What is Prediabetes?

diabetes screening on calendar
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Definition: Prediabetes is part of the Type 2 diabetes spectrum of disorders thought to be primarily caused by insulin resistance and/or damage to the insulin-producing cells (beta-cells) in the pancreas.  It is diagnosed in the same way diabetes is diagnosed, but the cut-offs on the tests are different.  Any one of three tests can be interpreted as prediabetes:

1) Hemoglobin A1C (also often just called A1C) - This blood test can be done any time, and is an average of the blood glucose in the last two-three months, although it is weighted towards more recent blood glucose.

  Less than 5.7% on this test is normal, 5.7% to 6.4% is prediabetes, and higher this is diabetes.

2) Fasting Blood Glucose Test -   This test is a blood test usually done first thing in the morning before eating.  If the results are between 100 and 125 mg/dL (5.6-6.9 mmol/L), this is called Impaired Fasting Glucose, and the person is considered to be prediabetic.  Over this would be diabetic.

3) Glucose Tolerance Test - In the most common version of this test, the person is given a drink of glucose, and then the blood is checked two hours later.  If the blood glucose is between140-199 mg/dL [7.8-11 mmol/L]), this is considered Impaired Glucose Tolerance, and the person would be considered to prediabetic.  200 or over on this test would be considered to be diabetes.


4) Metabolic Syndrome - It has been suggested by some physician groups (e.g. the American Association of Clinical Endocrinologists) that even without abnormal fasting glucose or glucose tolerance tests, if a person meets the criteria for metabolic syndrome they should be considered prediabetic, but this is not currently an accepted standard.

How Common is Prediabetes?

Somewhere around 38-40% of adults in the United States have prediabetes.  Between prediabetes and diabetes, the latest report says the diabetes spectrum now affects more than half of us.

Risks of Prediabetes

The main risk of prediabetes is that the person is very likely to become diabetic within a few years.

  Also, people with prediabetes have most of the risk factors of diabetes, but at lower levels.  Even if they do not go on to get diabetes, people with prediabetes are more likely to have or to get heart disease, nerve damage, and kidney damage than people with normal blood glucose.

How to Prevent Prediabetes from Becoming Diabetes

Generally, the recommendations for prediabetics are to become more active (for example, brisk walking for 30 minutes 5 days per week, and sitting less) and to lose a modest amount of weight (10-15 pounds makes a big difference) by reducing calories in the diet.  That's generally pretty much it.  But I would add the following:

1) Get a Blood Glucose Monitor - Become familiar with your blood glucose and what affects it.  What foods send your blood glucose into the abnormal range?  The effects of exercise and weight loss have a longer-term effect, but it can be very motivating to see changes in your blood glucose.  I have been a prediabetic for over 10 years, and monitoring my blood glucose has been key in keeping it from progressing.  Why I Check My Blood Glucose

Also, if your blood pressure is high, monitor it in the same way.  The same things that bring your blood glucose under control can have a positive effect on your blood pressure.

2) Consider a Lower-Carb Diet - There is some evidence that a lower-carb diet can help prevent the progression of prediabetes to diabetes, and it doesn't necessarily have to be super-low in carbs.  Eliminating most added sugars and refined carbohydrates can do the trick for many people, and that will often make people less hungry, so they automatically consume fewer calories.