Diabetes is a lifelong condition that causes a person's blood sugar level to become too high.
The two main types of diabetes are:
The difference between the two types of diabetes is explained below.
In the UK, diabetes affects approximately 2.9 million people. There are also thought to be around 850,000 people with undiagnosed diabetes.
Symptoms of diabetes
The main symptoms of diabetes are:
- feeling very thirsty
- urinating frequently, particularly at night
- feeling very tired
- weight loss and loss of muscle bulk
Type 1 diabetes can develop quickly, over weeks or even days.
Many people have type 2 diabetes for years without realising because early symptoms tend to be general.
What causes diabetes?
The amount of sugar in the blood is usually 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 glucose out of the blood and into cells, where it is broken down to produce energy.
However, if you have diabetes, your body is unable to break down glucose into energy. This is because there is either not enough insulin to move the glucose, or the insulin produced does not work properly.
Type 1 diabetes
In type 1 diabetes, the body's immune system attacks and destroys the cells that produce insulin. As no insulin is produced, your glucose levels increase, which can seriously damage the body's organs.
Type 1 diabetes is often known 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 during teenage years.
Type 1 diabetes is less common than type 2 diabetes. About 10% of all people with diabetes have type 1 diabetes.
If you are diagnosed with type 1 diabetes, you will need insulin injections for the rest of your life. You will also need to pay special attention to certain aspects of your lifestyle and health to ensure your blood glucose levels stay balanced - for example, by eating a healthy diet and carrying out regular blood tests.
Read more about type 1 diabetes and living with diabetes.
Type 2 diabetes
Type 2 diabetes is where the body does not produce enough insulin, or the body's cells do not react to insulin. This is known as insulin resistance.
Type 2 diabetes is far more common than type 1 diabetes. In the UK, around 90% of all adults with diabetes have type 2 diabetes.
If you are diagnosed with type 2 diabetes, you may be able to control your symptoms simply by eating a healthy diet and monitoring your blood glucose level. However, as type 2 diabetes is a progressive condition, you may eventually need medication, usually in the form of tablets.
Type 2 diabetes is often associated with obesity. Obesity-related diabetes is sometimes referred to as maturity-onset diabetes because it is more common in older people.
Read more about type 2 diabetes, and use the BMI healthy weight calculator to check you are a healthy weight.
Gestational diabetes (in pregnancy)
During pregnancy, some women have such high levels of blood glucose their body is unable to produce enough insulin to absorb it all. This is known as gestational diabetes and affects around 5% of pregnant women.
Pregnancy can also make existing type 1 diabetes worse. Gestational diabetes can increase the risk of health problems developing in an unborn baby, so it is important to keep your blood glucose levels under control.
In most cases, gestational diabetes develops during the second trimester of pregnancy (weeks 14-26) and disappears after the baby is born. However, women who have gestational diabetes are at increased risk (30%) of developing type 2 diabetes later in life (compared to a 10% risk for the general population).
Read more about gestational diabetes.