The CGM Blog
Does Diabetes Run in the Family?
If one of your parents or close relatives is living with diabetes, you may be wondering whether you’re more likely to develop diabetes too. Neither type 1 diabetes (T1D) nor type 2 diabetes (T2D) has a specific cause. They are complex conditions that are affected by many factors, from genetics and preexisting health challenges to environmental influences like diet, lifestyle, and stress.
Everyone living with diabetes has a unique mix of factors that may have led to the development of the condition and no two people’s experience of it is exactly the same.1 Having a close relative who is living with diabetes does not mean that you or someone else in your family will be diagnosed as well.2 However, knowing that your genetics might increase the likelihood of developing diabetes empowers you to take steps to prevent or support yourself through a diabetes diagnosis.
The Role Genetics Play in Diabetes
T1D and T2D are very different conditions, and the reasons that someone might develop one are not the same as the other. Genetics have been found to be a factor in both T1D and T2D, but research has shown that even if someone has a genetic predisposition to the disease, something in the environment usually triggers its development.2
Genetics and Type 1 Diabetes
T1D happens because of an autoimmune event that destroys the cells in the pancreas that produce insulin. Insulin is the hormone—or chemical messenger—that allows sugar molecules from the foods we eat, known as glucose, to be used by our bodies for energy.3 Children are more likely to be diagnosed with T1D, but adults over 30 can develop what’s known as latent autoimmune diabetes in adults (LADA).4
When a person is likely to develop T1D, there are specific antibodies present that indicate that there might be an attack on the cells in the pancreas.5 Antibodies are the cells in the body that help fight off infections and viruses, but under certain circumstances, they can harm other cells in the body itself, which is called an autoimmune event.6 Researchers have found that everyone who has T1D has a set of genes in common, even if they don’t have any relatives with T1D.7 The genes called HLA-DR3 or HLA-DR4 are linked to autoimmune diseases like T1D.2 These genes may impact whether a person has the antibodies that are likely to attack insulin-producing cells.5
Even though we know that there is a genetic component to the development of T1D, why and how some individuals have the genes associated with T1D but don’t develop the condition isn’t entirely clear. Even identical twins do not always share a T1D diagnosis.2 Research has shown that there are some characteristics that make it more likely that a person has T1D in their genes. For example, the genetic factors that contribute to the development of T1D are more common in white individuals who have Northern European ancestry.5
If you are a parent living with T1D, your child may be at increased risk for developing the condition as well but the causation is far from straightforward. A variety of factors like how old you were when you developed diabetes, whether you’re the father or mother, and at what age you give birth all have an impact on a child’s risk level.2 If both parents have T1D, their children’s risk of developing T1D is between 10%–25%.2
Genetics and Type 2 Diabetes
T2D occurs over time as insulin production in the pancreas slows down and cannot make enough insulin to meet the body’s needs. It can also happen when the cells in the body become less receptive to the signals that insulin is sending, which is known as insulin resistance.8
T2D is closely linked to family history and ancestry. Individuals who have a parent or sibling who lives with diabetes are more likely to develop the condition. In addition to your family history, your ethnic background also has an influence. Individuals who are of African, Arab, Asian, Hispanic, Indigenous, or South Asian descent have an increased risk of living with type 2 diabetes.9
Several genes are thought to influence T2D, including many gene combinations that are common amongst both people who do and do not live with the condition. This makes it difficult to know for sure exactly which genes are partly responsible for T2D.10
Understanding the Complex Causes of Diabetes
There are many layers to a diabetes diagnosis. Environmental factors also make a significant impact on the likelihood that a person develops T1D or T2D. Everyone’s health is impacted by things that happen to us throughout our lives, from the eating habits taught to us by our parents to stressful circumstances like losing a loved one. While genes are important to consider, doctors take into account many other facets of a person’s lifestyle and overall health when assessing their risk for diabetes.
Here are some of the other factors that may contribute to the development of T1D:2,11
- Having a severe viral infection
- Experiencing cold temperatures
- Whether a child is breastfed as an infant
- Having celiac disease
- Experiencing gut microbiome disruption from antibiotics
- Not getting enough vitamin D
A few of the environmental factors that can point to increased risk of developing T2D can include:9
- Having high blood pressure
- Having high cholesterol
- Having a high BMI or are overweight, especially if you have a larger stomach
- Having Polycystic Ovary Syndrome (PCOS)
- Dealing with a psychiatric disorder like schizophrenia, depression, or bipolar disorder
- Experiencing sleep apnea
You’re also more likely to develop T2D if you have associated genetic and ethnic factors and are over 40 years old. In light of this, Diabetes Canada recommends that those 40 and over get tested for diabetes every three years.8
What to Do if You’re At Risk
If you know that diabetes is common in your family, it’s important to stay in conversation with your doctor about your risk. Make sure that you are tested regularly if it’s recommended for you to do so. Be aware that not everyone shows symptoms, especially if they are living with T2D.12 The symptoms of T1D typically develop very quickly and need to be addressed immediately if you experience them.13
Maintaining a healthy lifestyle that incorporates movement you enjoy, nutritious meals, and techniques for managing and reducing stress can all have a positive impact on your risk of developing T2D.14 Generally, taking these steps can help you have a great quality of life even if you are diagnosed with T1D or T2D.15
T2D and Prediabetes
Prediabetes is a condition where blood sugar levels are higher than normal, but not quite high enough to be considered T2D. The condition can lead to T2D if it’s not addressed and properly treated.16 Prediabetes is reversible if you are able to lower your blood sugar levels. If you’ve received a prediabetes diagnosis, it’s critical to prioritize your health which likely requires a few lifestyle changes. These might include a new nutrition and exercise plan as well as weight management strategies. Your doctor will be able to guide you through the process of determining the steps you need to take to support your health.16
Moving Forward When You Receive a Diabetes Diagnosis
A diabetes diagnosis is never an individual’s fault. It’s important to understand that popular ideas of what causes diabetes, such as eating too much sugar or experiencing obesity, aren’t always accurate.1 If you’ve been diagnosed with diabetes, don’t blame yourself. The complex factors that led to developing diabetes are largely out of your control, which can feel overwhelming, confusing, and even scary. Luckily, there are plenty of tools and resources to help you regain a sense of control through effective diabetes management.
When you’re taking the first steps on your diabetes journey, it’s a great idea to educate yourself about what diabetes is. Alongside the guidance and advice from your doctor and diabetes care team, exploring self-care strategies empower you to feel your best while keeping you on track with your diabetes management goals. Finding a supportive community of other people going through the same things you are can boost your mental health and remind you that you’re never alone when it comes to living with diabetes. You can check out stories from our Dexcom Warrior community and sign up to join the thriving global group of individuals courageously tackling the challenges of living with diabetes with confidence.
Get educational information about managing your diabetes, including topics like preparing to travel, diabetes and exercise, supporting children living with T1D, and navigating popular diabetes diets, on The CGM Blog.