diabetes mellitus, NIDDM (non insulin-dependent diabetes mellitus)

What is type 2 diabetes?

Type 2 diabetes develops when your body stops producing enough of the hormone insulin (insulin deficiency) or when your body becomes less responsive to the insulin your body does produce (insulin resistance).

Insulin is an important hormone - it is made by your pancreas and released into your blood. Insulin allows the sugar (glucose) in your bloodstream to enter your body's cells and be burned as fuel. Glucose is derived from carbohydrates (starchy foods) in your diet, and is a source of energy.

In type 2 diabetes, the lack of insulin action means glucose cannot move from the blood into cells (such as muscle cells) to be burned or stored, so the blood glucose builds up to levels that are harmful.

Type 2 diabetes can be controlled for many years if you take steps to avoid high levels of blood glucose - this is done through lifestyle and diet changes and measuring your own blood glucose level. Type 2 diabetes is a progressive condition, so medications may be needed later on.

How common is type 2 diabetes?

Type 2 diabetes is the most common form of diabetes. In New Zealand, about 110,000 people have type 2 diabetes, and this number is rising rapidly in line with the increasing rates of obesity in all age groups.

People aged over 30 years from Maori, Polynesian or Asian backgrounds, Europeans aged over 40 years, people who are overweight (especially around the belly), have high blood pressure or exercise very little, people with type 2 diabetes in blood relatives and women who have had diabetes in pregnancy or women who have had a baby weighing more than 4kg are also all at higher than average risk.

How do I know if I have type 2 diabetes?

Having high blood glucose levels can cause you:

• to feel very tired
• to feel extremely thirsty
• to need to urinate frequently
• to have blurred vision
• to get frequent skin, mouth, throat or bladder infections
• to feel cramps or burning in your feet or legs.

About half of all those with diabetes are thought to be undiagnosed cases; these people may have no symptoms. Therefore, if your doctor suspects diabetes he or she will arrange a blood test for glucose levels (you may need to fast overnight) and possibly blood lipid (cholesterol) levels as well.

What can be done about my diabetes?

There is no cure as such. The aim is to control your blood glucose level throughout each and every day.

The most important thing you can get from your doctor and diabetes nurse/educator is a good understanding about diabetes - ultimately you will be in charge of the day-to-day management of your diabetes. Your doctor is there to help you stay on course with an agreed plan and carry out the free annual diabetes check-ups you are entitled to. The key parts of your plan will be:

• reaching a healthy weight by starting an exercise programme approved by your doctor - sustained exercise that makes you breathe a bit harder also lowers your blood glucose, blood cholesterol and your blood pressure
• eating a "diabetes-friendly" diet - Diabetes New Zealand has good diet leaflets; call 0800 342 238
• testing your own blood glucose levels regularly
• not smoking - diabetes already raises your heart risk
• understanding your medication and using it correctly.

Some people are able to regain control of their blood glucose levels through diet change, weight loss and regular exercise. This does not mean the diabetes is cured, you have just gained control of it. If you have high blood glucose levels this also means you are at much higher risk for heart disease, so gaining control in this way is also good for your heart.

Blood glucose testing

Home testing kits use a pinprick of your blood to give you a "snapshot" blood glucose reading almost instantly (the normal range for a healthy person is 4 to 7 mmol/L, which is what you should be aiming for). Measuring your blood glucose at set times of the day and around mealtimes gives you an idea of how well you have your diabetes under control and, if you are taking medications, how well they are working. Your doctor or diabetes nurse can explain how to test yourself properly.

Your doctor will also arrange a laboratory blood glucose test, called a HbA1c test, every three to six months. This gives a more reliable reading - a three-month average - of how well you've had your diabetes under control (ideally, your HbA1c should be 7% or less). These regular visits are a good opportunity to ask questions and review your lifestyle changes.

If these lifestyle changes do not lower your blood glucose sufficiently, or you have other health problems as well, your doctor may suggest you take tablets to improve the way your body handles glucose. The three main types of tablets are sulphonylurea drugs, metformin and the glitazone drugs. Finding one that suits you and finding the right dose may be the added help you need.

It is important to note that drugs of the sulphonylurea type, if used at the wrong time, during heavy exercise, with alcohol or without eating sufficient food, can cause a 'hypo' - a drop in blood glucose to dangerously low levels.

Warning signs of a 'hypo' vary but include dizziness, hunger, confusion, blurred vision and nausea. It is important you always carry glucose sweets to chew (immediately after checking your blood glucose level) otherwise you are at risk of passing out into a coma through lack of glucose reaching the brain.

Problems of uncontrolled diabetes

There are some debilitating effects caused by diabetes when it is allowed to run uncontrolled for many years. These result from the damage to blood vessels and nerves caused by high blood glucose levels and can include numbness and circulation problems in the feet causing serious ulcers and the possible need for amputations; loss of vision through damage to the retina; impotence in men; kidney damage and possible kidney failure requiring dialysis; and heart disease and stroke.

These are worrying prospects but they can largely be avoided if you take a positive approach to keeping your blood glucose under control and seek help from your doctor and diabetes nurse.

Original material provided by everybody. Reviewed October 2005.