At some stage you’ve probably wondered how you developed diabetes and if your children may develop it. In the 1930s scientists made an interesting discovery; they found that some patients were insensitive to insulin treatment. This led them to create a distinction between type 1 and type 2 diabetes. While the two types of diabetes are quite different in how they develop, they do have one factor that is important to both – and that is the susceptibility of inheriting the condition. However, there is usually something in the environment that triggers diabetes to develop.

Type 1 diabetes is an auto-immune condition that affects 10-15% of all people living with diabetes in Australia. All other types of diabetes, including type 2 and gestational diabetes, make up the remaining 85-90% of cases in Australia.  

Type 1 diabetes 

Type 1 diabetes is said to be an autoimmune disorder which results in the destruction of insulin-producing pancreatic beta-cells requiring lifelong insulin therapy treat the condition. The interaction between genes and the environment is thought to stimulate the immune response that destroys the cells. Type 1 diabetes cannot be prevented. Genes alone are not enough to cause type 1 diabetes and environmental triggers such as temperature and viruses play a role. Type 1 diabetes develops more often in winter than summer, and it’s possible that a virus that has only mild effects on most people triggers type 1 diabetes in others.   

Type 2 diabetes  

Type 2 diabetes, the most common type of this complex condition and is said to account for 85% of cases (some studies put the figure closer to 90%) and generally happens at an older age of life. Numerous studies have identified genetic and non-genetic factors associated with this type of diabetes. Our genes also play an important role in type 2 diabetes. Just as in type 1 diabetes, some genetic risk factors can be passed down through families, and having more of those high-risk genetic factors will increase the likelihood of you developing the condition. 

There are also a number of non-genetic factors that are associated with type 2 diabetes. Behaviours including alcohol intake, smoking and sedentary lifestyles have been known to be associated with type 2 diabetes. There is a stronger family history link for developing type 2 diabetes compared to type 1 diabetes. But because families tend to have similar lifestyles, it can be difficult to determine if type 2 diabetes is caused primarily by lifestyle or genetics. Unlike type 1 diabetes, you can reduce your risk of type 2 by maintaining a healthy weight. 

Monogenic diabetes 

Maturity Onset of Diabetes of the Young (MODY) is a monogenic form of diabetes and differs from type 1 and type 2 diabetes. In the United States, monogenic forms of diabetes account for about 1 to 4% of all cases of diabetes. A change in a single gene is what causes this rare form of diabetes, and it can be passed down from parent to child. A child of someone with MODY has around a 50% (or 1 in 2) chance of developing the condition. MODY is managed with insulin injections so it is important that people with monogenic diabetes get the right diagnosis. 

Gestational diabetes

Gestational diabetes (GDM) is a form of diabetes that occurs during pregnancy. The main contributor to elevated blood glucose levels for women with gestational diabetes is the insulin resistance that occurs due to pregnancy hormones. This can be thought of as a reduction in the action of the mother’s insulin due to the effects of pregnancy hormones. With a reduced effectiveness of insulin, blood glucose levels rise. Women who have a family history of type 2 diabetes, or a first degree relative (mother or sister) who has had gestational diabetes, are at an increased risk of developing gestational diabetes when pregnant.

By Robbie Tyson CDE APD