What is Diabetes?

Diabetes is a condition characterised by high levels of glucose (or sugar) in the blood. When a person has a high blood sugar level they are said to be hyperglycaemic.

Glucose is essential for providing the body with energy. The body converts many of the foods that we eat into glucose. A hormone called insulin is required to transfer glucose from the bloodstream to the body’s cells.

If you suspect or know you have diabetes it is important to speak with your doctor to seek testing and advice on how to best manage your diabetes.

What is the Cause of Diabetes?

Diabetes occurs when there is not enough insulin to help get the glucose out of the bloodstream and into the body’s cells.

All types of diabetes lead to high blood glucose levels. The most common are Type 2 Diabetes Mellitus, Type 1 Diabetes Mellitus and Gestational Diabetes Mellitus. Each diabetes type has a different cause. (please see “What are the types of diabetes”).

 High blood glucose levels usually occur because:

  • The pancreas is unable to produce any or enough insulin. This happens in Type 1 Diabetes Mellitus


  • The body’s cells are resistant to the action of insulin (insulin resistance). This occurs in Type 2 Diabetes Mellitus

What Part Does the Pancreas Play in Diabetes?

The pancreas is a leaf-shaped gland located behind the stomach. It is responsible for the production of insulin, which is the hormone that helps regulate blood glucose levels.

After a meal, the blood glucose level rises, causing the pancreas to normally release insulin into the blood. In a healthy person, the insulin allows the body’s cells to absorb glucose so it can be used as energy. When there is enough insulin, the blood sugar levels stay in the normal range.

For people living with diabetes, there are two main reasons why the blood sugar levels are high. This is because either:

  1. Little or no insulin is produced by the pancreas, or
  2. The body’s cells are resistant to the action of insulin.

This results in glucose being unable to enter the cells and therefore we see increased blood glucose levels (sometimes known as hyperglycaemia).

What are the Types of Diabetes?

Type 1 Diabetes Mellitus:

Type 1 Diabetes Mellitus is caused by an autoimmune condition, where a person’s own immune system attacks the cells of the pancreas which produce insulin. This leads to very low levels of insulin. Its onset is often sudden and without warning. There is currently no way of preventing it and no cure. People living with Type 1 Diabetes Mellitus do not produce any insulin and need insulin treatment to survive. This insulin can be given either by multiple injections per day or via an insulin pump.

Type 1 Diabetes accounts for around 10% of all diagnosed cases of diabetes.

People living with Type 1 Diabetes Mellitus can lead a normal, long and healthy life with the right support of family, friends, medical team along with medications, insulin and new technology.

Another term for Type 1 Diabetes Mellitus is Juvenile Diabetes – however adults can also develop Type 1 Diabetes Mellitus.

Type 2 Diabetes Mellitus:

Type 2 Diabetes Mellitus is caused by the inability of the pancreas to produce enough insulin and/or the body’s cells being resistant to the action of insulin. It is the most common type and accounts for around 85-90% of all diagnoses of diabetes.

Type 2 diabetes is a condition that gradually progresses over time.

While there is no cure for the condition, it can be managed. People with Type 2 diabetes can lead normal, healthy and happy lives.

Lifestyle changes, such as exercising and improving your diet, are effective ways to treat Type 2 Diabetes Mellitus. People with Type 2 Diabetes Mellitus may also need medications to treat their condition depending on the severity of the condition. Along with lifestyle changes the medications may be a combination of tablets and/or injections.

MODY (Maturity Onset Diabetes of the Young):

MODY is caused by a single abnormal gene. It accounts for approximately 1-2% of all diabetes diagnoses and is caused by a genetic mutation that is often passed down in families.It is a rare form of diabetes that is different to Type 1 and Type 2 Diabetes Mellitus.

People with MODY are often diagnosed before the age of 25.

The treatment is often tablets or sometimes a combination of tablets and insulin injections.

Secondary Diabetes Mellitus:

Secondary diabetes occurs when the pancreas is damaged and unable to make insulin. Sometimes it is referred to as Type 3 Diabetes Mellitus.

Secondary diabetes is most commonly caused by pancreatitis or inflammation of the pancreas. Examples of common causes of secondary diabetes mellitus include:

  • Pancreatitis
  • Haemochromatosis
  • Cystic fibrosis
  • Trauma to the pancreas
  • Pancreas surgery such as pancreatectomy
  • Pancreatic agenesis
  • Pancreatic cancer

Gestational Diabetes Mellitus:

Gestational diabetes is diabetes that first appears during pregnancy.

