Type 1 Diabetes

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This topic provides general information about type 1 diabetes for people who do not have the disease. If you are looking for information on management of type 1 diabetes, one of the following topics may meet your needs:

• Type 1 Diabetes: Recently diagnosed, if you have been told recently that you or your child has type 1 diabetes.
• Type 1 Diabetes: Living With the Disease, if you or your adolescent has type 1 diabetes. If you have not read the topic Type 1 Diabetes: Recently Diagnosed, you may want to read it first.
• Type 1 Diabetes: Children Living With the Disease, if your child age 11 or younger has type 1 diabetes. If you have not read the topic Type 1 Diabetes: Recently Diagnosed, you may want to read it first.
• Type 1 Diabetes: Living With Complications, if you have complications, such as eye, kidney, heart, nerve, or blood vessel disease, caused by diabetes.

If you are looking for information about type 2 diabetes, see the topic Type 2 Diabetes.

What is type 1 diabetes?

Type 1 diabetes is a lifelong disease that develops when the pancreas stops producing insulin. Insulin lets blood sugar—also called glucose—enter your body's cells, where it is used for energy. Without insulin, the amount of sugar in the blood rises above a normal level, and the cells do not get the sugar they need. Over time, high blood sugar can damage blood vessels and nerves throughout your body and increase your risk of eye, heart, blood vessel, nerve, and kidney diseases. If your blood sugar level becomes very high, a life-threatening chemical imbalance (diabetic ketoacidosis) can develop.

Type 1 diabetes can develop at any age, but it usually develops in children and young adults, which is why it used to be called juvenile diabetes. It has also been called insulin-dependent diabetes mellitus (IDDM) because insulin injections must be taken daily.

About 5% to 10% of all people with diabetes have type 1.¹Type 2 diabetes is the most common type of diabetes. Other forms of the disease include gestational and secondary diabetes.

What causes type 1 diabetes?

Insulin normally is made by beta cells in a portion of the pancreas called the islet tissue. For unknown reasons, type 1 diabetes develops because the body destroys the beta cells. This is called an autoimmune disease.

Some people inherit a tendency for type 1 diabetes. People who have a parent, brother, or sister with type 1 diabetes are more likely than other people to develop the disease. But most people with type 1 diabetes do not have a family history of it. Even with a family history of diabetes, you might not develop the disease unless you are exposed to something in the environment that triggers it. Experts debate whether enteroviral infections, especially Coxsackie B, and not being breast-fed beyond 3 months of age may raise the risk for type 1 diabetes.

Other factors that increase your risk are being white and having islet cell antibodies in your blood.

What are the symptoms?

Symptoms of diabetes are increased thirst, increased urination, weight loss, and sometimes increased appetite. These symptoms usually appear over a few days to weeks. Occasionally, some people notice symptoms after an illness, such as the flu. They may think the diabetes symptoms are related to the flu and not seek medical care early.

Sometimes, a person may develop symptoms of diabetic ketoacidosis before seeking medical care. Symptoms include:

• Flushed, hot, dry skin.
• Loss of appetite, abdominal pain, and vomiting.
• A strong, fruity breath odor (similar to nail polish remover or acetone).
• Fast and shallow breathing.
• Restlessness, drowsiness, difficulty waking up, confusion, or coma.

How is type 1 diabetes diagnosed?

A health professional diagnoses diabetes using a medical history, physical examination, and blood tests to measure glucose. Some people are diagnosed with type 1 diabetes because they have diabetic ketoacidosis.

How is it treated?

Treatment for type 1 diabetes focuses on keeping blood sugar levels within a target range. Treatment requires:

• Taking daily insulin injections or using an insulin inhaler.
• Eating a healthy diet that spreads carbohydrate throughout the day.
• Monitoring blood sugar levels at home.
• Getting regular exercise.

Treatment may be adjusted based on the results of daily home blood sugar tests and other tests and examinations.

In some situations, a person may have a pancreas transplant, which allows his or her body to produce insulin. A pancreas transplant may be done at the same time a person has a kidney transplant. Surgery to insert pancreas cells (islet cell transplant) is an experimental treatment that is being done in some research centers. Both surgeries are expensive. Afterward, the person must take immunosuppressant medication to prevent rejection of the new tissue.

People with type 1 diabetes can live long, healthy lives if they keep their blood sugar levels as close to normal as possible. When a small child has diabetes, the parents have the responsibility for blood sugar control. As the child grows, he or she can take more responsibility for diabetes care.

