Type 1 Diabetes
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Type 1 Diabetes

(Insulin Dependent Diabetes Mellitus; Juvenile-Onset Diabetes; Ketosis-Prone Diabetes; "Brittle" Diabetes; Diabetes Mellitus Type 1; Diabetes, Type 1)

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Type 1 diabetes is when the body does not make enough insulin. Insulin is a hormone that helps your body convert food into energy. Without insulin, glucose (sugar) from the food you eat cannot enter cells. So glucose builds up in the blood. Your body tissue becomes starved for energy.

Type 1 diabetes usually begins in children and young adults. Over the long-term, if type 1 diabetes is not adequately treated, high blood sugar levels can damage the blood vessels, heart, kidneys, eyes, nerves, and other tissues.


Most cases of type 1 diabetes are caused by the body's immune system attacking and destroying cells that make insulin. These cells are in the pancreas. The current theory is that some people have genes that make them prone to getting type 1 diabetes. For these people, certain things in the environment may trigger an immune system attack on the pancreas. The trigger or triggers have yet to be identified, but may be certain viruses, foods, chemicals, or drugs.

Some studies suggest that enterovirus infection—which is common and usually causes diarrhea and fever with or without rash—may contribute to the development of diabetes in some children. Children with relatively high birth weights are more likely to get diabetes than are those with lower weights.

The Pancreas

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Risk Factors

These factors increase your chance of developing type 1 diabetes. Tell your doctor if you have any of these risk factors:

  • Family history (parent, sibling) of type 1 diabetes
  • Age: starts at age 4 with peak at ages 11-13
  • Sex: more common in males than females
  • Race: more common in Caucasians, African Americans, and Hispanics than in Asians
  • Ethnicity: Northern European or Mediterranean
  • Bottle-feeding or short duration of breastfeeding
  • Birth weight above 10 pounds
  • Other autoimmune illness, including:


If you have any of these symptoms, do not assume it is due to type 1 diabetes. These symptoms may be caused by other conditions. Tell your doctor if you have any of these:

  • Weight loss
  • Increased urination
  • Extreme thirst
  • Hunger
  • Fatigue, weakness
  • Blurry vision
  • Irritability
  • Headaches

Destruction of insulin-producing pancreatic cells may occur so quickly that ketoacidosis (commonly known as diabetic coma) is the first sign of a problem. Symptoms of ketoacidosis include:

  • Vomiting and nausea
  • Abdominal pain
  • Dehydration (not enough fluid in the body)
  • Drowsiness
  • Abnormally deep and fast breathing
  • Coma
  • Dry skin and mouth
  • Fruity breath odor
  • Rapid pulse
  • Low blood pressure
  • Flushed face


The doctor will ask about your symptoms and medical and family history, and perform a physical exam.

Type 1 diabetes is diagnosed based on the results of blood tests and other criteria. These include:

  • Symptoms consistent with diabetes and a random blood test revealing a blood sugar level greater than or equal to 200 mg/dL* (11.1 mmol/L)
  • Blood sugar tests after you have not eaten for eight or more hours revealing blood sugar levels greater than or equal to 126 mg/dL (7.0 mmol/L) on two different days
  • Glucose tolerance test measuring blood sugar two hours after you consume glucose (rarely needed to diagnose type 1 diabetes)
*mg/dL = milligrams per deciliter of blood, mmol/L = millimole per liter of blood

Some children may be tested for insulin levels or anti-pancreas antibodies to confirm the diagnosis.


Diabetes treatment aims to maintain blood sugar at levels as close to normal as possible. Regular medical care is important for preventing or delaying complications.


Insulin injection replaces the natural insulin the pancreas would normally produce. The dosage is adjusted based on results of blood sugar tests before meals and at bedtime. You will need to have insulin shots two, three, or more times daily. Or you may wear an insulin pump that continually gives you a small amount of insulin. The pump connects to tubing and a small needle or catheter under the skin.


Amylin is made in the pancreas like insulin. In people with type 1 diabetes, this hormone is lacking, also like insulin. Researchers think that the post-meal glucose rise in people with type 2 diabetes is somehow related to the amylin deficiency. The drug pramlintide (Symlin) may be used when insulin therapy is insufficient to adequately control blood sugar.


