Diabetes 101: Causes, symptoms and treatment

Diabetes is a chronic condition that affects how your body regulates blood sugar, or glucose. It affects about 12% of the U.S. population, including 11 million adults who don’t know they have it, according to the Centers for Disease Control and Prevention (CDC).

If you don’t treat it, diabetes can lead to major health issues over time, like heart disease, nerve damage, kidney disease and eye damage/retinopathy. Diabetes also puts you at a higher risk of developing several cancers, including liver cancer, pancreatic cancer and endometrial cancer.  

That’s why recognizing the signs of diabetes and getting diagnosed early is so important. The sooner you know you have diabetes, the sooner you can take steps to manage it and protect your long-term health.

Here’s what I tell patients I see in UT MD Anderson’s Diabetes Clinic.

What are the different types of diabetes

The two main types of diabetes are Type 1 and Type 2.

Type 1 diabetes

Type 1 diabetes occurs when your pancreas produces little or no insulin.

What causes Type 1 diabetes?

Type 1 diabetes is considered an autoimmune disease. Your body’s immune system makes antibodies that destroy the insulin-producing cells in your pancreas.

Type 1 diabetes is somewhat rare. It is most often diagnosed in children, teens and adults under age 30. But older adults can also be diagnosed with Type 1 diabetes.

Some cancer patients may develop diabetes as a side effect of cancer treatment. This is called secondary diabetes. About 1% of our patients treated with immune checkpoint inhibitors at UT MD Anderson develop treatment-related Type 1 diabetes.

Type 2 diabetes

Type 2 diabetes develops when your pancreas produces insulin but your body’s cells do not respond to it. This is called insulin resistance.

What causes Type 2 diabetes?

Type 2 diabetes is the most common type of diabetes. You can develop it at any age. Obesity and lack of physical activity can increase your risk.

Gestational diabetes

Gestational diabetes is a type of diabetes that develops during pregnancy. It’s caused by the hormonal changes that happen in a woman’s body during pregnancy. The body becomes more resistant to insulin, causing blood sugar levels to rise.

Blood sugar levels usually return to normal after a woman gives birth.

Prediabetes

Prediabetes is when your blood sugar levels are higher than normal, but they don’t quite reach the threshold for diabetes. Having prediabetes increases your risk of developing Type 2 diabetes.

What are the early warning signs of diabetes?

Diabetes symptoms can be subtle and nonspecific, especially in the early stages. That’s why it’s important to pay attention to changes in your body and how you feel.

Common diabetes symptoms include:

• Frequent urination
• Excessive thirst
• Fatigue
• Unexplained weight loss
• Increased hunger
• Blurry vision
• Frequent infections
• Slow-healing wounds

See a doctor if you have any of these symptoms. They can evaluate you and determine if you should be tested for diabetes.

When is diabetes a medical emergency?

Type 1 and Type 2 diabetes often share similar symptoms. However, as Type 1 diabetes progresses, sometimes it can lead to a life-threatening condition called diabetic ketoacidosis (sometimes referred to as DKA).

This happens when your liver breaks down fat instead of glucose (sugar) for energy to fuel your body. This produces acidic chemicals called ketones. When these ketones are produced too quickly, it can result in dangerous levels in your body. Though people with Type 2 diabetes can also develop DKA, it’s more common in people with Type 1 diabetes.

Symptoms of diabetic ketoacidosis may include:

• Abdominal pain
• Nausea and vomiting
• Extreme fatigue
• Malaise, or general unwell feeling

Diabetic ketoacidosis is considered a medical emergency. Seek medical care right away if you have any of these symptoms. For some people, a trip to the emergency room for DKA is how they first learn they have Type 1 diabetes.

How is diabetes diagnosed?

Doctors use blood tests to diagnose diabetes. These tests can also be used to diagnose prediabetes.

A1C test

Your A1C is an average of your blood sugar levels over three months. You have diabetes if your A1C is equal to or higher than 6.5%.

Fasting blood sugar test

If you have a fasting blood sugar equal to or higher than 126mg/dL on two separate tests, you have diabetes. Fasting means you did not eat or drink anything other than water before the test.

Random blood sugar test

If you have two random tests where your blood sugar is equal to or higher than 200mg/dL, you have diabetes. The tests do not have to be taken while you’re fasting.

Oral glucose tolerance test

This test is used less often. Your blood sugar is tested once while fasting and again two hours after drinking a sugary liquid. A high blood sugar on the second test may indicate diabetes.

How is diabetes treated?

Treatment depends on the type of diabetes you have.

Type 1 diabetes treatment

Because the pancreas no longer produces enough insulin, people with Type 1 diabetes need insulin replacement. Insulin can be delivered through injections or an insulin pump.

Type 2 diabetes treatment

People with Type 2 diabetes still produce insulin, but their bodies don’t use it effectively. Treatment options can include:

• Oral medications
• Non-insulin injectable medications
• Insulin
• Lifestyle changes, including diet and exercise

How can lifestyle changes help with diabetes?

Maintaining a healthy weight, staying physically active and eating a balanced diet can help improve blood sugar levels and reduce insulin resistance. If you have prediabetes, these behaviors can also help lower your risk for developing Type 2 diabetes.

Aim for a balanced diet that includes lots of fruits and vegetables and some carbohydrates, healthy fats and lean protein.

Eat complex carbohydrates, such as:

• Whole grains
• Lentils
• Beans and legumes

Try to limit:

• White bread
• Potatoes
• Refined pasta

Avoid added sugars, such as:

• Soda
• Candy
• Pastries

Managing diabetes during cancer treatment

If you have diabetes, it’s very important to manage your blood sugar while undergoing cancer treatment. Certain therapies used during cancer treatment, like chemotherapy, immunotherapy and steroids can raise your blood sugar. This can make common cancer treatment side effects, such as dehydration, harder to manage.

At UT MD Anderson, our endocrinologists help patients manage diabetes throughout their cancer treatment. This includes testing for secondary diabetes, starting them on insulin when needed, providing education and helping them safely monitor their blood sugar.

Cancer treatment affects more than just the cancer itself. That’s why at UT MD Anderson, we use a multidisciplinary approach to support every aspect of your health, including diabetes management and treatment-related side effects.

Nupur Kikani, M.D., is an endocrinologist at UT MD Anderson who also sees patients in our Diabetes Clinic.

Request an appointment at UT MD Anderson online or call 1-877-632-6789.