Can I prevent type 1 diabetes?

Currently there is no way to prevent type 1 diabetes. However, studies are being done to look at ways of preventing or delaying the onset of diabetes in people who are most likely to develop the disease.

Tight control of blood sugar and blood pressure can help people with type 1 diabetes prevent or delay the development of complications, such as damage to the eyes, kidneys, heart, blood vessels, and nerves.

Frequently Asked Questions

Type 1 diabetes develops because the body's immune system destroys the beta cells which are in the islet tissue in the pancreas . These beta cells produce insulin. So people with type 1 diabetes cannot make their own insulin.

You can inherit a tendency to develop type 1 diabetes, but most people who have the disease have no family history of it. Diabetes experts believe that a genetic tendency and some environmental factors may increase the risk of developing type 1 diabetes. Possible environmental factors include enteroviral infections—especially Coxsackie B infections.

Despite concerns about vaccines (particularly those against whooping cough and Haemophilus influenza B, or Hib), studies have not found a relationship between being vaccinated and developing type 1 diabetes.²

Symptoms of type 1 diabetes usually develop quickly, over a few days to weeks, and are caused by blood sugar levels rising above the normal range (hyperglycemia). Early symptoms may be overlooked, especially if the person has recently had an illness, such as influenza (flu). Early symptoms include:

• Frequent urination, which may be more noticeable at night. Some young children who have learned to use the toilet may start wetting the bed during naps or at night.
• Extreme thirst and a dry mouth.
• Weight loss.
• Increased hunger (possibly).

Sometimes the blood sugar level rises excessively before a person knows something is wrong. Because insulin is not available, the cells in the body are unable to get the sugar (glucose) they need for energy. The body begins to break down fat and muscle for energy. When fat is used for energy, ketones—or fatty acids—are produced and enter the bloodstream, causing the chemical imbalance diabetic ketoacidosis. This is a life-threatening condition. Symptoms of diabetic ketoacidosis are:

• Flushed, hot, dry skin.
• Loss of appetite, abdominal pain, and vomiting.
• A strong, fruity breath odor (similar to nail polish remover or acetone).
• Rapid, deep breathing.
• Restlessness, drowsiness, difficulty waking up, confusion, or coma. Young children may lack interest in their normal activities.

Type 1 diabetes develops because the body destroys the beta cells in the islet tissue of the pancreas that produce insulin. The rate at which the beta cells are destroyed varies. Infants and children usually develop the disease suddenly because the beta cells are destroyed rapidly. Adults tend to develop the disease slowly because the beta cells are destroyed gradually.

Occasionally, people notice diabetes symptoms after an illness, such as the flu. If they do not seek medical care quickly, the lack of insulin can cause the blood sugar level to rise much higher than normal. The body then uses fat and muscle for energy, which causes the release of ketones, or fatty acids. Ketones can lead to a chemical imbalance called diabetic ketoacidosis. It is a medical emergency. Symptoms of diabetic ketoacidosis include confusion; strong, fruity breath; and drowsiness, or even coma.

Sometimes after receiving initial treatment for type 1 diabetes, people have a period of time—from a few weeks to a few months—when the pancreas is again able to produce insulin. This is often called the honeymoon period. At this time, a person may need to take little or no insulin, depending on how much insulin the pancreas produces. When the honeymoon period is over, the person needs to take insulin for the rest of his or her life.

Every person who has type 1 diabetes requires treatment designed for his or her needs. Treatment involves:

• Taking insulin.
• Eating a healthful diet that spreads carbohydrate throughout the day.
• Getting regular exercise.
• Monitoring blood sugar levels (using a home blood sugar meter).

People with type 1 diabetes often have blood sugar levels outside of their target range. These out-of-range levels happen because injections of insulin cannot control blood sugar as smoothly as natural insulin made by your body. Blood sugar below a normal range (hypoglycemia) can develop quickly and lead to an emergency in only a few minutes. On the other hand, high blood sugar levels (hyperglycemia) usually develop slowly over hours or days. If blood sugar levels continue to rise, diabetic ketoacidosis can develop.

Over time, diabetes can damage the body's tissues. Persistent high blood sugar can damage the eyes (diabetic retinopathy), kidneys (diabetic nephropathy), nerves (diabetic neuropathy), and heart (leading to heart attacks). It also can damage blood vessels, leading to strokes and blockage of other arteries, especially in the legs. People who keep their blood sugar levels as close to normal as possible often can prevent—or at least delay—these complications. However, some people still develop complications even with good blood sugar control.

