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6 Things You Need to Know About Prediabetes

The more you know — beyond how it's ‘not quite’ diabetes — the better you can protect yourself

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While more than 1 in 3 adults have prediabetes, very few know it. That means the red-flag condition can’t send its important message that diabetes may be right around the corner (and that you may already be at risk for some serious health issues). 

What, exactly, is prediabetes? It's when your blood sugar levels are higher than they should be, but not yet high enough to be considered diabetes. 

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Here are six things you need to know about the condition that affects roughly 96 million U.S. adults, including how to recognize it in time to turn things around. 

1. Its cause is the same as diabetes

The same factors that raise your risk for type 2 diabetes can set you up for a diagnosis of prediabetes. 

With the condition, cells in your body aren’t responding normally to insulin, a hormone made by your pancreas that acts like a key to let blood sugar into cells to use as energy. Your pancreas responds by making more insulin, but eventually, as cells continue to not respond, it can’t keep up. At that point, your blood sugar rises, setting the stage for prediabetes — and, by extension, diabetes.

2. Diabetes isn’t inevitable

Not all people with prediabetes go on to develop type 2 diabetes, but almost all people with the type 2, the most common form of diabetes, start out with prediabetes. 

For some people with the condition, early treatment, as well as moderate lifestyle changes, can actually return blood sugar levels to a normal range, effectively preventing or delaying diabetes. Prediabetes itself is often reversible (more on that below). 

How can I find out if I have prediabetes?

To see if you’re at risk for prediabetes, take this test (available in English and Spanish) from the American Diabetes Association (ADA). The only way to know for sure is to ask your health care provider to run a blood test. 

3. Prediabetes can be a hazard for your heart

The “pre” may lead you to believe the condition isn’t serious, but prediabetes puts you at a higher risk for not only diabetes, but also heart disease and stroke. 

Experts have known about the link between diabetes and cardiovascular disease for a while now, including that cardiovascular disease is the most common cause of death among people with diabetes. But more recent research shows that people with prediabetes are also at substantial risk of developing cardiovascular disease. 

That risk is especially pronounced in the first five years of prediabetes. If you do nothing about prediabetes, your risk of developing cardiovascular disease — which includes high blood pressure, heart disease, stroke, and other disorders of the heart and blood vessels — is about 50 percent. 

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4. Symptoms are often absent

Some people with prediabetes experience increased thirst, frequent urination, fatigue and blurred vision — which are also signs of diabetes. But more often than not, there are no clear symptoms. That’s why it’s important to talk to your doctor about having your blood glucose tested if you have any of the following risk factors:

  • You’re 45 or older.
  • You're overweight. 
  • You have a parent, brother or sister with type 2 diabetes. 
  • You lead a sedentary life. 
  • You've had diabetes during pregnancy (gestational diabetes) or given birth to a baby that weighed more than 9 pounds. 

5. It’s diagnosed with a blood test

The only way to know for sure if you have prediabetes is to ask your health care provider to run one of the following three types of blood tests. If you’re diagnosed with prediabetes, you should be checked for type 2 diabetes every one to two years. 

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A1C Test

This simple blood test measures your average blood sugar for the past two to three months. The advantages of being diagnosed this way are that you don’t have to fast or drink large amounts of anything. Note: Your doctor may report your A1C results as eAG, or “estimated average glucose,” which directly relates to your A1C.

Normal: < 5.7 percent<117 mg/dl
Prediabetes: 5.7-6.4 percent117-138 mg/dl
Diabetes:≥ 6.5 percent≥139 mg/dl

Fasting Plasma Glucose (FPG) Test

This test checks your fasting blood sugar levels. Since it requires fasting— taking in nothing but water for at least eight hours before the test — it’s usually done first thing in the morning.

Normal:  <100 mg/dl 
Prediabetes:  100–125 mg/dl 
Diabetes: ≥126 mg/dl 

Oral Glucose Tolerance Test (OGTT)

This two- to three-hour test measures your body’s response to sugar. Your doctor will check your blood sugar levels before you drink a special sweet drink and again two hours later.

Normal:  <140 mg/dl
Prediabetes:  140-199 mg/dl
Diabetes: ≥200 mg/dl

6. Prediabetes is reversible

In the early stages of prediabetes (and diabetes, for that matter), paying attention to diet and exercise can improve blood sugar numbers, essentially “reversing” the disease and reducing the odds of developing diabetes. 

The American Diabetes Association (ADA) recommends 150 minutes of moderate-intensity aerobic activity, as well as two to three strength training sessions, per week. Not only will that sort of commitment to exercise help keep your weight in check, it will also improve blood glucose levels.

And while there is no “prediabetes diet” (or, for that matter, a “diabetes diet”), the ADA recommends a number of eating plans, including Mediterranean, low-carb, vegetarian, and others that emphasize nonstarchy vegetables; whole, minimally processed foods; and little added sugar.

A few other things that may help you mitigate your risks: 

  • Maintain a healthy weight. If you’re overweight, even a little weight loss can help. A landmark study at the National Institutes of Health (NIH) found that lifestyle changes leading to a weight loss of 7 percent in overweight participants with prediabetes reduced their risk of diabetes by 58 percent. Participants over age 60 reduced their chances of developing diabetes by 71 percent, compared with those who didn’t lose weight. 
  • Talk to your doctor about whether it makes sense for you to take the drug metformin. Considered the first-line treatment to help control blood sugar for people with type 2 diabetes, the drug is also recommended by the ADA for people with prediabetes and certain other risk factors. The NIH study found that overweight participants with prediabetes who took metformin lowered their chances of developing diabetes by 31 percent, compared with those who didn’t take the drug or undergo lifestyle changes. The Food and Drug Administration hasn’t approved metformin — or any other medication —for prediabetes, so it is prescribed “off-label.” 

If you have underlying risk factors that put you at greater risk for diabetes — say, for instance, you’re over age 45 or diabetes runs in your family — you’ll need to continue to pay attention to blood sugar levels and lifestyle choices. Otherwise, your prediabetes will return.

Find support for prediabetes

A support group can help you make the necessary lifestyle changes to avoid progressing to diabetes. Not sure how to find one? 

The ADA organizes workshops geared to a variety of different groups. To find one near you, contact the ADA (800-DIABETES).

The Centers for Disease Control and Prevention (CDC) National Diabetes Prevention Program can also help you learn about healthy lifestyle changes — related to eating habits, exercise and more — shown to reverse prediabetes. The program is offered at YMCAs, community centers, churches and hospitals across the country. To find one near you, enter your zip code into the CDC’s program finder tool.  

Similarly, Medicare offers a Diabetes Prevention Program, which is covered for many Medicare enrollees. 

Editor's note: This article was originally published on November 2, 2018. It was updated on Sept. 7, 2023.

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