What is Diabetes, type 1?

Diabetes, type 1

What is type 1 diabetes?

If you have type 1 diabetes, you have too much glucose in your blood. Glucose is a kind of sugar your body uses for energy. But if it builds up in your blood, it can make you sick.

Diabetes doesn't go away. And if you don't treat it, you can get serious health problems. But if you take insulin and watch your condition closely, you can keep your blood sugar under control. You should be able to live a long and healthy life.

Key points for people with diabetes

Diabetes is a serious condition. But with the right treatment, you should be able to stay healthy.
If you have diabetes, you have too much glucose in your blood.
There are two main types of diabetes: type 1 and type 2. This information is for people with type 1 diabetes. For information about the other type, see Type 2 diabetes.
If you have type 1 diabetes, you need to control the glucose in your body with shots of a hormone called insulin. You'll also need to eat a healthy diet.

Over time, too much glucose in your blood can damage your blood vessels. This can lead to problems in your heart, eyes,

kidney
Your kidneys are organs that filter your blood to make urine. You have two of them, on either side of your abdominal cavity, toward your back.

kidneys and other parts of your body.
If you keep your blood glucose level as close to normal as possible, you might be able to avoid these problems.

What's a normal glucose level?

You always need to have some glucose in your blood. It comes from food and it gives your body energy. Every cell in your body needs glucose to work properly.

Diabetes is a long-term condition, but with the right treatment you can live a long and healthy life.

Normally, the amount of glucose in your blood is carefully controlled by a chemical called insulin. Insulin is a

hormones
Hormones are chemicals that are made in certain parts of the body. They travel through the bloodstream and have an effect on other parts of the body. For example, the female sex hormone estrogen is made in a woman's ovaries. Estrogen has many different effects on a woman's body. It makes the breasts grow at puberty and helps control periods. It is also needed to get pregnant.

hormone made by your pancreas, a

gland
A gland is any group of cells in the body that makes and releases something for use by another part of the body. For example, the thyroid gland makes a hormone called thyroxine. This acts on receptors within cells. By acting on the receptors it gives the cells a message to speed up their metabolism and work harder.

gland that sits behind your stomach. Insulin helps move glucose from your blood into your body's cells. Your cells use the glucose as energy. Insulin keeps your blood level of glucose steady.

Doctors measure how much glucose is in your blood in milligrams per deciliter. The short version is mg/dL.

People who don't have diabetes have between 70 mg/dL and about 120 mg/dL glucose in their blood.

Source:
National Diabetes Information Clearinghouse (NDIC).
What diabetes is.
National Institute of Diabetes and Digestive and Kidney Diseases. Available at http://diabetes.niddk.nih.gov/dm/pubs/type1and2 (accessed on 11 June 2008.)

¹ Your doctor might talk about your blood glucose level using just the number. For example, your doctor might say, "Your blood glucose is 120."

Normally, your blood glucose level goes up and down throughout the day. Before breakfast, a normal level is less than 100 mg/dL.

Types of diabetes

There are two main types of diabetes: type 1 and type 2.
Type 1 diabetes usually starts in adolescence.
Type 2 comes on gradually, usually you're 40 years or older.
There's also a condition called impaired glucose tolerance. This isn't diabetes, but it does increase your chances of getting diabetes.
Some women get a kind of diabetes that only happens while they're pregnant. This is called gestational diabetes.

This information is for people with type 1 diabetes. For more information about other types of diabetes, see:

Type 1 diabetes

Type 1 diabetes usually starts when you're in your teens or when

puberty
Puberty is the time when boys and girls develop secondary sexual characteristics. For boys, the major changes include pubic hair, a deeper voice, and growth of their penis and testicles. For girls, major changes include pubic hair, breasts and starting to have periods. After puberty, girls are able to become pregnant and boys are able to father children.

puberty begins. Between 5 percent and 10 percent of people with diabetes have type 1.

Source:
National Institute of Diabetes and Digestive and Kidney Diseases.
National diabetes statistics: 2007.
June 2008. Available at http://www.diabetes.niddk.nih.gov/dm/pubs/statistics (accessed on 19 December 2008 2008).

If you have type 1 diabetes, your body has stopped making

insulin
Insulin is a hormone that helps your body use glucose, a type of sugar that gives you energy. Insulin keeps your levels of glucose steady. It also helps glucose get into your cells from your blood. People who have diabetes do not have enough insulin or do not react to insulin strongly enough. This leads to too much glucose in their blood.

insulin. This kind of diabetes used to be called insulin-dependent diabetes mellitus (or IDDM for short) because it can be controlled by taking insulin. You might also hear people call it juvenile-onset diabetes. It was called this because it tends to start in childhood.

What happens in type 1 diabetes?