If you have type 1 diabetes, you should meet regularly with a registered dietician. Generally speaking, it is best to:

  • Follow a well balanced meal plan incorporating a variety of food groups
  • Eat consistently at regular times each day, including a bedtime snack
  • Limit the amount of fat in the diet
  • Avoid highly refined carbohydrates (sugar or high fructose products)


Exercise is encouraged when blood sugar levels are consistently under control and there are no complications. Follow your doctor's advice on activity levels and restrictions. You may need to adjust your insulin regimen or diet to compensate for low glucose levels linked to exercise.

Blood Sugar Testing

Checking blood sugar levels during the day helps you track the amount of glucose in your blood. Testing is easy with a blood glucose monitor. You can also ask your doctor about continuous glucose monitoring systems that you wear all day.

Keep a record of the results to show your doctor. Your treatment plan may change based on your test results.

Pancreatic Transplant

This procedure is recommended if you have:

  • Severe kidney disease and have a kidney transplant at the same time as the pancreatic transplant
  • Acute diabetic complications or emergencies not preventable by insulin
  • Severe problems due to injecting large amounts of insulin
  • Severe and frequent diabetic complications


Currently, there is no known way to prevent type 1 diabetes. Researchers are studying immunosuppressive treatments that may benefit high-risk people.


American Diabetes Association

National Diabetes Information Clearinghouse


Canadian Diabetes Association

Team Diabetes Canada
Canadian Diabetes Association


American Association of Clinical Endocrinologists. American College of Endocrinology. Medical guidelines for the management of diabetes mellitus: the AACE system of intensive diabetes self-management. 2002 update. Endocrine Pract. 2002;8(suppl 1)S40-82.

The DCCT/Epidemiology of Diabetes Interventions and Complications Research Group. Retinopathy and nephropathy in patients with type 2 diabetes four years after a trial of intensive therapy. N Engl J Med. 2000;342:381-389.

Diabetes. National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/nccdphp/publications/aag/ddt.htm. Updated February 14, 2008. Accessed July 21, 2008.

Diabetes mellitus type 1. EBSCO Publishing DynaMed website. Available at: http://dynaweb.ebscohost.com/Detail.aspx?id=116244sid=0c9c3733-81cc-4c2a-9684-cfe4d807b81b@sessionmgr9. Accessed March 11, 2008.

Kearney PM, Blackwell L, Collins R, et al. Efficacy of cholesterol-lowering therapy in 18,686 people with diabetes in 14 randomised trials of statins: a meta-analysis. Lancet. 2008;371:117-125.

McMahon GT, Arky RA. Inhaled insulin for diabetes mellitus. N Engl J Med. 2007;356:497-502.

McQueen J. Pramlintide acetate. Am J Heal Pharm. 2005;62:2263-2272.

Nutrition principles and recommendations in diabetes. Diabetes Care. 2004;27(suppl 1)S36-46.

Pancreas transplantation in type 2 diabetes. Diabetes Care. 2004;27:S105.

Paviakis M, Khwaja K. Pancrease and islet cell transplantation in diabetes. Curr Opin Endocrinol Diabetes Obes. 2007;14:146-150.

Physical activity/exercise and diabetes. Diabetes Care. 2004;27(suppl 1)S58-62.

Scheid DC, McCarthy LH, Lawler FH, et al. Screening for microalbuminuria to prevent nephropathy in patients with diabetes: a systematic review of the evidence. J Fam Pract. 2001;50:661-668.

Type 1 diabetes. American Diabetes Association website. Available at: http://www.diabetes.org/type-1-diabetes.jsp. Accessed July 22, 2008.

*¹9/23/2008 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php: The Juvenile Diabetes Research Foundation Continuous Glucose Monitoring Study Group. Continuous glucose monitoring and intensive treatment of type 1 diabetes. N Engl J Med. 2008 Sep 8. [Epub ahead of print]

Last reviewed July 2008 by Richard Glickman-Simon, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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