Type 2 diabetes is a progressive condition in which the body becomes resistant to the normal effects of insulin and/or gradually loses the capacity to produce enough insulin in the pancreas. We do not know what causes type 2 diabetes. Type 2 diabetes is associated with modifiable lifestyle risk factors. Type 2 diabetes also has strong genetic and family related risk factors.

Type 2 diabetes:

• Is diagnosed when the pancreas does not produce enough insulin (reduced insulin production) and/or the insulin does not work effectively and/or the cells of the body do not respond to insulin effectively (known as insulin resistance)
• Represents 85–90 per cent of all cases of diabetes
• Usually develops in adults over the age of 45 years but is increasingly occurring in younger age groups including children, adolescents and young adults
• Is more likely in people with a family history of type 2 diabetes or from particular ethnic backgrounds
• For some the first sign may be a complication of diabetes such as a heart attack, vision problems or a foot ulcer
• Is managed with a combination of regular physical activity, healthy eating and weight reduction. As type 2 diabetes is often progressive, most people will need oral medications and/or insulin injections in addition to lifestyle changes over time.

What happens with type 2 diabetes?

Type 2 diabetes develops over a long period of time (years). During this period of time insulin resistance starts, this is where the insulin is increasingly ineffective at managing the blood glucose levels. As a result of this insulin resistance, the pancreas responds by producing greater and greater amounts of insulin, to try and achieve some degree of management of the blood glucose levels.

As insulin overproduction occurs over a very long period of time, the insulin producing cells in the pancreas wear themselves out, so that by the time someone is diagnosed with type 2 diabetes, they have lost 50 – 70% of their insulin producing cells. This means type 2 diabetes is a combination of ineffective insulin and not enough insulin. When people refer to type 2 diabetes as a progressive condition they are referring to the ongoing destruction of insulin producing cells in the pancreas.

Initially, type 2 diabetes can often be managed with healthy eating and regular physical activity. Over time most people with type 2 diabetes will also need tablets and many will eventually require insulin. It is important to note that this is the natural progression of the condition, and taking tablets or insulin as soon as they are required can result in fewer long-term complications.

What causes type 2 diabetes?

Diabetes runs in the family. If you have a family member with diabetes, you have a genetic disposition to the condition.

While people may have a strong genetic disposition towards type 2 diabetes, the risk is greatly increased if people display a number of modifiable lifestyle factors including high blood pressure, overweight or obesity, insufficient physical activity, poor diet and the classic ‘apple shape’ body where extra weight is carried around the waist.

People are at a higher risk of getting type 2 diabetes if they:

• have a family history of diabetes
• are older (over 55 years of age ) - the risk increases as we age
• are over 45 years of age and are overweight
• are over 45 years of age and have high blood pressure
• are over 35 years of age and are from an Aboriginal or Torres Strait Islander background
• are over 35 years of age and are from Pacific Island, Indian subcontinent or Chinese cultural background
• are a woman who has given birth to a child over 4.5 kgs (9 lbs), or had gestational diabetes when pregnant, or had a condition known as Polycystic Ovarian Syndrome.

Check your risk – answer 10 short questions on the diabetes risk calculator.

Read our section on preventing type 2 diabetes.

Symptoms

Many people with type 2 diabetes display no symptoms. As type 2 diabetes is commonly (but not always) diagnosed at a later age, sometimes signs are dismissed as a part of ‘getting older’. In some cases, by the time type 2 diabetes is diagnosed, the complications of diabetes may already be present.

Symptoms include:

• Being excessively thirsty
• Passing more urine
• Feeling tired and lethargic
• Always feeling hungry
• Having cuts that heal slowly
• Itching, skin infections
• Blurred vision
• Gradually putting on weight
• Mood swings
• Headaches
• Feeling dizzy
• Leg cramps