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What Is Prediabetes? Here's What You Need to Know

If you've been told you have diabetes, there are steps you can take to prevent prediabetes from becoming type 2 diabetes.

What Is Prediabetes?

You can think of prediabetes as an early warning sign that you might be headed toward diabetes. The telltale sign is a blood test that show your blood sugar (blood glucose) level is higher than normal but not yet high enough to be considered diabetes.

Why might this matter? Prediabetes is an indication that you could develop type 2 diabetes (T2D) if you don’t make some immediate and lasting lifestyle changes.

The Good News Is—You Can Take Steps to Reduce Your Risks

it is very possible to prevent prediabetes from developing into type 2 diabetes. The most obvious is taking a look at your food choices. By eating whole (minimally or unprocessed) foods (ie, whole wheat vs blanched white flour-based products, white rice, potato chips—which are a far cry from a baked potato), addressing overweight and staying at a healthy weight, and committing to some physical activity—which can be a walk or two daily—is enough to help get your blood glucose level back into the normal range. That's the key to assuring you avoid not only the onset of diabetes but all the related complications including heart disease, vision, loss, nerve damage, and kidney failure.
How much do you know about this condition and what it might mean for you? Take this Quiz: How Much Do You Know About Prediabetes

What Are the Symptoms that Suggest You May Be Heading Toward Diabetes?

Diabetes develops very gradually, so when you’re in the prediabetes stage—when your blood glucose level is higher than it should be—you may not have any symptoms at all. You may, however, notice that:
  • you’re hungrier than normal
  • you’re losing weight, despite eating more
  • you’re thirstier than normal
  • you have to go to the bathroom more frequently
  • you’re more tired than usual
All of those are typical symptoms associated with diabetes, so if you’re in the early stages of diabetes, you may notice them.

Recognizing Prediabetes: Common Causes and Risk Factors  

Prediabetes develops when your body begins to have trouble using the hormone insulin. Insulin is necessary to transport glucose—what your body uses for energy—into the cells via the bloodstream. In pre-diabetes, your body either doesn’t make enough insulin or it doesn’t use it well (that’s called insulin resistance).
If you don’t have enough insulin or if you’re insulin resistant, you can build up too much glucose in your blood, leading to a higher-than-normal blood glucose level and perhaps prediabetes.
Researchers aren’t sure what exactly causes the insulin process to go awry in some people. There are several risk factors, though, that make it more likely that you’ll develop pre-diabetes. These are the same risk factors related to the development of type 2 diabetes:
  • Weight: If you’re overweight (have a body mass index—a BMI—of higher than 25), you’re at high risk for developing prediabetes, especially if you carry a lot of extra weight in your abdomen, you may develop prediabetes. The extra fat cells can cause your body to become more insulin resistant.
  • Lack of physical activity: This often goes hand-in-hand with being overweight. If you aren’t physically active, you’re more likely to develop prediabetes.
  • Family history: Prediabetes has a hereditary factor. If someone in your close family has (or had) it, you are more likely to develop it.
  • Race/ethnicity: Certain ethnic groups are more likely to develop prediabetes, including African-Americans, Hispanic Americans, Native Americans, and Asian Americans.
  • Age: The older you are, the more at risk you are for developing prediabetes. At age 45, your risk starts to rise, and after age 65, your risk increases exponentially.
  • Gestational diabetes: If you developed diabetes while you were pregnant, that increases your risk for developing prediabetes later on.

Other health problems: High blood pressure (hypertension) and high cholesterol (the “bad” LDL cholesterol) increase your risk of getting type 2 diabetes. 

Polycystic ovary syndrome (PCOS) also raises the risk of prediabetes because it’s related to insulin resistance. In PCOS, many cysts form in your ovaries, and one possible cause is insulin resistance. If you have PCOS, that means you may be insulin resistant and therefore at risk for developing prediabetes.

If you have hypothyroidism (low thyroid function; not enough circulating thyroid hormone), and you have prediabetes, then your risk of developing T2D more than doubles in comparison to individuals with normal thyroid function.

How Is Prediabetes Diagnosed?

