An Overview of Prediabetes

Prediabetes, a condition that is also described as impaired glucose tolerance or impaired fasting glucose, is considered a precursor of type 2 diabetes. Prediabetes does not typically cause symptoms, but without intervention, it progresses to type 2 diabetes.

This condition is diagnosed with blood tests that measure blood sugar and metabolic parameters. There are well-established strategies for treating prediabetes and preventing the development of type 2 diabetes. Dietary management, weight loss, and exercise are often effective—but sometimes medication is needed.

Symptoms

Prediabetes generally affects adults between the ages of 40 and 60. The condition tends to be silent, rarely causing any noticeable symptoms. In fact, according to the U.S. Centers for Disease Control and Prevention (CDC) , approximately 84 million adults (more than 1 in 3) in the United States have prediabetes, and 90 percent of them don't even know it.

Because of the lack of symptoms, even after diagnosis, most people do not know exactly when their prediabetes began. The condition can remain stable for years before progressing to diabetes.

In the rare instances when prediabetes does cause symptoms, the effects are usually subtle and can easily be missed or mistaken for other health issues.

Signs of prediabetes include:

  • Excessive hunger or thirst
  • Weight gain
  • Fatigue
  • Polyuria (frequent urination caused in large part by increases in fluid intake to relieve thirst)

Complications

Without treatment, prediabetes progresses to type 2 diabetes, a medical condition that causes a number of health complications, including heart disease, vascular disease, cerebrovascular disease, neuropathy, impaired wound healing, and a predisposition to infections.

Prediabetes is not associated with diabetes type 1, a type of diabetes that usually affects young children. And it is not associated with diabetes inspidis, a condition that affects the kidneys.

Causes

Prediabetes involves insulin, an important hormone involved in glucose (sugar) metabolism. If you have prediabetes, you probably make enough insulin, but the cells of your body are resistant to insulin and its effects. This results in a slightly elevated blood glucose level, as well as decreased energy.

Insulin is a hormone produced by the pancreas. It keeps blood sugar levels within a healthy range by helping the cells of the body store glucose. Eventually, the cells convert glucose into energy.

People who have prediabetes produce insulin, but their bodies can't use this hormone the way it should. As a result, the body may actually continue to make more insulin, exacerbating the situation.

Risk Factors

There are several risk factors associated with prediabetes, but the exact cause of the condition is not known. Lack of exercise and a sedentary lifestyle are common among people who have prediabetes.

Hypertension, high cholesterol levels, obesity, and excess body fat, particularly in the abdominal area, are associated with prediabetes. It is not clear whether these health problems cause prediabetes, whether they are caused by prediabetes, or whether they are all caused by another factor.

Associated Conditions

Several metabolic conditions can occur before prediabetes. Insulin resistance is a condition that begins before prediabetes and might not cause high blood sugar. A similar condition described as metabolic syndrome consists of an elevated body mass index (BMI), hypertension, high cholesterol, and insulin resistance.

Diagnosis

Because prediabetes doesn't typically cause symptoms, it is usually detected with screening tests. According to the National Institute of Diabetes and Digestive and Kidney Diseases , people with certain risk factors should be screened for prediabetes.

Screening is recommended if you have any of the following conditions:

  • Age over 45: If your results are normal, testing should be repeated at least at a minimum of three-year intervals, with consideration of more frequent testing depending on initial results (those with prediabetes should be tested yearly)
  • High BMI: If you have a BMI of more than 25 kg/m2 or a waist circumference of more than 40 inches in men or 35 inches in women. The BMI cut-off for Asian Americans is lower (23kg/m2).
  • Belong to a high-risk population: Populations with a higher risk of prediabetes include African Americans, Hispanic/Latinos, American Indians, Alaska Natives, Asian Americans, Pacific Islanders
  • Family history: This includes having a parent or sibling with diabetes
  • Gestational diabetes: A history of gestational diabetes or have given birth to a baby weighing more 9 pounds
  • Lifestyle: Typically physically inactive
  • Hypertension: This is defined as a blood pressure that's equal or greater than 140/90 mmHg or taking therapy for hypertension
  • High fat and cholesterol levels: If you have low levels of high-density lipoprotein (HDL) cholesterol or high levels of triglycerides
  • Predisposing conditions: These include acanthosis nigricans, non-alcoholic steatohepatitis, polycystic ovary syndrome, and atherosclerotic cardiovascular disease
  • Medications: Atypical antipsychotics or glucocorticoids

Screening Tests

There are several blood tests that can be used in prediabetes screening. Often, with prediabetes, the blood glucose is mildly elevated, so your results might not be very abnormal. For this reason, you may need to have more than one blood test.