People who work closely with their health professionals and follow their prescribed treatment usually feel better and more in control of their lives.

Planning pregnancy when you have type 1 diabetes

Women who want to plan a pregnancy need to talk to their health professional about making sure they have good control of their blood sugar. Higher-than-normal blood sugar levels during the first trimester of pregnancy raise the risk of birth defects. Good preconception care of diabetes appears to reduce the risk of birth defects. Women should try to have a glycohemoglobin (A1c) level that is less than 1% above the normal range.³

Women with diabetes who do not want to be become pregnant should make sure to use birth control. This reduces the risk of birth defects in unplanned pregnancies.

Risk factors for type 1 diabetes include:

• Family history of type 1 diabetes. Having a family history of the disease increases the chance that a person will have islet cell antibodies, but it does not predict that a person will have the disease. Only about 10% to 15% of people with type 1 diabetes have a family history of the disease.²
  • If the father has the disease, a child has a 6% risk of developing it.
  • If a sibling has the disease, a child has a 5% risk of developing it.
  • If the mother has the disease, a child has a 2% risk of developing it.
  • If an identical twin has the disease, the other twin has a 30% to 50% risk of developing it.
  • If a parent and one sibling have the disease, a child has a 30% risk of developing it.
• Race. White people have a greater risk for developing type 1 diabetes than black, Asian, or Hispanic people.
• Presence of islet cell antibodies in the blood. People who have both a family history of type 1 diabetes and islet cell antibodies in their blood are likely to develop the disease at some time.
• Certain viral infections during childhood. A child who has enterovirus infections, particularly Coxsackie B infections, has a risk almost 6 times greater than other children for developing type 1 diabetes. However, this does not mean that the child will definitely develop the disease. In fact, doctors are uncertain if these infections play a role in the development of diabetes.⁴

Call 911 or other emergency services immediately if:

• A person is losing consciousness or becomes unconscious. He or she may have low blood sugar, called hypoglycemia.
• A person is drowsy, confused, breathing fast, and their breath smells fruity or like nail polish. He or she may have the life-threatening chemical imbalance diabetic ketoacidosis.

Call a health professional if:

• You (or your child) have increased urination, increased thirst, weight loss, and possibly increased appetite. These symptoms may indicate type 1 diabetes.
• You have a family history of type 1 diabetes and want to be tested.

Watchful Waiting

Watchful waiting is a period of time during which you and your health professional observe your symptoms or condition without using medical treatment. Watchful waiting is not appropriate if you think you or your child may have symptoms of type 1 diabetes, such as increased urination, increased thirst, weight loss, and possibly increased appetite. A blood test is all that is needed to determine whether a person has the disease.

Who To See

The following health professionals can diagnose and treat diabetes:

• Endocrinologist
• Family medicine physician
• General practitioner
• Internist
• Pediatrician
• Nurse practitioner
• Physician assistant

To prepare for your appointment, see the topic Making the Most of Your Appointment

Many people are not diagnosed with type 1 diabetes until they are admitted to a hospital for diabetic ketoacidosis (DKA). This life-threatening condition occurs when ketones, or fatty acids, are produced as the body burns fat and muscle instead of glucose for fuel. DKA develops in people with type 1 diabetes (and some people with type 2 diabetes) when their blood sugar is very high.

During hospitalization, people with DKA will be watched closely and receive tests to measure the levels of electrolytes and sugar (glucose) in their blood.

If a person is not in ketoacidosis, a health professional uses blood sugar tests, the American Diabetes Association's criteria for symptoms, a medical history, and a physical examination to diagnose type 1 diabetes.

A blood glucose test is used to measure blood sugar. This test is done preferably after fasting, but it can be done at any time, even if you have recently eaten.

Other tests that may suggest diabetes

A hemoglobin A1c test is recommended for monitoring blood sugar control after treatment has begun because it estimates average blood sugar level over the previous 2 to 3 months. It may be done when a person is diagnosed, and it may be used as a comparison for blood sugar control after treatment starts.

Neither a home blood sugar test nor a urine test for sugar is recommended to screen for or diagnose diabetes.

Early Detection

Screening for type 1 diabetes is not recommended by the American Diabetes Association. Such screening would include testing everyone for islet cell antibodies. This test can show if a person is more likely to get type 1 diabetes.

