Type 2 diabetes

High blood glucose levels occur in diabetes because the body does not respond properly to the hormone insulin, which controls glucose levels.

In type 2 diabetes, insulin is less effective in controlling blood glucose levels. This is because the key targets of insulin, liver and muscle cells, are less sensitive to its effects. This condition is termed ‘insulin resistance’.

Insulin resistance may be triggered by chronic inflammation. This is caused by immune cells within fat tissue releasing substances that inflame neighbouring tissues. The fatter a person becomes, the more inflammation their fat tissue generates.

Insulin resistance leads to high levels of glucose in the blood. This can reinforce insulin resistance, potentially by exacerbating inflammation. At the same time, high levels of glucose in the blood trigger more insulin release from the pancreas. This triggers inflammation within the pancreas, which kills the insulin-secreting beta cells. This leads to less insulin being produced, worsening the blood glucose levels and increasing inflammation.

Around 1.3 million Australians have been diagnosed with type 2 diabetes. It is estimated that another 500,000 Australians have the condition but have not been diagnosed, putting them at increased risk of complications. Complications of type 2 diabetes are a significant health burden for Australia.

A person’s risk of developing type 2 diabetes depends on their age and their genetic makeup, but also on ‘lifestyle’ factors.

Certain inherited, genetic factors increase a person’s chances of developing type 2 diabetes. This explains why relatives of someone with type 2 diabetes are more likely to also have this condition. It also explains why type 2 diabetes rates are higher in people from certain racial and ethnic groups. Aboriginal Australians have a high risk of developing type 2 diabetes.

A person’s chances of developing type 2 diabetes are increased if they:

• Are older: type 2 diabetes risk increases with age
• Are overweight or obese
• Have high blood pressure
• Have previously had gestational diabetes
• Are female

Reducing body weight and increasing physical fitness can reduce a person’s chances of developing type 2 diabetes.

The severity of type 2 diabetes can differ between people. Some people show insulin resistance but normal levels of insulin production; in other people, the condition is predominantly associated with reduced insulin production. These factors can also change with time.

The severity and characteristics of a person’s type 2 diabetes influences how they are treated. Blood glucose levels can often be controlled by regular exercise and eating a healthy diet, which does not raise blood sugar rapidly.

Our researchers are trialing whether weight loss can be used as a treatment for type 2 diabetes.

Some people with type 2 diabetes also require medications that:

• Reduce blood sugar levels.
• Improve how cells respond to insulin.
• Stimulate insulin production by the pancreas.

When insufficient insulin is produced, a person with type 2 diabetes needs to start taking additional insulin. This is given by injections or through a pump.

In the long term, people with type 2 diabetes may need additional treatments for complications of their condition. Common complications of type 2 diabetes include:

• Kidney disease (diabetic nephropathy)
• Eye disease and blindness (diabetic retinopathy)
• Nerve damage (diabetic neuropathy)
• Damage to blood vessels, which together with nerve damage can lead to serious problems in the hands and feet
• Heart disease and stroke.

For more information, and support for people with type 2 diabetes please visit Diabetes Australia.