Is diabetes hereditary?
If you have a parent or sibling with diabetes, you’re more likely to develop the disease because there’s a relationship between certain genes and the development of diabetes. But your likelihood of inheriting diabetes depends in part on the type of diabetes in your family’s health history.
The good news is that having genetic risk factors for any type of diabetes does not necessarily mean you’ll develop it. There are many other contributing factors such as diet, lifestyle and environment.
Here’s what you need to know:
How a family history of diabetes affects your risk
Researchers have identified dozens of genes that may predispose you to developing diabetes Type 1 or 2. But according to the American Diabetes Association (ADA), those genes are often just part of the equation. Two factors play an important role in developing any type of diabetes:
- Inheriting a predisposition to the disease from a family with a history of diabetes
- An environmental trigger, such as diet, lifestyle, illness or even weather
Without an environmental trigger, diabetes remains inactive. The ADA presents identical twins as an example. They are often exposed to different environmental triggers while having the same predisposition to diabetes. When one twin has Type 1 diabetes, the other gets the disease about half the time. If one twin has Type 2 diabetes, the other will develop it about 75% of the time.
To complicate the link between genetics and diabetes further, the type of diabetes in your family may determine your predisposed risk:
Type 1 diabetes
Type 1 diabetes is an autoimmune disorder that causes abnormally high blood sugar. The body’s immune system attacks the cells in the pancreas that make insulin, which regulates your blood sugar levels.
The genetic connection for Type 1 diabetes is not always clear-cut – an estimated 85% of people diagnosed with type 1 diabetes do not have a family history of the disease. But as an autoimmune disease, Type 1 diabetes is linked to specific genes. According to the ADA, if one or both parents have Type 1 diabetes, a child’s risk of the disease is higher:
- If only the man has Type 1 diabetes, his children’s chances of getting the disease are 1 in 17.
- If only the woman has Type 1 diabetes, her children’s risk for the disease is between 1% and 4%, depending on the mother’s age when she gave birth.
- If both parents have Type 1 diabetes, the risk of children developing it is between 10% and 25%.
If someone is predisposed to Type 1 diabetes, the disease can occur at any age and depends on exposure to triggers which may include:
- Certain viral infections, which may trigger the immune system to attack insulin-making cells
- Cold weather, with one theory being that spending more time indoors spreads viral infections more easily
- Early diet, with studies showing a link between being breastfed in infancy and a lower risk of type 1 diabetes
Type 2 diabetes
Type 2 diabetes accounts for 90% to 95% of all diabetes cases. It tends to occur at age 45 or later, though it can develop at any age. The body doesn’t make insulin properly (called insulin resistance), resulting in abnormally high blood sugar levels.
Compared to Type 1 diabetes, Type 2 has a stronger link to family history – having a first-degree relative with the condition makes you three times more likely to develop it. If one parent has Type 2 diabetes, your lifetime risk is 40%. The risk increases to 70% if both parents have it.
The risk of Type 2 diabetes is also highly dependent on lifestyle choices, which are often influenced by family. Obesity, poor diet and a lack of exercise all make you more likely to develop the disease. The good news is that positive lifestyle changes can help prevent the onset of Type 2 diabetes.
Gestational diabetes causes abnormally high blood sugar levels only during pregnancy. Women who have gestational diabetes typically have normal blood sugar levels before and after pregnancy.
Experts believe that developing gestational diabetes depends on a combination of genes, environmental triggers and lifestyle factors. While there’s not a clear line of inheritance, many people with gestational diabetes have at least one parent or sibling with gestational or Type 2 diabetes.
Women with gestational diabetes also need to be aware of their increased future risk for developing Type 2 diabetes. About half of women with gestational diabetes go on to develop Type 2 diabetes.
If you’re genetically predisposed to diabetes…
If any type of diabetes runs in your family, be sure to share that information with your primary care provider. Knowing your family history allows your doctor to make informed care decisions and guide you in lifestyle choices.
If you have a family history of Type 1 diabetes, your provider may recommend an antibody test, which can diagnose the disease or determine your risk for it.
If you have a family history of diabetes, reach out to your primary care provider, who can guide you in prevention strategies and lifestyle choices.