Approximately 12-14% of pregnant women will develop the condition around the 24th to 28th week of pregnancy.

It is important to remember that sometimes women who have no risk factors may develop Gestational diabetes. Therefore, all women should be tested for the condition between the 26th to 28th week of pregnancy or earlier if you have multiple risk factors for the condition. 

Gestational diabetes needs to be monitored closely by the health care team as poorly controlled blood glucose levels can have severe impacts on both the health of the mother and baby.

Gestational diabetes is often managed simply with changes to diet and exercise, however some women may require tablets, insulin injections or both.

Once women with gestational diabetes give birth, the diabetes should go away. However, women who have had gestational diabetes are at greater risk for developing Type 2 Diabetes Mellitus in the future and require lifelong screening.

Risk Factors for Developing Type 1 Diabetes

  • Anyone can get Type 1 diabetes – it does not discriminate. People who have a family history of diabetes eg. a parent or sibling with type 1 diabetes or genetic predisposition are at increased risk of type 1 diabetes. 
  • Sometime triggers like infections can make people more at risk to autoimmune conditions like Type 1 Diabetes Mellitus

Risk Factors for Developing Type 2 Diabetes

There are many factors which may put a person at increased risk of developing this condition. Some of these include:

  • Family history of diabetes
  • Being overweight or obese
  • Being over 45 years old
  • Genetics, especially people from some cultural backgrounds (Aboriginal and Torres Strait Islander, Pacific Islander, Indian and Chinese)
  • Women who have previously had Gestational diabetes while pregnant.
  • Unhealthy diet
  • Sedentary lifestyle
  • Having high blood pressure
  • Having abnormal cholesterol levels in blood

Risk Factors for Developing Secondary Diabetes

  • Pancreatitis
  • Pancreas surgery or removal of the pancreas
  • Medical conditions that can be associated with damage to the pancreas such as cystic fibrosis

Risk Factors for Developing Gestational Diabetes

Only pregnant women can develop gestational diabetes. The risk factors include:

  • Being over the age of 40
  • Having a mother or sister with a history of Type 2 or Gestational diabetes
  • Being overweight or rapidly gaining excessive weight in the first trimester of pregnancy
  • Cultural background (Aboriginal or Torres Strait Islander, Melanesian, Polynesian, Chinese, Southeast Asian, Middle Eastern or Indian)
  • History of Polycystic Ovarian Syndrome
  • Gestational diabetes in previous pregnancies
  • History of large birth weight (greater than 4.5kg) in previous pregnancies.

How Often Should I See My Doctor to Assess My Risk of Diabetes?

Everyone over the age of 40 should be screened for diabetes every three years using a risk calculator like AUSDRISK.

Aboriginal and Torres Strait Islander people should begin having AUSDRISK assessments from the age of 18.

You can calculate your risk using the AUSDRISK score and answering 10 simple questions – https://www.diabetesaustralia.com.au/risk-calculator

Did you know?

Half a million Australians could have Type 2 Diabetes Mellitus but don’t know it!

What are the Symptoms of Diabetes?

The main symptoms of Type 2 Diabetes Mellitus are:

  • Increased thirst and drinking
  • Hunger
  • Frequent urination
  • Tiredness
  • Increased infections
  • Blurry vision
  • Dark pigmentation in certain parts of the body
  • Some people may have no symptoms at all and not know they have diabetes

The main symptoms of Type 1 Diabetes Mellitus are the 4 T’s:

  • Thirst (feeling thirsty and needing to drink more fluids)
  • Toilet (needing to urinate more frequently)
  • Thinner (weight loss)
  • Tired

As insulin production declines, a patient may develop:

  • Stomach pain
  • Vomiting
  • Become very ill

Whatever the type of diabetes if there is sustained, uncontrolled high blood sugar (hyperglycaemia) it can damage the heart, blood vessels, eyes, kidneys and nerves. If you are at risk, see your doctor early to prevent this damage from happening.

Diabetes complications start before diagnosis

  •  If you have risk factors for diabetes do not delay seeing your doctor
  •  As many as half of all people diagnosed with diabetes already have developed one or more diabetes related complications