Is Type 2 Diabetes Genetic?

More than37 million Americans have diabetes.¹ Of those, around 95% have type 2 diabetes. The condition is becoming more common alongsidethe number of overweight and obese people worldwide.² Despite this, there are multiple reasons why people develop type 2 diabetes. Research has linked the condition to irreversible and reversible risk factors.

But what is your risk? If you have the genetic markers for type 2 diabetes, are you guaranteed to develop the disease? It's important to understand the role of genetics in type 2 diabetes and how diet and lifestyle can play a significant part. In this article, you'll learn more about what type 2 diabetes is, how your genetics affect your risk, and when you should see a doctor. 

What is type 2 diabetes?

Type 2 diabetes is the most common form of diabetes. It accounts for about 95% of all diabetes cases, and it's becoming more common. Type 2 diabetes compromises your body's ability to regulate your blood glucose (sugar) levels.

Your body needs sugar to create glucose for energy. Sugar comes from the food you eat, most often carbohydrates, like bread, pasta, or potatoes. After you eat, your body breaks the carbohydrates down into glucose. It releases glucose into the bloodstream, which you can measure through your blood glucose levels.

This is when a hormone called insulin gets to work. Your pancreas secretes insulin and sends it into the bloodstream. Insulin moves glucose from the bloodstream and into your cells for energy. That's why blood glucose levels naturally rise and fall during the day. They are typically lower before a meal and higher after you've eaten. However, there is an optimal range for blood glucose levels, usually between 68 mg/dL (3.8 mmol/L) and 140 mg/dL (7.8 mmol/L).

When you have type 2 diabetes, your body resists insulin (known as “insulin resistance”) and doesn't produce enough of the hormone to overcome it. This means that higher levels of glucose can build up in your bloodstream. Over time, elevated blood glucose levels can lead to severe health conditions.

Fortunately, type 2 diabetes is a manageable condition. Most people can improve their type 2 diabetes through dietary changes and other lifestyle adjustments, such as increasing their daily exercise. In some cases, a doctor may also recommend oral medications with or without insulin therapy to bring blood glucose levels back into a healthy range.  

Most healthcare providers now take what’s known as a person-centered approach³ to helping people care for their diabetes. This approach encourages shared decision-making to address your needs and preferences when choosing diabetes treatment strategies. 

It's essential to diagnose and treat type 2 diabetes as early as possible to prevent the many associated complications. If left untreated, elevated blood glucose levels can result in: 

• Vision loss and other eye diseases

• Certain types of dementia

• Kidney damage

• Heart disease

• Increased risk of heart attack and stroke

• Foot infections and risk of amputation

• Nerve damage causing loss of feeling and pain

• Sexual dysfunction

If you experience any signs of type 2 diabetes, make an appointment with your primary care physician. The symptoms of type 2 diabetes are similar to other diabetes types and include: 

• Needing to urinate more frequently

• Feeling thirstier than normal 

• Unexplained weight loss, often accompanied by increased appetite

• Blurry vision

• Tingling or numbness in your limbs

• Slow-healing sores

• Frequent infections

How is diabetes diagnosed and treated?

Your doctor can run blood tests to determine if you have type 2 diabetes. Some of these tests may require you to fast, so ask your doctor if you can eat or drink beforehand. The tests will measure your blood glucose levels at specific times of the day, which will tell your doctor more about how your body is handling glucose and responding to insulin. They may need to do a series of tests to determine if you have type 2 diabetes.

If your doctor diagnoses you with type 2 diabetes, they'll help you develop a treatment plan. That might include changes to your diet, such as following a low-carb meal plan. It might also include changes to your lifestyle, such as increasing the amount of exercise you get each day. You may also need to take medication in the form of oral tablets with or without insulin therapy.

Some people with type 2 diabetes will need to carefully monitor blood glucose levels at home. You can perform finger prick testing with a blood glucose meter or wear a continuous glucose monitoring device (CGM). 

These methods allow you to check your blood glucose levels and track them over time. Based on the readings, you can determine if you need to make changes to keep your blood sugar within the healthy range set by your doctor. Your diabetes healthcare team will also be able to review your blood glucose levels over time to determine if you need to make changes to your treatment plan.

We have so many effective treatment strategies, so it's possible to live a long and healthy life with type 2 diabetes.

Is type 2 diabetes genetic?

Your genetics play a substantial role in the development of type 2 diabetes. There’s a stronger link⁴ between family history and type 2 diabetes than there is between family history and type 1 diabetes.

Researchers have identified well over 500genetic markers for type 2 diabetes.⁵ Having more of these increases your risk of developing the condition. You inherit these genes from your parents, so your risk for type 2 diabetes increases if other close family members also have the condition. 

• If one parent had type 2 diabetes, you have a 40% chance⁶ of developing the condition. 

• If both parents had type 2 diabetes, you have a 70% risk⁶ of developing the condition. 

There are also inherited genetic markers⁷ that may contribute to obesity by increasing hunger and food intake. These gene variants can also increase the risk of developing type 2 diabetes.

However, it's not just the genes you inherited from your parents that can put you at risk. Lifestyles you have learned from them can put you at risk, too. If you weren’t encouraged to cook, relied on prepackaged food, and led a sedentary lifestyle, you may continue that into adulthood. 

If your parents taught you to eat a nutrient-dense, well-balanced diet, this could lower your risk of developing type 2 diabetes. If you grew up in an active family that made exercise a part of your daily routine, this might also lower your risk if you carry those habits into adulthood. 

