Diabetes - pre-diabetes

What is pre-diabetes?

Pre-diabetes, which may be known as Impaired Glucose Tolerance (IGT) or Impaired Fasting Glucose (IFG), occurs when blood glucose levels are higher than normal, although not high enough to be diabetes. There are no symptoms. People with pre-diabetes have a higher risk of developing type 2 diabetes and cardiovascular (heart and circulation) disease.

Without lifestyle changes, approximately one in 3 people with pre-diabetes will develop type 2 diabetes. Lifestyle changes such as exercise, healthy eating and weight loss (if you are overweight) will help reduce your risk of type 2 diabetes.

What is diabetes?

Blood glucose levels are regulated by a hormone in the body called insulin. Insulin moves glucose from the blood into the cells for energy. 

Diabetes is a condition where glucose in the blood is too high. This happens when the pancreas can no longer make insulin as in type 1 diabetes. In type 2 diabetes the pancreas cannot make enough insulin and the insulin it makes does not work as well as it should (also known as insulin resistance). As a result glucose in the blood rises above ideal levels. 

Type 2 diabetes can be managed through lifestyle changes such as healthy eating, exercise, weight loss (if overweight) and diabetes medication. Management for both type 1 and 2 diabetes aims to reduce the risk of health problems such as damage to blood vessels and nerves.

If not well managed, diabetes can lead to heart attack or stroke. Other parts of the body that can be damaged by diabetes are the eyes, kidneys, feet and nerves. 

Pre-diabetes usually has no  symptoms, so it is important to be aware of the risk factors and have regular checks by your doctor. 

Risk factors for pre-diabetes

The risk factors for developing pre-diabetes are the same as for type 2 diabetes. They include: 

• family history of type 2 diabetes 
• being overweight 
• waist measurement
  • in Caucasian men – greater than 94 cm
  • in Asian men – greater than 90 cm
  • in women – greater than 80 cm
• low level of physical activity
• smoking
• high blood pressure or high cholesterol (blood fats), or both
• gestational diabetes (diabetes during pregnancy)
• polycystic ovary syndrome
• some antipsychotic medications.

Also, the risk of developing pre-diabetes is greater for:

• Aboriginal and Torres Strait Islander people
• Middle Eastern people
• South Asian people
• Pacific Islander people
• North African people.

Diagnosis of pre-diabetes

Pre-diabetes is diagnosed by a pathology blood test, organised through your doctor, that checks your blood glucose level.

Any blood glucose test that shows higher than normal blood glucose levels needs to be checked further. An oral glucose tolerance test (OGTT) is the best way to diagnose pre-diabetes. The results of the OGTT will show whether your blood glucose levels are in the normal, pre-diabetes or diabetes range. 

If you are diagnosed with pre-diabetes, you will have one or both of: 

• impaired fasting glucose (IFG) – when your fasting blood glucose level is higher than optimal, but still below the level needed for a diagnosis of diabetes
• impaired glucose tolerance (IGT) – when your blood glucose level 2 hours after an OGTT is higher than optimal, but is still below the level needed for a diagnosis of diabetes. The fasting blood glucose level may be in the target range.

Management of pre-diabetes

Pre-diabetes, type 2 diabetes and heart disease can be prevented by making lifestyle changes, including:

• Weight loss – helps the insulin in your body work better and lower your blood glucose levels.
• Regular moderate physical activity – exercise makes your insulin work better. It will  help lower your blood glucose, blood pressure and cholesterol levels. Exercise also helps you manage your weight.
• A healthy diet – eat less saturated fats and more healthy fats (nuts, avocado, oily fish, olive oil), fruit, vegetables and high-fibre wholegrain foods.
• Stopping smoking – smoking causes insulin resistance and increases the risk of blood vessel disease.
• Blood pressure and cholesterol control – should be well managed and checked regularly by your doctor.

In many cases, if enough lifestyle changes are made, type 2 diabetes can be prevented.

Follow-up for pre-diabetes

You don’t need to check your own blood glucose levels with a blood glucose meter when you have pre-diabetes. 

Once you are diagnosed with pre-diabetes, lifestyle changes are most important. Your doctor should organise a repeat oral glucose tolerance test in 12 months, unless you develop symptoms of diabetes earlier. If you do have some of the symptoms of diabetes then it is important to speak to your doctor about this.

Where to get help

• Your GP (doctor)
• Community health centre
• National Diabetes Services Scheme (NDSS) Helpline Tel. 1800 637 700
• Diabetes Victoria Tel. 1300 437 386
• Life! Helping you prevent diabetes, heart disease and stroke  Tel.13 74 75
• Dietitians AustraliaTel. 1800 812 942