Introduction 

Diabetes is a lifelong condition that causes a person's blood sugar level to become too high.

In England in 2010, there were approximately 3.1 million people aged 16 or over with diabetes (both diagnosed and undiagnosed).

By 2030, this figure is expected to rise to 4.6 million, with 90% of those affected having type 2 diabetes (see below).

The charity Diabetes UK estimates that around 850,000 people in England have diabetes, but haven't been diagnosed.

Many more people have blood glucose (sugar) levels above the normal range, but not high enough to be diagnosed as having diabetes. This is sometimes known as "pre-diabetes", and if you have it you have a greater risk of developing full-blown diabetes.

It's very important for diabetes to be diagnosed as early as possible, because it will get progressively worse if left untreated.

You should therefore visit your GP as soon as possible if you have symptoms, which include feeling thirsty, passing urine more often than usual and feeling tired all the time (see the list below for more diabetes symptoms).

Type 1 and type 2 diabetes

There are two main types of diabetes  type 1 and type 2.

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 is known as insulin resistance.

Type 2 diabetes is far more common than type 1 diabetes, which occurs when the body doesn't produce any insulin at all. In the UK, about 90% of all adults with diabetes have type 2. 

Type 1 diabetes usually develops before the age of 40 – often in the teenage years, while type 2 diabetes tends to be diagnosed in older people.

The danger of type 2 diabetes

The rapid rise in the number of adults developing type 2 diabetes is due to:

  • increasing levels of obesity
  • a lack of exercise
  • increase in unhealthy diets
  • an ageing population

Even if you feel healthy, you may have a higher than normal blood glucose level (pre-diabetes) and be at risk of getting the condition.

It's therefore important to take preventative measures by making any necessary lifestyle changes, such as eating more healthily, losing weight (if you're overweight) and becoming more physically active.

Read more about the lifestyle changes you can make to help treat and prevent type 2 diabetes.

Diabetes can cause serious long-term health problems. It's the most common cause of visual impairment and blindness in people of working age. It's 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 and stroke than those without diabetes.

Read more about the complications of type 2 diabetes.

Diabetes symptoms

Diabetes can cause a variety of symptoms. The main symptoms of undiagnosed diabetes include:

  • urinating frequently, particularly at night
  • feeling very thirsty
  • feeling very tired
  • unexplained weight loss and loss of muscle bulk
  • itching of the genitals or frequent episodes of thrush
  • cuts and wounds that heal slowly
  • blurred vision

The symptoms of type 2 diabetes may not be so obvious, because the condition usually develops slowly over a number of years. It may only be picked up during a routine medical check-up.

You should visit your GP as soon as possible if you notice any of the above symptoms.

You can also use the diabetes self-assessment tool on this page to find out your risk of developing type 2 diabetes.

Causes of type 2 diabetes

Insulin is a hormone produced by the pancreas – a large gland located behind the stomach.

Insulin controls the amount of glucose in your blood. It moves glucose from the blood into your cells, where it's converted into energy.

In type 2 diabetes, not enough insulin is produced to maintain a normal blood glucose level (insulin deficiency), or your body is unable to use the insulin that's produced effectively. This is known as insulin resistance.

Read more about the causes of type 2 diabetes.

At risk groups

Although all adults are at risk of developing type 2 diabetes, a number of groups have a particularly high risk of developing the condition.

Your risk of developing type 2 diabetes is increased if:

  • you're over 40 years of age (over 25 if you're South Asian)
  • you have a close family member with diabetes (a parent, brother or sister)
  • you're overweight or obese, with a waist size of over 80cm (31.5 inches) for women and 94cm (37 inches) for men, or 89cm (35 inches) for South Asian men 
  • you're of South Asian, Chinese, African-Caribbean or black African origin (even if you were born in the UK) 
  • you've ever had a cardiovascular disease, such as a heart attack or stroke
  • you're a woman with polycystic ovary syndrome (PCOS) and also overweight
  • you're a woman and you've had gestational diabetes or given birth to a baby of over 10 pounds 
  • you have a severe mental health condition, such as depression, schizophrenia or bipolar disorder, and you're taking medication for it
  • you've been told you have impaired glucose tolerance or impaired fasting glycaemia

Treating type 2 diabetes

There is no cure for diabetes. However, treatment aims to keep your blood glucose levels as normal as possible, which will control your symptoms and minimise the risk of health problems developing later on.

If you're diagnosed with diabetes, you may be referred to a diabetes care team for specialist treatment, or your GP surgery may provide first-line diabetes care.

In some cases, it may be possible to control your diabetes symptoms by making changes to your lifestyle, such as eating a healthy diet and taking regular exercise (see below).

However, as type 2 diabetes is a progressive condition, you may eventually need to take medication to keep your blood glucose at normal levels. You may need to take tablets initially, but move on to injected therapies, such as insulin, at a later stage.

Read more about treating type 2 diabetes.

Living with diabetes

If you have type 2 diabetes, you will be advised to look after your health very carefully.

Caring for your health will also make treating your diabetes easier and minimise your risk of developing complications. You should:

If you have diabetes, your eyes are at risk from diabetic retinopathy, a condition that can lead to sight loss if it's not treated. Everyone with diabetes aged 12 or over should be invited to have their eyes screened once a year. 

Read more about living with type 2 diabetes.

Gestational diabetes (during pregnancy)

Blood glucose levels can sometimes increase during pregnancy, making difficult for insulin to absorb it all. This is called gestational diabetes, which affects about 5% of pregnant women.

Gestational diabetes can increase the risk of health problems developing in an unborn baby, so it's important to keep your blood glucose levels under control.

In most cases, gestational diabetes disappears after the baby is born. However, women who develop the condition have about a 30% risk of developing type 2 diabetes in later life.

Read more about gestational diabetes.

Healthy living with diabetes

Diabetes can have serious health consequences, including heart disease and blindness. But with careful management you can reduce your risk

Page last reviewed: 18/06/2014

Next review due: 18/06/2016