Common blood tests used in prediabetes screening include:

  • Fasting blood sugar test: This test measures your blood sugar after you have gone without food for eight hours. Normal fasting glucose is below 100 mg/dl, the range of 100 to 126 mg/dl suggests prediabetes, and a level above 126 mg/dl suggests diabetes.
  • Glucose tolerance test: This test measures your blood glucose level before and after you drink a carbohydrate drink. A normal glucose level after drinking a 75 gm glucose load is less than 140 mg/dl, it is between 140 to 199 mg/dl for prediabetes, and it is 200 mg/dl or more for diabetes.
  • A1C test: The results of this test reflect your average blood sugar levels for the previous two to three months. It works by looking at how much your glucose glycates (sticks) to hemoglobin A, a protein found in red blood cells. Once glucose sticks to a hemoglobin protein, it remains there for the lifespan of the hemoglobin A protein, which can be as long as 120 days. The A1C test measures what percentage of hemoglobin A proteins are glycated. For example, a 7 percent A1C means that 7 percent of hemoglobin A proteins are glycated

Prediabetes is diagnosed when an A1C test is in the range of 5.7 % to 6.4 %. Anything under 5.7 % is regarded as normal and above 6.5 % is considered diabetes.

Glucose Monitoring

While it is not required for prediabetes, some people choose to regularly monitor glucose at home. This can help you keep track of how well your treatment plan is working. There are many easy to use glucose monitors, including options that continuously monitor glucose levels.

Treatment

The treatment of prediabetes is focused on taking measures to prevent progression of the condition. Because the mainstay of treatment is lifestyle modification, it can be challenging to maintain consistency.

Regular medical appointments and glucose monitoring can help keep you on track.

Treatment for prediabetes includes:

Weight loss: Even modest weight loss—5 percent to 7 percent of body weight—can prevent or delay the progression toward diabetes. For example, someone who weighs 200 pounds, can lower their risk of developing diabetes by losing just 10 pounds.

Reduction of carbohydrate intake: Carbohydrates are the nutrient that impacts blood sugar the most. The most important carbohydrates to avoid are those that are refined, such as white bread, pasta, rice, and snack foods. It also is helpful to eliminate juice and other sweetened beverages and to increase your intake of non-starchy vegetables.

Following a Mediterranean diet: This means focusing on fruits, vegetables, and healthy fats, such as nuts, seeds, and olive oil.

Medication: If lifestyle changes are not having an effect, then your doctor might recommend medication, such as Glucophage (metformin) to help manage your blood sugar. This medication has been shown to help prevent the development of type 2 diabetes .

Increase in physical activity: Exercise not only helps keep weight in check, but it also helps the body better utilize insulin. Being more physically active can actually help cut your risk for diabetes by half.

​A Word From Verywell

If you have any risk factors for diabetes, it is important that you get appropriate screening done. When your tests show signs of prediabetes, following medical advice can help you avoid diabetes and its associated complications.

Losing weight, exercising, following a nutrient-rich diet and cutting back on sugar and unhealthy fats will help to keep illness and conditions other than diabetes at bay.

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Article Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial policy to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Centers for Disease Control and Prevention (CDC): Prediabetes- Your Chance to Prevent Type 2 Diabetes

  3. National Institute of Diabetes and Digestive and Kidney Diseases, Risk Factors for Diabetes: Prediabetes Screening, How and Why

  4. Moin T.Should Adults with Prediabetes Be Prescribed Metformin to Prevent Diabetes Mellitus? Yes: High-Quality Evidence Supports Metformin Use in Persons at High Risk.Am Fam Physician. 2019 Aug 1;100(3):134-135.

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