Your doctor may want to test your blood glucose levels if you’re overweight (have a body mass index—BMI—of over 25) and if you have one or more of the risk factors listed above.
Even if you aren’t overweight and don’t have any of the risk factors, your doctor may want to start testing your blood glucose level every three years beginning when you’re 45. That’s a smart thing to do because the risk of developing prediabetes (and therefore type 2 diabetes) increases with age. Because there are so many possible complications of diabetes (e.g., heart problems and nerve problems), it’s a good idea to be vigilant about detecting blood glucose abnormalities early.
To diagnose you with prediabetes, the doctor can run one of two tests—or he or she may decide to do both. The tests are:
  • Fasting plasma glucose test (FPG): You can’t eat anything for eight hours leading up to an FPG test. That's why this test is often done in the morning. The doctor checks your blood glucose level (blood sugar level) after drawing a small blood sample.

    If your blood glucose level is between 100 and 125mg/dL, you have prediabetes. You may hear the doctor use the phrase “impaired fasting glucose” or IFG, which is another term for prediabetes when it’s diagnosed with the fasting plasma glucose test.

    If your blood glucose level is above 126mg/DL with the FPG test, you may have diabetes.
  • Oral glucose tolerance test (OGTT): This is another test used to diagnose prediabetes. The doctor will give you instructions on how to prepare for the test, but you won’t be able to eat anything for eight hours before the test; you’ll be fasting. In that way, the oral glucose tolerance test, abbreviated OGTT, is similar to the fasting plasma glucose test.

    On the day of the test, the doctor will test your blood glucose level at the beginning of the appointment; that’s called your fasting blood glucose level. Then, you’ll drink 75g of a very sugary mixture. Two hours later, your blood glucose level will be measured.

    If your blood glucose level is between 140 and 199mg/dL two hours after drinking the sugary mixture, you have pre-diabetes. You may hear the doctor use the phrase “impaired glucose tolerance” or IGT, which is another term for pre-diabetes when it’s diagnosed with the OGTT.

    If your blood glucose level is above 200mg/DL with the oral glucose tolerance test, you may have diabetes. 

Know the Lifestyle Recommendations for Taking Control of Prediabetes

The American Diabetes Association says that serious lifestyle changes are effective in preventing type 2 diabetes after you’ve been diagnosed with pre-diabetes. Your doctor will walk you through what you need to change, but typical recommendations are:
  • Evaluate Your Food Choices: A registered dietitian (RD) or certified diabetes educator (CDE) can help you create a meal plan respects your preferred foods and also reflects good-for-your-blood-glucose-level foods. The goal of the healthy food plan is to assure that you are controlling your blood glucose level by keeping it in a healthy, normal range. Your meal plan should be adjusted to be comfortable and satisfying to you, taking into account your overall health, physical activity, and what you like to eat. There are no diets out there that will work nearly as well as one that has been worked out with your likes and dislikes, cultural preferences, 
  • Exercise: When you exercise, your body uses more glucose, so exercising can lower your blood glucose level. Also when you exercise, your body doesn’t need as much insulin to transport the glucose; your body becomes less insulin resistant. Since your body isn’t using insulin well when you have prediabetes, lower insulin resistance is a very good thing.

    And of course, there are all the traditional benefits of exercise: it can help you lose weight, keep your heart healthy, make you sleep better, and even improve your mood.

    The American Diabetes Association recommends at least 150 minutes of moderate activity a week—that’s 30 minutes five days a week. You can get that through activities such as walking, bike riding, or swimming.
  • Lose weight: If you’re overweight, you should get started on a weight loss program as soon as you’re diagnosed with prediabetes. Losing just 5 to 10% of your weight can significantly reduce your risk of developing type 2 diabetes. The combination of eating well and exercising more is a great way to lose weight—and then maintain your new, healthy weight.
  • Metformin: For people who are at very high risk of developing type 2 diabetes after being diagnosed with prediabetes, the doctor may recommend medication. The American Diabetes Association says that metformin should be the only medication used to prevent T2D. It works by keeping the liver from making more glucose when you don’t need it, thereby keeping your blood glucose level in a better range.
Your doctor will keep a close watch on your blood glucose levels, monitoring them to make sure that your prediabetes doesn’t progress to type 2 diabetes. If needed, he or she may suggest adjustments (e.g., different diet or more exercise) to better control your blood glucose levels.
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