People who are found to have islet cell antibodies may be able to participate in studies about preventing type 1 diabetes. These people need to be referred to a medical center conducting a type 1 diabetes prevention study.⁵

Treatment for adults

Type 1 diabetes requires lifelong treatment to keep blood sugar levels within a target range. Treatment includes:

• Taking several insulin injections every day, using an insulin pump, or using inhaled insulin.
• Monitoring blood sugar levels several times a day using a home blood sugar meter.
• Eating a healthful diet that spreads carbohydrate throughout the day, to prevent high blood sugar levels after meals.
• Regular physical exercise, because exercise helps the body to use insulin more efficiently. Exercise may also lower your risk for heart and blood vessel disease.
• Regular medical checkups to monitor and adjust treatment as needed. Screening tests and exams need to be done regularly to watch for signs of complications, such as eye, kidney, heart, blood vessel, and nerve diseases.
• Not smoking.
• Not drinking alcohol if the person is at risk for periods of low blood sugar.

A regular daily schedule makes managing blood sugar levels easier. Blood sugars are easier to predict and control when mealtimes, amounts of food, and exercise are similar every day.

Many people find out that they have type 1 diabetes when they are admitted to a hospital for diabetic ketoacidosis. If their symptoms are severe, they may need to be treated in an intensive care unit. Treatment for diabetic ketoacidosis includes fluids given through a vein (intravenous, or IV) to treat dehydration and to balance electrolytes, and insulin to lower the blood sugar level and stop the body from producing ketones.⁶

Treatment for children

Treatment for children includes all of the above measures to keep blood sugar levels within the child's target range. Treatment for children should also allow for normal growth and development. See the topics Type 1 Diabetes: Recently Diagnosed and Type 1 Diabetes: Children Living With the Disease.

When a small child has diabetes, the parents have the responsibility for blood sugar control. As the child grows, he or she can take more responsibility for diabetes care.

Preventing type 1 diabetes

Currently there is no way to prevent type 1 diabetes, but ongoing studies are exploring ways to prevent diabetes in those who are most likely to develop it. People who have a parent, brother, or sister with type 1 diabetes and are willing to participate in one of these studies should talk with their health professional. They may want to be tested for islet cell antibodies, because if they have these antibodies, they are more likely to get diabetes.

Vaccines have not been found to contribute to the development of type 1 diabetes.⁷ Children who are at risk for developing diabetes still need to get the recommended immunizations. See the childhood immunizations schedule recommended by the U.S. Advisory Committee on Immunization Practices, the American Academy of Pediatrics, and the American Academy of Family Physicians.

Preventing diabetes complications

People with type 1 diabetes can help prevent or delay the development of complications such as eye, kidney, heart, blood vessel, and nerve diseases by keeping their blood sugar near normal levels. They also need regular medical checkups to detect early signs of complications. If complications are treated early, the damage may be stopped, slowed, or possibly reversed.

People who have other health problems along with diabetes, such as high blood pressure or high cholesterol, need to treat those conditions. Also, not smoking can reduce the risk of complications. Having other health problems can increase the risk for complications from diabetes.

Preventing flu and pneumococcal disease

People who have diabetes should have a flu shot every year and a pneumococcal vaccine. Usually, people need only one dose of the pneumococcal vaccine. But doctors sometimes recommend a second dose for some people, especially if they have a long-term disease. Talk with your doctor about whether you need a second dose. The pneumococcal vaccine helps prevent infections caused by pneumococcal bacteria. People with diabetes, especially those who have heart or kidney disease, are at high risk for complications, hospitalization, and death from flu and pneumococcal disease.⁸

People who have type 1 diabetes need to work closely with their health professionals to find the right balance of diet, insulin, and exercise to keep their blood sugar levels within a target range. That combination will vary over time, especially for children.

Daily treatment for diabetes includes:

• Taking multiple insulin injections or using an insulin pump.
• Eating a healthful diet that spreads carbohydrate throughout the day.
• Getting physical activity.
• Checking blood sugar levels several times a day and, when necessary, during the night.

Other steps to take

People with type 1 diabetes also need to:

• Wear medical identification at all times so that, in case of emergency, health professionals can see that they have diabetes.
• Treat high and low blood sugar levels quickly to prevent an emergency.
• Take extra care of their feet, gums, and teeth to prevent problems that may develop because of high blood sugar.
• Know how to adjust their diet or insulin doses when they are sick or become pregnant.
• Have regular medical checkups to monitor the disease and adjust treatment as needed.

