3D medical animation still of type 1 diabetes showing insulin production in a diabetic patient and in normal condition.
**Type 1 diabetes**, also called **diabetes mellitus type 1**, is an autoimmune disease that results in high blood sugar. This is because the body cannot create enough of the hormone insulin. People with type 1 diabetes need to take insulin injections to stay healthy. If they do not get enough insulin, they can become very sick or even die. People with type 1 diabetes have an increased risk of developing diseases involving blood vessels such as stroke, heart disease or gangrene. About 15% of people with diabetes have type 1.

Cause
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Type 1 diabetes is a condition caused by a lack of insulin in the body. Insulin is a hormone produced by cells in the pancreas. Insulin is responsible for moving sugars out of the blood and into cells to be used by the body for energy. If insulin is not made, the body will search for other ways to get the sugars needed to feed the body's cells, including breaking down muscle and fat, leading to a loss of weight.

Insulin is not being produced in the pancreas due to an autoimmune condition attacking its cells. The body's immune system mistakenly attacks the cells responsible for producing insulin in the pancreas, the beta cell. The beta cells are damaged in a way that prevents them from producing more insulin. As more and more of these cells are damaged, less insulin is produced in the body. This means that more sugar remains in the bloodstream rather than being moved into cells. This high blood sugar causes the symptoms seen in type 1 diabetes.

The disease is thought to be strongly linked to genetic factors, but the trigger that starts the autoimmune disease is not currently known.

Epidemiology
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In the past, type 1 diabetes was generally thought to be a disorder in children and teenagers. However, it's now been found that adults can be diagnosed with the disease.

Although type 1 diabetes can now be diagnosed at any age, it is one of the most common chronic conditions in children and young adults. Being diagnosed at ages 5–7 or at the start of puberty is particularly common. Type 1 diabetes is also slightly more common in boys.

Cases of type 1 diabetes have been increasing across the world for several decades. Approximately 1 in 300 people are diagnosed with type 1 diabetes by the age of 18 in the United States.

Symptoms
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In type 1 diabetes, symptoms generally develop over a few days or weeks, though may take longer in adults. The main symptoms are:

* Feeling very thirsty
* Urinating more often than normal
* Exhaustion
* Loss of weight
* Bedwetting (especially in children)
* Blurring of sight
* Slow healing of wounds and grazes

Nausea, vomiting and heavy breathing are more serious symptoms that occur at a later stage in the disease.

Complications
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People with type 1 diabetes may have to deal with both short-term and long-term complications, particularly if the disease is not well managed.

### Short-term complications

#### Hypoglycaemia

Hypoglycaemia is when blood sugar levels decrease to below normal. This is most commonly due to overuse of medications for diabetes type 1 like insulin, poor diet control, and rigorous exercise. The risk of suffering from low blood sugar is increased by drinking alcohol. This may lead to various other symptoms, including confusion, loss of consciousness, clumsiness, seizures or death.

#### Diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is a very serious complication of type 1 diabetes. It is a medical emergency and requires rapid medical attention to prevent further damage to a patient, if left untreated it can potentially lead to death. DKA occurs when there is not enough insulin in the body to supply sugars to the body's cells. In order to give its cells enough energy to survive, the body begins to produce acidic ketone bodies which are then used to feed energy to the cells.

If too many ketone bodies build up the blood becomes acidic, damaging the body and leading to the symptoms:

* Vomiting
* Dehydration
* Difficult breathing
* Fast heartbeat
* Confusion
* Coma

### Long-term complications

If diabetes is not treated, even mildly raised blood sugar levels can damage nerves, organs and blood vessels in the body.

#### Small blood vessel complications

* Diabetic retinopathy, damage to the blood vessels prevent enough blood from reaching the eye. This can lead the eye's retina being damaged, resulting in loss of vision or blindness.
* Diabetic neuropathy, damage to blood vessels near nerves can result in reduced blood flow. This can damage the nerves, leading to a loss in the sense of touch, normally starting from the hands or feet, before spreading up the body.
* Diabetic nephropathy, blood vessels in the kidney become damaged, making the kidney work less effectively. In severe cases. this can result in kidney failure.
* Sexual dysfunction

#### Large blood vessel complications

* Increased risk of heart disease and stroke
* Narrowing of blood vessels (peripheral arterial disease).
* Diabetic foot, narrowing of blood vessels reduces sensitivity and slows wound healing in the foot. If not managed appropriately, can lead to ulceration and gangrene in the foot. In very severe cases, amputation may be required.

Management
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There is no known cure for diabetes. Instead, treatment is designed to help keep blood sugar levels normal in order to reduce the chances of complications developing as the disease progresses. There are two main method that are combined to manage diabetes type 1:

### Lifestyle

* Healthy eating: eating a diet focused on fruit and vegetables, whilst limiting fats salt and sugar helps keep blood sugar levels in check.
* Exercise: regular physical activity helps to lower your blood sugar level. A good goal to aim for is 150 minutes of exercise a week.
* Stopping smoking: smoking further increases the risk of heart disease, peripheral arterial disease and stroke. Stopping or reducing smoking will reduce the risk of these complications.
* Reducing alcohol: alcohol can either raise or lower blood sugar, and makes it difficult to monitor your own blood sugar levels. Drinking less alcohol can reduce these risks.

### Insulin injections

Type 1 diabetes occurs due to the bodies inability to produce its own insulin. To counter this, insulin can be injected into the blood manually. When diabetes is first diagnosed, a plan should be made for insulin treatment in order to not under or overdose, which can lead to serious complications. A diabetic should monitor their own blood sugar levels continuously to know whether they need a dose of insulin to lower their blood sugar.

There are different kinds of insulin that can be taken:

* Rapid-acting insulin and short-acting insulin get insulin into the bloodstream very quickly. They are typically taken before a meal to prepare for the rise in blood sugar that follows eating food.
* Long acting insulin provides insulin in the system for up to 24 hours. It is generally taken once a day