Importantly, while your genetic makeup can increase your risk of developing type 2 diabetes, carrying these genetic markers doesn’t guarantee that you’ll develop the condition. They might make you more susceptible to developing the condition but environmental and lifestyle factors may have a bigger impact. It’s the combination of environmental, lifestyle, genetic, and other inherited factors that determines your risk.

Fortunately, it's possible to reduce the chances that you'll develop type 2 diabetes. You can make changes to your diet, lifestyle, and environment. You and your healthcare providers can create an action plan to delay or even prevent the development of the condition.

What are the genetic risk factors for type 2 diabetes?

Researchers are eager to pinpoint which genetic markers indicate an increased risk of developing type 2 diabetes. If they can determine the genes responsible, genetic testing could identify those most at risk. They could help these people delay or avoid the development of type 2 diabetes.

While researchers⁸ have identified hundreds of genes associated with type 2 diabetes, the specific role of many of these genes and their impact on your risk isn't certain. Some genetic markers play a more significant role than others. 

Is there genetic testing available for type 2 diabetes?

Genetic testing could tell you whether you have some of the genetic markers for type 2 diabetes. However, because research into the role of genetics in type 2 diabetes is ongoing, these tests aren't the best risk indicators. 

Knowing your family's health history is a better predictor of risk. If a close family member has diabetes, such as a parent or sibling, you have a much greater chance of developing it.

What are other causes of type 2 diabetes?

While genetics play a role, other factors can lead to the development of type 2 diabetes. You can develop type 2 diabetes even if there is no history of the disease in your family. This is why it's important to report any type 2 diabetes symptoms to your doctor so they can determine if you need further testing. 

Some of the other causes of type 2 diabetes include:

Being overweight

Carrying excess fat can lead to insulin resistance. Insulin resistance means your body isn't using insulin effectively, leaving too much glucose in your bloodstream. Some people with insulin resistance overcome this when their body produces more insulin. If your body cannot produce enough insulin to overcome that resistance, it can result in type 2 diabetes.

Excess weight can also cause chronic inflammation in the body. Chronic inflammation has links to the development of type 2 diabetes and many other serious medical conditions. 

Researchers have also found that carrying a lot of excess weight around your midsection is a better predictor of inflammation than BMI. If your excess weight is primarily in your midsection, it could increase your risk of developing type 2 diabetes versus someone who carries extra weight in other areas.

Having a high BMI 

High BMI is one of the primary risk factors for type 2 diabetes. Because there are other risk factors involved, you can develop the condition even if you have a healthy BMI. This is sometimes called lean diabetes. If you are experiencing any of the symptoms of type 2 diabetes, talk to your doctor, even if you aren't overweight.

Leading a sedentary lifestyle

Many people lead sedentary lifestyles due to desk jobs and spending many hours in front of the television. Researchers found that sitting for long periods each day can increase your risk⁹ of developing type 2 diabetes by slowing down your body's metabolic response. 

A slower metabolic response can lead to insulin resistance. 

Even increasing light activity can improve your body's ability to process glucose and get it out of your bloodstream. It's best to get at least 30 minutes of moderate exercise a day.

Developing insulin resistance

Being overweight or sedentary can lead to insulin resistance, but they aren't the only things that can cause this condition. Certain medications, hormonal disorders, and some sleep disorders can also cause insulin resistance. 

If you become pregnant, you may develop gestational diabetes due to increased insulin resistance and insufficient insulin supply. After a diagnosis of gestational diabetes, you’re 60% more likely to develop type 2 diabetes later in life. 

Being over the age of 45

Those who are middle-aged are more at risk of developing the condition, and that risk increases as you grow older. The American Diabetes Association recommends routine screening starting at 45,¹⁰ with testing every three years.

Is it possible to prevent type 2 diabetes?

If you know you are at risk of developing type 2 diabetes, it's possible to reduce that risk. With the proper intervention, you can delay or prevent the onset of the disease. You can do this by: 

Maintaining a healthy body weight

If you are already at a healthy weight, work to stay there. Your risk of type 2 diabetes goes up with your BMI. If you are overweight, losing just 5% of your body weight can reduce your risk by 58%. 

Eating a well-balanced, nutrient-packed diet

Carbohydrates increase your blood sugar levels, so sticking to low-carb diets rich in lean protein, healthy fats, and whole grains can keep your blood glucose levels in a healthy range. If you aren't sure where to start, ask your doctor for a referral to a dietician. They can help you build meal plans focusing on the prevention of diabetes. 

Getting more exercise

Exercise is a very effective way of regulating your blood sugar without medicine because your body will use the glucose in your bloodstream for energy. Exercise increases your insulin sensitivity, making insulin more effective. Aim for at least 30 minutes of exercise a day. 

You need to make a lifelong commitment to these changes to prevent type 2 diabetes. 

When should I see a doctor?

Make an appointment with your primary care physician or another healthcare provider if you are experiencing any of the symptoms of type 2 diabetes. They can run blood tests to determine how your body processes glucose and uses insulin. 

The lowdown

Type 2 diabetes accounts for 95% of all diabetes cases and is becoming increasingly common. Type 2 diabetes can develop from irreversible risk factors like genetics and ethnicity, as well as reversible factors like diet, physical activity, and smoking.

Genetics plays a significant role in the development of type 2 diabetes. Researchers have identified many possible genetic markers associated with an increased risk of the condition. Carrying these markers doesn't guarantee you'll develop type 2 diabetes, but having multiple markers increases your risk. While genetic testing for these markers is available, knowing your family's health history is more reliable in predicting your risk. 

Fortunately, it's possible to take steps to reduce the chance that you'll develop type 2 diabetes by making changes to your lifestyle and environment. You can work closely with your doctor and health care team to create an action plan for delaying or preventing type 2 diabetes.