Diabetes mellitus occurs when the level of sugar (glucose) in the blood becomes higher than normal. There are two main types  type 1 and type 2 diabetes.

Type 1 diabetes This type usually develops quite quickly, over days or weeks, as the pancreas stops making insulin. Type 1 diabetes usually first presents in childhood.

Type 2 diabetes This is more common in people who are overweight or obese. Type 2 diabetes tends to develop gradually (over weeks or months). This is because people with type 2 diabetes still make insulin (unlike type 1 diabetes). However, people with type 2 diabetes do not make enough insulin for the body's needs, or the body is not able to use insulin properly. Type 2 diabetes usually starts in middle-aged or elderly adults but is increasingly being seen in children and in young adults.

Gestational diabetes Pregnant women who have never had diabetes before but who have high blood glucose levels during pregnancy are said to have gestational diabetes.

What are the symptoms of diabetes?

The symptoms when you first develop diabetes may include:

  • Being very thirsty a lot of the time.
  • Passing a lot of urine.
  • Tiredness, weight loss and feeling generally unwell.

The symptoms tend to develop quite quickly  with type 1 diabetes. While the symptoms develops much more slowly and symptoms may not start until you have had type 2 diabetes for a number of years. This means that people with type 2 diabetes may already have complications of diabetes when diabetes is first diagnosed.

How is diabetes diagnosed?

Have a blood test to look at the level of glucose in your blood. If this is high then it will confirm that you have diabetes.

Some people have to have two samples of blood taken and they may be asked to fast (this means having nothing to eat or drink, other than water, from midnight before the blood test is performed). A different blood test which measures a chemical called HbA1c is now also used to diagnose type 2 diabetes but is not suitable for the diagnosis of type 1 diabetes. tells you your average level of blood sugar over the past 2 to 3 months.

When you are unwell for any reason, even just a sore throat, this may badly affect your blood glucose control. It is therefore very important to know what to do if you are unwell.

How is diabetes treated?

Any person with diabetes needs to follow a healthy lifestyle with a healthy diet, maintaining an ideal body weight, taking regular exercise and not smoking. People with type 1 diabetes also always need treatment with insulin.

People with type 2 diabetes sometimes don't need any medicines for diabetes control when the diagnosis is first made. However, most people with diabetes need to start taking one or more medicines if a healthy lifestyle is not enough to control blood sugar (glucose) levels.Some people with type 2 diabetes need to use insulin injections if the other medicines don't adequately control the blood glucose levels.

Treating diabetes is not just about blood glucose levels. It is also very important to reduce the risk of the complications of diabetes (see below). It is therefore important to keep blood pressure and cholesterol levels in the normal range.

The treatment for diabetes also includes regular monitoring to diagnose and treat complications at an early stage.

Diabetes in pregnancy is associated with possible problems for the mother and baby. Women with diabetes who become pregnant need very close monitoring and specialist treatment to make sure that the mother and baby remain well with no problems.


Healthy diet and other lifestyle advice

You should eat a healthy diet. Basically, you should aim to eat a diet low in fat, salt and sugar and high in fiber, and with plenty of fruit and vegetables.

Smoking is a high risk factor for complications. Regular physical activity also reduces the risk of some complications such as heart and blood vessel disease. If you are able, a minimum of 30 minutes' brisk walking at least five times a week is advised. Anything more vigorous is even better - for example, swimming, cycling, jogging, dancing. Depending on your age and how long you have had diabetes, you may be advised to take a medicine to lower your cholesterol level. This will help to lower the risk of developing some complications such as heart disease and stroke. Try to lose weight if you are overweight or obese. Excess weight is also a risk factor for heart and blood vessel disease.

Many people with diabetes enjoy alcohol and there is no need to give up completely unless you wish to. However, do be aware that drinking alcohol when you have diabetes can make an episode of hypoglycaemia (a 'hypo') more likely.


Anyone with diabetes who needs treatment with insulin should monitor their blood glucose levels. This is usually not necessary for people with type 2 diabetes who do not need insulin. It is important to have regular checks, as some complications, particularly if detected early, can be treated or prevented from becoming worse. Regular Checking levels of blood glucose, HbA1c, cholesterol and blood pressure is important. Checking for early signs of complications like to detect problems with the retina, kidney function, Urine, Foot checks - to help to prevent foot ulcers, Tests for the sensation in your legs to detect early nerve damage are also important.

What are the possible complications of diabetes?

If your blood sugar (glucose) levels are not well controlled this may cause a lack of fluid in the body (dehydration), tiredness and drowsiness. This may progress to a serious illness which can be life-threatening, especially if you have type 1 diabetes. Less commonly, people with type 2 diabetes may develop a condition with very high blood glucose levels but no ketones (called hyperosmolar hyperglycaemic coma).

Too much insulin can make the blood glucose level go too low (hypoglycaemia, sometimes called a 'hypo'). This can cause you to feel sweaty, confused and unwell; you may lapse into a coma. Emergency treatment of hypoglycaemia is with sugar, sweet drinks, or a glucagon injection (a hormone which has the opposite effect to insulin). Then you should eat a starchy snack such as a sandwich.

Other complications includes repeated infections, and increase the time required for controlling infection.

If the blood glucose level is higher than normal(even a mildly increased glucose level), over a long period of time, can have a damaging effect on the blood vessels. This may lead to hardening of the arteries causing angina, heart attack and stroke, Eye problem affecting vision, kidney damage, nerve damage, foot problems, sexual dysfunctions etc.

Diabetes can also cause a lot of psychological difficulties such as depression, anxiety and eating disorders.

What is the outlook?

Although diabetes is associated with serious complications, these complications can be prevented or greatly reduced in severity. A healthy lifestyle, regular monitoring and taking medicines to keep your blood sugar (glucose), blood pressure and cholesterol levels as normal as possible are all very important.

Some people with type 2 diabetes are able to achieve 'diabetes in remission'. This means their blood glucose stays within normal levels without medication. The most successful way to achieve this is with lifestyle changes, including losing weight and either a medically supervised very low-calorie diet or a low-carbohydrate diet.

Can diabetes be prevented?

There is currently no known way to prevent type 1 diabetes although many studies are looking into a number of different possibilities.

Type 2 diabetes can be prevented by following a healthy lifestyle, such as a healthy diet, regular exercise and not being overweight