Diabetes is a lifelong condition that causes a person's blood sugar level to become too high.
The hormone insulin – produced by the pancreas – is responsible for controlling the amount of glucose in the blood
There are two main types of diabetes:
- type 1 – where the pancreas doesn't produce any insulin
- type 2 – where the pancreas doesn't produce enough insulin or the body's cells don't react to insulin
These pages are about type 2 diabetes. Read more about type 1 diabetes.
Another type of diabetes, known as gestational diabetes, occurs in some pregnant women and tends to disappear after birth.
Symptoms of diabetes
The symptoms of diabetes occur because the lack of insulin means glucose stays in the blood and isn't used as fuel for energy.
Your body tries to reduce blood glucose levels by getting rid of the excess glucose in your urine.
Typical symptoms include:
- feeling very thirsty
- passing urine more often than usual, particularly at night
- feeling very tired
- weight loss and loss of muscle bulk
Read more about the symptoms of type 2 diabetes.
See your GP if you think you may have diabetes. It's very important for it to be diagnosed as soon as possible as it will get progressively worse if left untreated.
Read about how type 2 diabetes is diagnosed.
Causes of type 2 diabetes
Type 2 diabetes occurs when the body doesn't produce enough insulin to function properly, or the body's cells don't react to insulin. This means glucose stays in the blood and isn't used as fuel for energy.
Type 2 diabetes is often associated with obesity and tends to be diagnosed in older people. It's far more common than type 1 diabetes.
Read about the causes and risk factors for type 2 diabetes.
Treating type 2 diabetes
As type 2 diabetes usually gets worse, you may eventually need medication – usually tablets – to keep your blood glucose at normal levels.
Read more about the treatment of type 2 diabetes.
Complications of type 2 diabetes
Diabetes can cause serious long-term health problems. It's the most common cause of vision loss and blindness in people of working age.
Everyone with diabetes aged 12 or over should be invited to have their eyes screened once a year for diabetic retinopathy.
Diabetes is also responsible for most cases of kidney failure and lower limb amputation, other than accidents.
People with diabetes are up to five times more likely to have cardiovascular disease, such as a stroke, than those without diabetes.
Read more about the complications of type 2 diabetes.
Preventing type 2 diabetes
If you're at risk of type 2 diabetes, you may be able to prevent it developing by making lifestyle changes.
Living with type 2 diabetes
If you already have type 2 diabetes, it may be possible to control your symptoms by making the above changes. This also minimises your risk of developing complications.
Read more about living with type 2 diabetes.