Diabetes 101: What are the different types?

One of the biggest health challenges in Australia, diabetes is often misunderstood.

Here, we look at the different types of the condition, including type 1, type 2 and gestational diabetes, plus pre-diabetes, and how each can impact your health.

About 1 in 20 Australians (almost 1.3 million people) live with diabetes. Those figures don’t include gestational diabetes, which effects almost 18% of pregnant women in Australia.¹

Diabetes is a chronic condition that affects the way your body turns food into energy. When you have diabetes, there’s too much glucose (a form of sugar) in your blood. This is because the hormone insulin, which helps process that glucose into energy, is either not being produced or is not working as well as it should. This causes the glucose to build up, rather than enter your body’s cells.

High blood glucose levels (BGLs) can cause unpleasant symptoms and, over time, harm your organs. This can damage your blood vessels and nerves, leading to complications including kidney, heart, foot and eye damage.²

There are 3 main types of diabetes:

• type 1 diabetes
• type 2 diabetes
• gestational diabetes.

Around 2 million Australians further live with pre-diabetes, a condition that puts you at a heightened risk for developing type 2 diabetes.³

If you live with type 1 diabetes, the cells in your pancreas that produce insulin are destroyed by your immune system.

Usually diagnosed in childhood, type 1 diabetes is not the result of lifestyle factors (like poor diet). Its cause isn’t completely understood, however there is a strong genetic link. It may also be triggered by viruses or other autoimmune diseases.

Symptoms of type 1 diabetes can come on suddenly and may include:

• excessive thirst
• frequent urination
• weight loss
• hunger
• irritability
• fatigue
• blurry vision.⁴

More than 130,000 Australians live with type 1 diabetes.⁵

About 90% of diabetes cases in Australia are type 2, which typically affects people over 40 (although more and more younger people are being diagnosed).⁶

Type 2 diabetes develops when you become resistant to the insulin your body produces and, gradually, lose your ability to produce enough of it.

When you’re insulin resistant, the cells in your liver, fat and muscles don’t respond well to insulin, so your pancreas pumps out more insulin to keep your BGLs within a normal range.

Initially, there are no symptoms of insulin resistance, as your BGLs are within a normal range. But, over time, your pancreas can’t keep up with this increased production and your BGLs rise.

Symptoms of type 2 diabetes can be very mild and even go unnoticed for years. However, some warning signs to watch out for include:

• excessive thirst
• frequent urination
• fatigue
• hunger
• slow-healing cuts.⁷

You're more likely to develop type 2 diabetes if you:

• have a family history of type 2 diabetes
• are overweight or obese, particularly around the waist
• don't exercise often
• smoke
• drink alcohol excessively
• are of Aboriginal or Torres Strait Islander background
• are of Pacific Islanders, Māori, Asian, Middle Eastern, North African or Southern European background
• are over 55
• have high blood pressure or cholesterol
• have a history of heart attack or stroke
• have polycystic ovary syndrome (PCOS) and are overweight
• are taking certain types of medications (like antipsychotic or steroid medications)
• have had gestational diabetes
• have pre-diabetes.⁶

Unlike type 1 diabetes, type 2 diabetes can often be prevented (or better managed) by addressing certain modifiable lifestyle factors, such as quitting smoking, maintaining a healthy weight, eating a healthy diet and exercising regularly.

Gestational diabetes occurs when someone who doesn’t have diabetes experiences high BGLs during pregnancy.

As a foetus grows, the mother’s body needs to produce more insulin. If the mother is unable to do this, BGLs rise, causing gestational diabetes.

Most people don’t experience symptoms when they have gestational diabetes. However, symptoms can include:

• increased thirst
• excessive urination
• fatigue
• thrush.⁸

Gestational diabetes is usually picked up during a routine pregnancy oral glucose tolerance test (OGTT), which is done at around 24 weeks gestation.

BGLs need to be carefully monitored during pregnancy and after birth to avoid complications.

While gestational diabetes usually disappears after giving birth, it can reappear during future pregnancies. The condition also increases the mother and baby’s risk of developing type 2 diabetes.⁸

Pre-diabetes is a warning sign that you’re on track to developing type 2 diabetes. It occurs when BGLs are too high, but not high enough to be diagnosed as diabetes.  

Like type 2 diabetes, there are often no symptoms for pre-diabetes. So, it’s common for people to live with the condition for years without detecting it.

That said, you’re more likely to have pre-diabetes if you meet any of the risk factors for type 2 diabetes (listed above).⁹

The good news is that pre-diabetes is reversable with certain lifestyle changes. The best defence against developing it is to eat a healthy, balanced diet, exercise regularly and maintain a healthy weight.

Diabetes Australia offers resources on preventing and living with diabetes. Visit their website or call them on 1800 177 055.

The National Diabetes Service Scheme (NDSS) offers online resources, advice and a dedicated helpline on 1800 637 700.