Type 2 Diabetes

About type 2 diabetes 

Type 2 diabetes is also known as non-insulin-dependent diabetes mellitus.

Glucose and insulin

Glucose is a simple form of sugar found in foods and sugary drinks - it's absorbed as a natural part of digestion.

One function of your blood is to carry glucose around your body. When glucose reaches body tissues, such as muscle cells, it's absorbed and converted into energy. Insulin helps with the absorption process so it's critical for regulating the glucose concentration. If you have a shortage of insulin, glucose can build up in your blood.

Insulin is secreted into the blood by your pancreas - a gland that also produces digestive juices and is found behind your stomach. If your cells don't respond properly to insulin, this can cause glucose to build up in your blood. This is called insulin resistance. You can develop this if you're overweight or type 2 diabetes runs in your family. Having insulin resistance means your pancreas needs to produce more and more insulin to control blood glucose levels. Eventually your body can't produce enough insulin so your levels rise and diabetes develops.

Types of diabetes 

There are two main types of diabetes: type 1 and type 2. Almost 900,000 Australians have diabetes.

Type 2 diabetes is more common, affecting about 90 percent of Australians with diabetes.

Symptoms of type 2 diabetes 

Many people with type 2 diabetes have no symptoms, and it's often discovered accidentally after routine medical check-ups or following screening tests for other conditions.

If you do have symptoms of type 2 diabetes, they might include:

• excessive passing of urine
• constant thirst
• tiredness
• blurred vision
• itchy skin around your genitals or regular infections, such as thrush.

You may also have noticed a change in your weight over recent months. You may have gained weight (causing diabetes) or lost weight as a result of high blood glucose levels. It's also possible that your weight hasn't changed at all.

Your symptoms may be very mild and can go unnoticed for years.

Complications of type 2 diabetes 

Long-term complications of type 2 diabetes are similar to those of type 1 diabetes.

These include:

• angina
• heart attack
• stroke
• diabetic kidney damage
• diabetic foot ulcers or circulation problems in your legs and feet
• diabetic eye damage - if diagnosed and treated, blindness can usually be prevented.

You'll need to have annual check-ups to monitor whether you've developed any complications.

Rarely, if a severe infection occurs or type 2 diabetes isn't diagnosed or is poorly controlled, people with the condition can develop hyperosmolar non-ketotic coma (HONK).

HONK is caused if blood sugar rises to very high levels. It causes:

• extreme thirst
• nausea (feeling sick)
• dry skin
• excessive urine production
• disorientation.

Eventually it can cause drowsiness and loss of consciousness. HONK needs to be treated in hospital.

In the long term, uncontrolled high blood glucose (hyperglycaemia) can be very damaging to your health and can increase your risk of heart disease, stroke, kidney failure, nerve damage and blindness.

Causes of type 2 diabetes 

Type 2 diabetes develops when your body becomes resistant to insulin. This happens when your body's tissues don't respond well to insulin and so can't make use of the glucose in the blood for energy. Your pancreas responds by producing more insulin and your liver, where glucose is stored, releases more glucose.

Eventually your pancreas becomes less able to produce enough insulin and your tissues become more resistant to insulin. As a result, blood glucose levels slowly start to rise.

It can take several years for blood glucose to reach a level that causes symptoms of type 2 diabetes.

You're more likely to develop type 2 diabetes if you:

• are overweight or obese
• don't exercise very often
• have a family history of type 2 diabetes
• smoke
• drink alcohol excessively
• are of Aboriginal and Torres Strait islander origin – these people have a three times higher risk of developing diabetes compared to the rest of the population origin
• are over 40 and Caucasian - the risk increases further with age
• have high blood pressure or have had a heart attack or stroke
• have polycystic ovary syndrome (PCOS) and are overweight
• have impaired glucose tolerance.

Diagnosis of type 2 diabetes 

If you think you may be developing diabetes, visit your GP. Your GP will ask about your symptoms and examine you. He or she may also ask you about your medical history.

You may also be asked to have a blood test to measure the level of glucose in your blood. This might be a fasting glucose test, which is taken after you haven't eaten for at least eight hours, or a random glucose test done at any time.

If your GP can't make a definite diagnosis after these tests, you may have a glucose tolerance test. This measures how your blood glucose level changes over time after you swallow a sugary drink. Before having this test, you'll need to fast overnight.