If you have diabetes, your body can't control how much glucose is in your blood. Instead of the glucose being gradually used up as fuel by your cells, it builds up in your blood. You'll hear the word hyperglycemia a lot. It means having too much glucose in your blood. To find out how this affects you, see What are the symptoms of type 1 diabetes?

You need insulin to keep your blood glucose level under control. But when you have type 1 diabetes, your body stops making insulin.

What causes it?

Usually, type 1 diabetes is an autoimmune disease. This means that the cells in your

immune system
The immune system is made up of the parts of the body that are devoted to fighting infection. The body is constantly being threatened by infections from things like bacteria, viruses and parasites. The immune system fights these infections in different ways. At the microscopic level, the immune system uses antibodies and white blood cells, which travel in the blood and target infectious agents, such as bacteria. These microscopic parts of the immune system either kill the infectious agent directly, or take it to other parts of the body, like the spleen, where it can be dealt with. The lymph nodes are another important part of the immune system. Within them, white blood cells filter through the foreign material that has entered the blood, to see if there are any infections. When you have a swollen gland during a cold, this is actually a lymph node that is reacting to the infection. Unfortunately, it is possible for the immune system to become confused and to use its destructive powers to target healthy parts of the body. Diseases that result from this type of situation are called autoimmune diseases.

immune system, which normally fight germs, attack some of your own cells by mistake. In type 1 diabetes, your immune system attacks the cells making insulin in your

pancreas
Your pancreas is an organ that's behind your stomach. It makes several different chemicals. Some of the chemicals help your body digest food. Your pancreas also makes a chemical called insulin, which helps your body use the sugar in your blood.

pancreas.

You can get type 1 diabetes at any age. But it usually takes years for the immune system to kill all the cells that make insulin.

Source:
Powers AC.
Diabetes mellitus.
In: Braunwald E, Fauci AS, Kasper DL, et al (editors). Harrison's Principles of Internal Medicine. McGraw-Hill, New York, U.S.A.; 2001.

³ Exactly how long it takes depends in part on your

genes
Your genes are the parts of your cells that contain instructions for how your body works. Genes are housed on chromosomes, structures that sit in the nucleus at the middle of each of your cells. You have 23 pairs of chromosomes in your normal cells, each of which has thousands of genes. You get one set of chromosomes, and all of the genes that are on them, from each of your parents.

genes.

Why me?

No one knows why the immune system starts killing the cells in the pancreas. The attack might be started by

viruses
Viruses are microbes (tiny organisms) that need the cells of humans or other animals to exist. They use the machinery of cells to reproduce. Then they spread to other cells in the body.

viruses, but no one knows for sure. Some of the things researchers think have a role are:

The virus that causes German measles (also called

rubella
Rubella is a childhood infection caused by a virus. It usually starts with mild cold symptoms, a sore throat and swollen glands. After that, you get a pink rash that spreads from your head to the rest of your body. Some people call it German Measles. The measles, mumps and rubella (MMR) vaccine protects children from getting rubella.

rubella)
The virus that causes

hand-foot-and-mouth disease
Hand-foot-and-mouth disease is a common problem, particularly in young children. It happens when they get infected with a certain type of virus. They get a fever and bumps or blisters on their tongue and mouth. They also get tender bumps on their hands, feet and buttocks. They may get these bumps in their genital area. Hand-foot-and-mouth disease usually comes on suddenly, and clears up in a few days.

hand-foot-and-mouth disease
Your genes. If your genes give you a low chance of getting diabetes, you might not be affected by these other things.

Source:
Watkins PJ.
ABC of Diabetes.
5th edition. BMJ Books, London, UK; 2002.

⁴

You probably won't notice when the cells that make insulin start dying. You need only a small number of these cells to keep your blood glucose level under control. But once you lose about four-fifths (or 80 percent) of these cells, you start to get symptoms of diabetes. This happens because glucose starts to build up in your blood.

Source:
Powers AC.
Diabetes mellitus.
In: Braunwald E, Fauci AS, Kasper DL, et al (editors). Harrison's Principles of Internal Medicine. McGraw-Hill, New York, U.S.A.; 2001.

Sources for the information on this page:

National Diabetes Information Clearinghouse (NDIC).What diabetes is. National Institute of Diabetes and Digestive and Kidney Diseases. Available at http://diabetes.niddk.nih.gov/dm/pubs/type1and2 (accessed on 11 June 2008.)

National Institute of Diabetes and Digestive and Kidney Diseases.National diabetes statistics: 2007.June 2008. Available at http://www.diabetes.niddk.nih.gov/dm/pubs/statistics (accessed on 19 December 2008 2008).

Powers AC.Diabetes mellitus.In: Braunwald E, Fauci AS, Kasper DL, et al (editors). Harrison's Principles of Internal Medicine. McGraw-Hill, New York, U.S.A.; 2001.

Watkins PJ.ABC of Diabetes.5th edition. BMJ Books, London, UK; 2002.

This information was last updated on Jan 07, 2009

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