In type 2 diabetes, your body may still make insulin, but is unable to effectively use the insulin it does make (insulin resistance). Eventually the body doesn’t make enough insulin (insulin deficiency). Type 2 used to be called “non-insulin dependent diabetes.” People who have it can be treated with proper meal planning, physical activity, and may require medications. Type 2 diabetes is the most common form of diabetes and accounts for 90%-95% of cases. Although it can occur in younger people, people over 45 years of age are at higher risk.
Some people are more prone to diabetes.
- The tendency to develop type 2 diabetes is inherited (present at birth).
- It does not always come from being too heavy.
- It is not caused by eating too much sugar.
Causes of type 2 diabetes
No one knows the exact cause of type 2 diabetes. We do know that it is more likely to occur in people who have certain risk factors, such as older age, obesity, family history of type 2 diabetes, and certain race/ethnicity (African American, Hispanic/Latino American, American Indian, Asian American, or Pacific Islander).
Symptoms and Diagnosis of Type 2 Diabetes
In its early stages, type 2 diabetes often has no symptoms. When symptoms do occur, they may come on gradually and be very subtle. They may include:
- increased hunger and thirst
- numbness or tingling in hands or feet
- blurred vision
- frequent gum, skin, or bladder infections
- slow healing of cuts or sores
- feeling tired
- frequent infections
- increased urination
In the U.S., type 2 diabetes is frequently not diagnosed until many years after it begins, when complications appear. Approximately one-fourth of all people with diabetes may be undiagnosed. The American Diabetes Association recommends that people age 45 and above be tested for diabetes at least every 3 years. Adults who are overweight or obese and who have one or more additional risk factors for diabetes should also be tested at least every 3 years, regardless of age.
The preferred test for diagnosing type 2 diabetes is the fasting plasma glucose (FPG) test.1 This blood test requires fasting (no food or drink except water) for at least 8 hours and is usually done in the morning.
Other tests for diabetes are the casual plasma glucose test (a blood test taken at any time of day without regard to time since last meal), the oral glucose tolerance test (OGTT: a blood test taken at 2 hours after drinking glucose dissolved in water), and the glycated hemoglobin (A1C).
A diagnosis of diabetes is made if a person has any of the following test results1:
- FPG is 126 mg/dL or higher.
- High blood sugar (hyperglycemia) symptoms exist and casual plasma glucose is 200 mg/dL or higher.
- Plasma glucose is 200 mg/dL or higher at 2 hours during an OGTT.
- A1C is greater than or equal to 6.5%.
If any of these test results occur, testing should be repeated on a different day to confirm the diagnosis.
What is pre-diabetes?
Before people develop type 2 diabetes, they almost always have “pre-diabetes”—blood sugar (glucose) levels that are higher than normal but not yet high enough to be diagnosed as diabetes. As of 2010, there were at least 79 million people in the United States aged 20 years or older with pre-diabetes.2 A diagnosis of pre-diabetes is made using the FPG test, the OGTT, or the A1C. Depending on which test is used, pre-diabetes is categorized as2:
- Impaired fasting glucose (IFG): FPG is 100 mg/dL to 125 mg/dL.
- Impaired glucose tolerance (IGT): plasma glucose is 140 mg/dL to 199 mg/dL at 2 hours during an OGTT.
- A1C: 5.7% to 6.4%.
Recent research has shown that some long-term damage to the body, especially the heart and circulatory system, may already be occurring during pre-diabetes. Research has also shown that if you take action to manage your blood sugar when you have pre-diabetes, you may be able to delay the onset of type 2 diabetes. Much of the same advice for good nutrition and physical activity that is given to patients who have diabetes can benefit people with pre-diabetes. See our Nutrition and Exercise section of this website to begin learning about the positive steps you can take.
Treatment of Type 2 Diabetes
Although diabetes cannot be cured, it can be managed by various treatments including the use of diabetes medications. These include several types of oral and injectable medications and the various types of insulin. While most people with type 2 diabetes take either diabetes pills, insulin or both, a few can manage their blood sugar with careful meal planning and regular physical activity
Common treatment stages for type 2 diabetes:
Diabetes is different for each person. Depending on the stage of your diabetes and your body’s response to certain therapies, your doctor may prescribe one or more treatments. For example, you may be able to manage your diabetes with diet and exercise alone, or with the addition of a single diabetes pill or more than one diabetes pill. Some people may use pills plus an injectable product like insulin or a glucagon-like peptide-1 (GLP-1) receptor agonist. For others, it may make more sense to start with insulin injections instead of pills. It’s common for your therapy to change from time to time, depending on the stage of your diabetes. Your blood sugar readings will help you and your doctor identify whether there is a need to change your treatment plan.
Meal planning and exercise are important parts of diabetes management, regardless of the type of medicine used. Always talk with your healthcare provider before beginning an exercise program or making significant changes to your diet.
The steps below are common ways to treat type 2 diabetes. You and your doctor will determine the best therapy for you.
Many people with type 2 diabetes are able to take diabetes pills to manage their blood sugar. These pills are not insulin. Oral medications work in different ways to lower blood sugar. Some pills help your body use the insulin it makes, and some pills help your body make more insulin. In order for diabetes pills to work, your body must be able to make insulin. This is why diabetes pills cannot be used to treat type 1 diabetes.
The chart below shows the type of medications and how they work. Check with your healthcare provider to find out how your diabetes pills work.
Glucagon-like peptide-1 (GLP-1) receptor agonists (injectable) A GLP-1 receptor agonist is a unique kind of drug for the treatment of type 2 diabetes. It “mimics” many of the actions of a naturally occurring hormone from the intestines and can help the body make more of its own insulin. The most common side effects include nausea and vomiting. Low blood sugar (hypoglycemia) can occur when used with a sulfonylurea. Pancreatitis, which can be life threatening, and, allergic reactions, which may be serious, can occur.
Insulin (injectable) There are several types of insulin products available to replace the insulin the body can’t make. Most people use more than one type of insulin to more closely mimic the way the body’s own insulin would act. Low blood sugar is a possible side effect of all insulins.