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Diabetes mellitus is a chronic disease that significantly affects the health of Australians. It may lead to a range of complications which can cause disability, and reduce people’s quality of life and life expectancy. Diabetes is responsible for an enormous public health and social burden, and is one of the top 10 causes of death in Australia.

Diabetes is a long-term (chronic) condition in which the body loses its ability to control the level of glucose (sugar) in the blood. Insulin is a hormone produced by special cells in the pancreas that helps the body to convert glucose from food into energy. People with diabetes either don’t have enough insulin or their body cannot use insulin effectively, so glucose stays in the blood instead of being turned into energy, causing blood sugar levels to become high. Different insulin abnormalities cause different types of diabetes. Four main types of diabetes exist: type 1 diabetes, type 2 diabetes, gestational diabetes and other diabetes.

Type 1 diabetes

Type 1 diabetes mainly occurs in children or young adults, although it can occur at any age. In type 1 diabetes the body stops making insulin. Without insulin, the body cannot turn glucose (sugar) into energy so it burns its own fats as a substitute. Unless treated with insulin, people with type 1 diabetes accumulate dangerous chemicals in their blood from the burning of fat, causing a condition known as ketoacidosis. This condition is potentially life-threatening if not treated.

Most cases of type 1 diabetes are caused by the destruction of the insulin-producing cells in the pancreas by the body’s immune system. According to self-reported data from the 2007–08 National Health Survey, around 10% of people with diabetes have this form of the disease.

Type 2 diabetes

Type 2 diabetes is the most common form of diabetes. It occurs mostly in people aged 50 years and over and, although still uncommon in childhood, it is becoming increasingly diagnosed in younger people. People with type 2 diabetes produce insulin, but cannot use it effectively or may not produce enough. Type 2 diabetes may initially be managed with changes to diet and exercise, and/or oral glucose-lowering drugs. People with type 2 diabetes may progress to needing insulin or a combination of these therapies if their condition cannot be managed through lifestyle changes and/or oral drugs. Type 2 diabetes accounts for 87% of all people with diabetes, according to self-reported data from the 2007–08 National Health Survey.

Gestational diabetes mellitus

Gestational diabetes mellitus is a form of diabetes that can develop during pregnancy. It involves high blood sugar levels appearing for the first time during pregnancy in women not previously diagnosed with other forms of diabetes. This type of diabetes is short term and, although it usually disappears after the baby is born, it can recur in later pregnancies. Gestational diabetes is also a marker of increased risk of developing type 2 diabetes later in life. Some cases of gestational diabetes are managed with changes to diet and exercise, and some require insulin treatment. About 5% of pregnant women are affected.

Other types of diabetes

Other types of diabetes can occur as a result of other conditions or syndromes, such as:

  • genetic defects of beta-cell function in the pancreas and insulin action
  • other diseases of the pancreas (including cystic fibrosis and cancer of the pancreas)
  • endocrine disorders (for example, acromegaly and Cushing’s Syndrome)
  • drug- or chemical-induced diabetes (for example, steroid-induced diabetes)
  • infections (for example, congenital rubella)
  • uncommon but specific forms of immune-mediated diabetes mellitus
  • other genetic syndromes sometimes associated with diabetes.

Around 3% of people are affected by other types of diabetes.

Impaired glucose regulation

Impaired glucose regulation, or intermediate hypeglycaemia, is the metabolic state between normal glucose regulation and the state of failed regulation known as diabetes. There are two categories of impaired glucose regulation:

  • impaired fasting glucose (IFG), and
  • impaired glucose tolerance (IGT).

IFG and IGT are considered risk factors for the future development of diabetes and cardiovascular disease.

Further information

AIHW 2011. Prevalence of Type 1 diabetes in Australian children, 2008

AIHW 2011. Diabetes prevalence in Australia: Detailed estimates for 2007–08

AIHW 2010. Australia’s health 2012

AIHW 2010. Diabetes in pregnancy: its impact on Australian women and their babies

AIHW 2009. Prevention of cardiovascular disease, diabetes and chronic kidney disease: targeting risk factors

AIHW 2008. Diabetes, Australian facts 2008