Blood sugar levels that are higher than normal, but not high enough to be called diabetes, are classified as prediabetes. Prediabetes is also called impaired glucose tolerance or impaired fasting glucose. Evidence indicates that people with prediabetes can take steps to return their blood sugar levels to a normal range. This can prevent or delay complications that are linked to diabetes.
How Serious Is the Problem?
Other long-term health problems can result if you do not have good control over your blood sugar levels. Complications related to type 2 diabetes include but are not limited to:
- Kidney disease
- Nerve damage
- Limb amputation
- Cognitive decline
- Increased risk of infection
- Joint problems
What Are the Risk Factors?
Being overweight is the major risk factor for prediabetes and diabetes. Obesity and type 2 diabetes make your body cells less sensitive to the effects of insulin, a hormone that regulates blood sugar levels. This allows blood sugar levels to rise over time and can result in long-term damage to your body.
This is an especially important risk factor for Americans since many are overweight. African Americans, Hispanics, Native Americans, Asian Americans, and Pacific Islanders may be at an even higher risk, probably due to genetics.
How Do You Detect Prediabetes?
Prediabetes and diabetes can be diagnosed with a simple blood test. During a routine office visit, your doctor can order tests, such as:
- Fasting plasma glucose test
—You will fast for at least 8 hours and have your blood glucose measured before eating. Your results may be read as follows:
- Normal: 60-99 milligrams per deciliter (mg/dL)
- Prediabetes: 100-125 mg/dL
- Diabetes: 126 mg/dL or above
Oral glucose tolerance test
—You will fast for at least 8 hours and have your blood glucose measured after the fast. Then you will drink a sugary drink and have your blood glucose measured 2 hours later. Results 2 hours after the drink are usually as follows:
- Normal: below 140 mg/dL
- Prediabetes: 140-199 mg/dL
- Diabetes: 200 mg/dL or above
- Hemoglobin A1c (HbA1c)
— A blood test that does not require any fasting. The HbA1c is an indicator of your average blood sugar levels over the previous 2 to 3 months. Your results may be read as follows:
- Normal: below 5.7%
- Prediabetes: 5.7%-6.4%
- Diabetes: 6.5% or above
Who Should Get Screened?
The American Diabetes Association (ADA) recommends that the following people get screened for diabetes:
- Adults of any age who are overweight or obese with 1 or more of these risk factors:
- First-degree relative with diabetes
- Low HDL (good) cholesterol level and high triglycerides levels
- High blood pressure
- History of diabetes during pregnancy (gestational diabetes) or having a baby weighing over 9 pounds
- Having polycystic ovary syndrome or other conditions associated with insulin resistance
- Being inactive
- History of cardiovascular disease
- Belonging to an at-risk ethnic group (African American, Hispanic, Native American, Hispanic American, Asian American, or Pacific Islander)
- Previous blood test results that show HbA1C levels at 5.7% or higher, impaired glucose tolerance, and impaired fasting glucose
- Adults aged 45 or older without any risk factors
- Overweight children over 10 years old (or after puberty starts) with 1 or more of these risk factors:
- High body mass index (BMI) based on child's weight and height
- Family history of any type of diabetes, including during pregnancy
- Signs of insulin resistance or having a condition associated with insulin resistance
- At-risk ethnic background
How Do You Treat Prediabetes?
If your test indicates prediabetes, you should have it repeated for accuracy. If you do have prediabetes, you will need to be retested every year.
Fortunately, we know that people with prediabetes can delay or prevent the onset of diabetes with lifestyle changes. Experts recommend that people with prediabetes reduce their weight by 5-7% and engage in modest physical activity for at least 150 minutes each week. In addition to exercising, you doctor will also recommend that you make changes to your diet. This may include eating more fruits and vegetables and whole grain foods. You should also limit your intake of sugar-sweetened drinks.
If you already drink alcohol, limit your drinking to moderate to amounts of alcohol. This is 2 drinks per day for men, 1 drink per day for women. Some studies have shown a benefit for people who drink moderately.
In some cases, medications commonly used to treat diabetes may be prescribed to prevent people from developing diabetes.
American Diabetes Association
National Diabetes Education Program
Public Health Agency of Canada
Canadian Diabetes Association
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Last reviewed July 2016 by Michael Woods, MD Last Updated: 8/2/2019