Diabetes is a long-term (chronic) condition caused by too much glucose (sugar) in the blood. It is also known as diabetes mellitus.

In the UK, diabetes affects approximately 2.3 million people, and it's thought there are at least half a million more people who have the condition but are not aware of it.

How does diabetes occur?

Normally, the amount of sugar in the blood is controlled by a hormone called insulin, which is produced by the pancreas (a gland behind the stomach). When food is digested and enters your bloodstream, insulin moves any glucose out of the blood and into cells, where it is broken down to produce energy.

However, in those with diabetes, the body is unable to break down glucose into energy. This is because there is either not enough insulin to move the glucose, or because the insulin that is there does not work properly.

There are two types of diabetes - type 1 and type 2. This article focuses on type 1 diabetes (go to 'useful links' for information about type 2 diabetes).

What is type 1 diabetes?

Type 1 diabetes occurs when the body produces no insulin. It is often referred to as insulin-dependent diabetes. It is also sometimes known as juvenile diabetes, or early-onset diabetes, because it usually develops before the age of 40, often in the teenage years.

Type 1 diabetes is far less common than type 2 diabetes, which occurs when there is too little insulin produced by the body to work, or when the cells in the body do not react properly to insulin. People with type 1 diabetes make up only 5-15% of all people with diabetes.

If you have type 1 diabetes, you will need to take insulin injections for life. You must also make sure that your blood glucose levels stay balanced by eating a healthy diet and carrying out regular blood tests.