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Causes

By Mayo Clinic staff

The exact cause of type 1 diabetes is unknown. Scientists do know that in most people with type 1 diabetes, the body's own immune system — which normally fights harmful bacteria and viruses — mistakenly destroys the insulin-producing (islet) cells in the pancreas. Genetics may play a role in this process, and exposure to certain viruses may trigger the disease.

Insulin key to sugar entering cells
Whatever the cause, once the islet cells are destroyed, your child will have little or no insulin. Normally, the hormone insulin helps glucose enter your child's cells to provide energy to the muscles and tissues. Insulin comes from the pancreas, a gland located just behind the stomach. When everything is working properly, once you eat, the pancreas secretes insulin into the bloodstream. As insulin circulates, it acts like a key by unlocking microscopic doors that allow sugar to enter the body's cells. Insulin lowers the amount of sugar in the bloodstream, and as the blood sugar level drops, so does the secretion of insulin from the pancreas.

The liver acts as a glucose storage and manufacturing center. When insulin levels are low — when you haven't eaten in a while, for example — the liver releases stored glycogen, which is then converted to glucose to keep your blood glucose level within a normal range.

Dangerous sugar level in bloodstream
In type 1 diabetes, none of this occurs because there's no insulin to let glucose into the cells. So instead of being transported into your child's cells, sugar builds up in your child's bloodstream, where it can cause life-threatening complications.

The cause of type 1 diabetes is different from the more familiar type 2 diabetes. In type 2, the islet cells are still functioning, but the body becomes resistant to insulin or the pancreas doesn't produce enough insulin.

Risk factors Symptoms
References
  1. The dangerous toll of diabetes. American Diabetes Association. http://www.diabetes.org/diabetes-statistics/dangerous-toll.jsp. Accessed Jan. 6, 2009.
  2. Levitsky LL, et al. Epidemiology, presentation, and diagnosis of type 1 diabetes mellitus in children and adolescents. http://www.uptodate.com/home.index.html. Accessed Jan. 5, 2009.
  3. Eisenbarth GS, et al. Pathogenesis of type 1 diabetes mellitus. http://www.uptodate.com/home.index.html. Accessed Jan. 5, 2009.
  4. McCulloch DK. Glycemic control and vascular complications in type 1 diabetes mellitus. http://www.uptodate.com/home.index.html. Accessed Jan. 5, 2009.
  5. Kidney disease (nephropathy). American Diabetes Association. http://www.diabetes.org/utils/printthispage.jsp?PageID=TYPE1DIABETES3_232930. Accessed Jan. 6, 2009.
  6. What is diabetes: Diabetes complications. Juvenile Diabetes Research Foundation. http://www.jdrf.org/index.cfm?page_id=101308. Accessed Jan. 6, 2009.
  7. Prevent diabetes problems: Keep your eyes healthy. National Institute of Diabetes and Digestive and Kidney Diseases. http://diabetes.niddk.nih.gov/dm/pubs/complications_eyes/index.htm. Accessed Jan. 6, 2009.
  8. McCulloch DK. Patient information: Preventing complications in diabetes mellitus. http://www.uptodate.com/home.index.html. Accessed Jan. 5, 2009.
  9. Skin complications. American Diabetes Association. http://www.diabetes.org/utils/printthispage.jsp?PageID=TYPE1DIABETES3_232934. Accessed Jan. 6, 2009.
  10. What people with diabetes need to know about osteoporosis. National Institute of Arthritis and Musculoskeletal and Skin Diseases. Accessed Jan. 9, 2009.
  11. Levitsky LL, et al. Management of type 1 diabetes mellitus in children and adolescents. http://www.uptodate.com/home.index.html. Accessed Jan. 5, 2009.
  12. Standards of medical care in diabetes -2009. Alexandria, Va.: American Diabetes Association. http://care.diabetesjournals.org/content/vol31/Supplement_1/. Accessed Jan. 28, 2009.
  13. Estimated average glucose, eAG. American Diabetes Association. http://professional.diabetes.org/GlucoseCalculator.aspx. Accessed Jan. 6, 2009.
  14. The basics of insulin. American Diabetes Association. http://www.diabetes.org/utils/printthispage.jsp?PageID=TYPE1DIABETES3_263601. Accessed Jan. 6, 2009.
  15. McCulloch DK. Patient information: Insulin therapy in type 1 diabetes mellitus. http://www.uptodate.com/home.index.html. Accessed Jan. 5, 2009.
  16. Levitsky LL, et al. Complications and screening in children and adolescents with type 1 diabetes mellitus. http://www.uptodate.com/home.index.html. Accessed Jan. 5, 2009.
  17. Robertson RP. Pancreas and islet transplantation in diabetes mellitus. http://www.uptodate.com/home.index.html. Accessed Jan. 6, 2009.
  18. Low blood sugar: Definition, symptoms. Juvenile Diabetes Research Foundation. http://www.jdrf.org/index.cfm?fuseaction=home.viewpage&page_id=EC9AC822-1321-C844-13C1013CF597E42F. Accessed Jan. 6, 2009.
  19. High blood sugar: Definition, symptoms. Juvenile Diabetes Research Foundation. http://www.jdrf.org/index.cfm?fuseaction=home.viewpage&page_id=EC92D98E-1321-C844-13EB771367A49526. Accessed Jan. 6, 2009.
  20. Ketoacidosis. American Diabetes Association. http://www.diabetes.org/type-1-diabetes/ketoacidosis.jsp. Accessed Jan. 6, 2009.
  21. Collazzo-Clavell M (expert opinion). Mayo Clinic, Rochester, Minn. Jan. 21, 2009.
  22. Diabetes and teens. Juvenile Diabetes Research Foundation. Accessed Jan. 20, 2009.
  23. Stalvey MS. Fifty years ago in the Journal of Pediatrics. Journal of Pediatrics. 2007: 150(1) http://www.mdconsult.com/das/article/body/115791309-2/jorg=journal&source=&sp=16726925&sid=788957128/N/562819/1.html?issn=0022-3476. Accessed Jan. 6, 2009.
  24. What is Type 1 Diabetes TrialNet? Type 1 Diabetes TrialNet. http://www.diabetestrialnet.org/about/index.htm. Accessed Jan. 6, 2009.
  25. International Expert Committee. International Expert Committee report on the role of the A1C assay in the diagnosis of diabetes. Diabetes Care. 2009;32:1.

DS00931

June 13, 2009

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