What Causes Diabetes?

More than 34 million Americans have diabetes, and as many as 95% of Americans with diabetes have type 2 diabetes. They didn’t develop diabetes overnight; it takes years for type 2 diabetes to develop, and many lifestyle choices factor into the risk for developing the disease.

There is no cure for diabetes, which means that prevention is key.

Understanding what causes diabetes and what you can do to lower your risk for type 2 diabetes can help you protect yourself and your family from the disease.

There are several lifestyle changes that you can make to lower your risk for type 2 diabetes. Click To Tweet

What causes type 2 diabetes?

It’s difficult to pinpoint the exact cause of type 2 diabetes. However, there are things that increase a person’s risk for developing the disease.

Risk factors you can’t change

People with a family history of diabetes are at an increased risk for developing the disease.

A personal history of prediabetes increases your risk for type 2 diabetes.

The older you are, the higher your risk for type 2 diabetes. The disease is most often diagnosed in people over the age of 45. 

Men are more likely than women to have undiagnosed diabetes.

Certain ethnic/racial groups are at an increased risk for type 2 diabetes:

  • African Americans
  • Alaska Natives
  • Native Americans
  • Asian Americans
  • Hispanics/Latinos
  • Native Hawaiians
  • Pacific Islanders

Lifestyle risk factors

People who are overweight or obese are at an increased risk for diabetes. Being overweight or obese can affect insulin resistance, a condition in which fat cells, muscles, and the liver do not use insulin well. Insulin resistance is a common trait in people with type 2 diabetes.

The location of body fat can also affect risk; excess belly fat is associated with insulin resistance and type 2 diabetes.

Sedentary living is a major risk factor for type 2 diabetes. Regular exercise helps you maintain a healthy weight, but physical activity also improves blood glucose control.

Low HDL cholesterol levels, high triglyceride levels, or both, are associated with increased risk.

High blood pressure increases your risk for type 2 diabetes.

People who smoke are 30 to 40% more likely to develop type 2 diabetes than people who do not smoke. Smokers are more likely to be physically inactive, and they are more likely to have cardiovascular problems — such as high blood pressure — than nonsmokers.

What are the signs and symptoms of diabetes?

Type 2 diabetes is most commonly diagnosed in people over the age of 45. However, an increasing number of children and young adults are being diagnosed with type 2 diabetes.

Learn to identify common warning signs and symptoms of diabetes:

  • increased thirst
  • frequent urination
  • fatigue
  • weight loss
  • numbness in the extremities
  • blurred vision

These symptoms typically develop gradually over time, but they can also develop quickly.

Type 2 diabetes symptoms may be so mild that are not noticeable. Some people with type 2 diabetes don’t experience symptoms at all, and it’s possible to have diabetes or prediabetes without knowing it. One-third of Americans have prediabetes, and 90% of them don’t know that they have it.

An absence of symptoms does not make the disease harmless, however. High blood glucose levels can cause irreversible damage to your body over time, regardless of whether or not you have symptoms in the early stages of the disease.

Ways you can help prevent diabetes

Manage a healthy weight

Staying at a healthy weight helps lower your risk for type 2 diabetes. Eat a nutritious diet, and consume proper portion sizes. Regular physical activity also helps you maintain a healthy weight.

Watch what you eat

Reduce the amount of sugar that you consume, especially added sugars. While sugar has not been shown to directly cause diabetes, consuming excess sugar can lead to weight gain which does increase your risk for type 2 diabetes.

It’s not just about removing unhealthy foods, though. Add whole grains, vegetables, and fiber to your diet.


You need physical activity every single day. Regular exercise provides numerous health benefits and has been shown to lower your risk for type 2 diabetes.

Avoid smoking

Smoking is the leading cause of preventable death, and it has been linked with insulin resistance and an increased risk for type 2 diabetes.

Know your risk

Knowing your risk can help you make necessary changes to prevent type 2 diabetes. You can get started with this risk quiz from the American Diabetes Association. However, you should never rely on online tools to determine your health needs — share your results with your doctor.

Screening for type 2 diabetes

The U.S. Preventive Services Task Force recommends that adults between the ages 40 and 70 screen for diabetes; get a screening every three years if your test results are normal.

Talk to your doctor

Your primary care physician is your main point of contact for all of your health needs. Whether you are concerned about your symptoms or you just want to learn more about your risk for diabetes, your doctor can help.