for fighting infection (the immune system) turns against a part of the body. In diabetes, the immune system attacks the insulin-producing beta cells in the pancreas and destroys them. The pancreas then produces little or no insulin. A person who has type 1 diabetes must take insulin daily to live.
Type 2 Diabetes
With type 2 diabetes, the body does not respond properly to insulin. Youngsters who are inactive, overeat, and have a family history of diabetes have the greatest risk of developing type 2 diabetes. Children in minority groups also have a higher incidence of type 2 diabetes.
Diabetes can occur any time, even in the first year of life. The diagnosis often is delayed in infants and toddlers until the child is very sick, because the symptoms at this age are not very specific. The following link will take you to the American Diabetes Association.