People with type 1 diabetes must take insulin every day because their pancreas does not produce it. Insulin helps blood sugar (glucose) enter the body's cells to be used for energy. Insulin can be given as an injection into the fatty tissue under the skin or through an insulin pump.

Usually people with type 1 diabetes take a combination of types of insulin, such as a long-acting insulin once or twice a day and a rapid-acting insulin before each meal. The amount and type of insulin needed varies for each person. Also, the amount and type of insulin needed changes over time, depending on age, hormones (such as during rapid growth or pregnancy), and changes in exercise routine. In addition, a person may need higher doses of insulin during times of illness or emotional stress.

Other medications may be needed if a person develops complications from diabetes, such as kidney disease.

A person also may need medications to treat high blood pressure or high cholesterol and help prevent complications from diabetes. If you are 40 or older, talk to your health professional about taking a low-dose aspirin daily to help prevent heart attack, stroke, or other large blood vessel disease.

Surgery for type 1 diabetes is done only in special situations.

• Surgery to replace the pancreas (pancreas transplant) may be done when a person is receiving another organ, such as a kidney.
• Surgery to insert working pancreas cells (islet cell transplant) is experimental.

These surgeries are very expensive. After having one of these surgeries, a person must take medication for the rest of his or her life to prevent the body from rejecting the new tissue (immunosuppression medications).

People who have type 1 diabetes need to avoid products that promise a “cure.” None exists. They also need to avoid products for diabetes that are advertised by testimonials without a sound medical basis. These products or remedies may be harmful and costly. They also might cause people to delay or avoid getting other forms of treatment that have been proved to work.

Online Resource

Organizations

• Diabetic Nephropathy
• Diabetic Neuropathy
• Diabetic Retinopathy
• Type 1 Diabetes: Children Living With the Disease
• Type 1 Diabetes: Living With Complications
• Type 1 Diabetes: Living With the Disease
• Type 1 Diabetes: Recently Diagnosed
• Type 2 Diabetes
• Type 2 Diabetes in Children
• Type 2 Diabetes: Living With Complications
• Type 2 Diabetes: Living With the Disease
• Type 2 Diabetes: Recently Diagnosed

Citations

1. U.S. Centers for Disease Control and Prevention (2005). National Diabetes Fact Sheet. Atlanta: U.S. Department of Health and Human Services. Available online: http://www.diabetes.org/uedocuments/NationalDiabetesFactSheetRev.pdf.

2. Lawson ML, Muirhead SE (2001). What is type 1 diabetes? In HC Gerstein, RB Haynes, eds., Evidence-Based Diabetes Care, pp. 124–150. Hamilton, ON: BC Decker.

3. American Diabetes Association (2004). Preconception care of women with diabetes. Clinical Practice Recommendations 2004. Diabetes Care, 27(Suppl 1): S76–S78.

4. Atkinson MA, Eisenbarth GS (2001). Type 1 diabetes: New perspectives on disease pathogenesis and treatment. Lancet, 358(9277): 221–229.

5. American Diabetes Association (2004). Prevention of type 1 diabetes mellitus. Clinical Practice Recommendations 2004. Diabetes Care, 27(Suppl 1): S133.

6. American Diabetes Association (2004). Hyperglycemic crises in diabetes. Clinical Practice Recommendations 2004. Diabetes Care, 27(Suppl 1): S94–S102.

7. Diabetes Workshop Panel, Institute for Vaccine Safety (1999). Childhood immunizations and type 1 diabetes: Summary of an Institute for Vaccine Safety workshop. Pediatric Infectious Disease Journal, 18(3): 217–222.

8. American Diabetes Association (2004). Influenza and pneumococcal immunization in diabetes. Clinical Practice Recommendations 2004. Diabetes Care, 27(Suppl 1): S111–S113.

Other Works Consulted

• American Diabetes Association (2006). Pancreas and islet transplantation in type 1 diabetes. Position statement. Diabetes Care, 29(4): 935.

• Pickup J, Keen H (2002). Continuous subcutaneous insulin infusion at 25 years. Diabetes Care, 25(30): 593–598.

• White SA, et al. (2001). Human islet cell transplantation: Future prospects. Diabetic Medicine, 18(2): 78–103.

Author:	Robin Parks, MS	Last Updated November 21, 2006
Medical Review:	Caroline S. Rhoads, MD - Internal Medicine Matthew I. Kim, MD - Endocrinology & Metabolism
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