Your care will probably be managed by your GP. However, you may be referred to a specialised diabetes clinic.

Treatment of type 2 diabetes 

Some people with type 2 diabetes can initially control their condition with lifestyle changes alone.

Self-help

• Diet. A healthy diet is essential if you have diabetes and it's important to eat regularly three times a day. Special diabetic foods aren't necessary for a healthy diet; you just need to eat a balanced diet that is low in saturated fat, sugar and salt, and high in fibre, vegetables and fruit. Include carbohydrates, such as pasta, potatoes or sugary foods such as fruit in each meal. Your GP, dietitian/nutritionist or diabetes educator can help you design a healthy eating plan.
• Exercise. Exercise promotes a healthy circulation and will help you to stay a healthy weight. At least half an hour of moderate activity on at least five days a week can help you lose weight.
• Smoking. Smoking is unhealthy for everyone, but quitting is especially important for people with diabetes. This is because you already have an increased chance of developing cardiovascular disease or circulatory problems. Smoking makes the chances of developing these diseases even greater.
• Alcohol. If you have diabetes, there's no need to give up alcohol completely, but it's important to drink sensibly. It is recommended to drink no more than two standard drinks each day. However, don't drink on an empty stomach - eat food containing carbohydrate before and after drinking and monitor your blood glucose levels regularly.

Medicines

If lifestyle changes alone don't reduce your glucose levels, you may be prescribed medicines to increase insulin production and strengthen its effect. Some examples are listed below:

• Metformin. This improves the effectiveness of insulin by reducing the amount of glucose released from the liver and improving the way glucose is used by muscles.
• Sulfonylureas. These medicines encourage your pancreas to produce more insulin, and examples include glibenclamide and glipizide.
• Prandial glucose regulators. These medicines also encourage your pancreas to produce more insulin - they work more quickly than sulfonylureas but only last for a short time. An example is repaglinide.
• Glitazones. These medicines reduce your body's resistance to insulin and are sometimes used with metformin and sulfonylureas if other standard treatments aren't working or aren't tolerated. Examples include rosiglitazone and pioglitazone.
• DPP-4 inhibitors. These are newer medicines that help your body to produce more insulin in response to meals. They don't cause weight gain and only rarely cause hypos. Examples are as sitagliptin or vildagliptin.
• Alpha-glucosidase inhibitor. This is a medicine called acarbose that lowers blood glucose by slowing the breakdown of some carbohydrates.

Two or more of the medicines listed here can be given in combination as they may give better control than one on its own. Your doctor and diabetes educator can advise on which treatments are most appropriate for you.

It's very important to keep your blood pressure and the level of cholesterol in your blood well controlled. High blood pressure and high cholesterol levels have been linked to heart attack and stroke - you're more at risk of these and other complications if you have diabetes.

It's important to try to lower your cholesterol levels through lifestyle measures such as changing your diet, losing excess weight and taking regular exercise. However, if these don't work, you're likely to be prescribed a medicine to help lower your cholesterol.

You may also be given medicines to control your blood pressure if lifestyle changes including those mentioned above aren't enough to do this.

Insulin injections

If lifestyle changes and oral medicines don't control your blood glucose levels, you may need to start insulin injections in addition to, or instead of, tablets.

You will usually give insulin injections to yourself once or twice a day, using either a traditional needle or a pen-type syringe with refillable cartridges. There are different kinds of insulin that work at different rates and for different lengths of time. Each can have varying rates of success in different people - ask your doctor for advice on which type is best for you.

Monitoring your blood sugar

You may be able to monitor your blood glucose levels with a home test kit. This involves taking a pinprick of blood from your finger and putting a drop on a testing strip. A meter will read the result automatically. However, self-monitoring isn't usually recommended unless you're using insulin injections. More research is needed to find out whether self-monitoring is an effective way of controlling blood glucose.

You can adjust both your diet and insulin to keep your blood glucose level within the normal range. Your 'normal' range will be specific to you but a general guide for adults is:

• before meals: 4 to 7 mmol/L
• after meals: less than 8.5 mmol/L.

Your GP or diabetes educator can guide you on how to monitor and manage your blood glucose and will give you continuing support.

Further information 

Diabetes Australia
www.diabetesaustralia.com.au

Sources 

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Last published: 30 July 2011.

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