Diabetes - 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 signs or 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 three 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.

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 the pancreas cannot make enough insulin or the insulin it makes does not work as well as it should (also known as insulin resistance) so glucose in the blood rises above optimal levels. 

Type 2 diabetes is a combination of insulin not working properly and not enough insulin being made. It can be managed through lifestyle changes such as healthy eating, exercise, weight loss (if overweight) and diabetes medication. Management 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 has no signs or 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: 

• a 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
• history of heart disease or stroke
• 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 two 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 – will help you manage your weight and will also lower your blood glucose, blood pressure and cholesterol levels. Exercise also makes your insulin work better
• a healthy diet – this involves less fat, especially saturated fats, and more 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.

Where to get help

• Your doctor
• Community health centre
• Diabetes Victoria Tel. 1300 437 386
• Life! Helping you prevent diabetes, heart disease and stroke  Tel.13 7475
• Dietitians Association of Australia Tel. 1800 812 942