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Prediabetes and increased risk for diabetes and other health problems

If you have prediabetes, you have blood sugar levels that are elevated (higher than normal), but not high enough to for the diagnosis of diabetes. However, your risk of developing type 2 diabetes is dramatically increased. You are not alone, the US Centers for Disease Control and Prevention (CDC) estimates that 1 in 3 adults over the age of 20 in the US has prediabetes. Approximately 70% of these will develop type 2 diabetes at some point in the future.1

Learning that you have prediabetes can be scary. However, there is a positive side to this discovery. Getting this news means that you have caught a serious health condition in the early stages while it is developing. This gives you time and motivation to make life changes that can prevent progression to type 2 diabetes.

Look at it this way, you have a second chance to take positive steps that can make a powerful difference in protecting you from health problems like heart disease, stroke, kidney disease, vision problems, and other complications that are common with type 2 diabetes. The earlier you take action to manage your elevated blood glucose, the better chance you will have at slowing down or even stopping the progression to type 2 diabetes.

Research has shown that people who have prediabetes who lose weight and get regular physical activity can prevent or delay progression to type 2 diabetes and, in some cases, even get their blood glucose levels to return to the normal range. Additionally, elevated blood glucose and prediabetes are often part of a set of interrelated health problems, including high blood pressure and abnormal lipids (elevated triglycerides, and decreased high-density lipoprotein [HDL] cholesterol). In many people these health problems, along with increased body weight, are present before blood glucose becomes elevated and are part of a larger pattern of health issues that contribute to the development of type 2 diabetes. So, in addition to losing weight and becoming more active, you should work with your doctor to make sure that your blood pressure and lipids are well controlled.

Learn more about controlling blood pressure and lipids.

Diagnosing prediabetes

Your doctor will use blood glucose testing to determine if you have prediabetes. Several different tests are useful in determining whether you have elevated blood glucose. Two terms that are sometimes used to describe prediabetes are impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). IFG is determined using a fasting blood glucose test that measures blood sugar after a fasting period of 8 hours. You usually fast over night and have your blood drawn in the morning. IGT can be tested using a simple random (non-fasting) blood glucose test. Additionally, a oral glucose tolerance test can be used to screen for IGT.

The most widely used test to diagnose prediabetes is the hemoglobin A1C test. This is simple blood test that does not require fasting or eating or drinking anything special. A diagnosis of prediabetes can be made if your A1C falls within the range of 5.7% to 6.4%. Your doctor may also use a fasting blood glucose test to diagnose prediabetes. If your fasting blood glucose level is at or higher than 100 mg/dL and no higher than 125 mg/dL, the test is considered positive for prediabetes.2

Whichever of these tests your doctor uses, an initial positive test must be confirmed by the results from a second positive test in order to make a diagnosis. 2

Diagnosing Prediabetes



Hemoglobin A1C 5.7–6.4%
Fasting blood glucose 100–125 mg/dL
Random blood glucose 140–199 mg/dL
Oral glucose tolerance test† 140 to 199 mg/dL

*Diagnosis requires that results from an initial test must be confirmed with a second test.

†Blood glucose test done 2 hours after a 75-gram glucose drink.

Prediabetes: a growing problem

The latest statistics from the US Health and Human Services indicate that prediabetes is a growing problem in this country. Based on statistics from 2005 to 2008, the CDC found that 35% of US adults (age 20 years and older) had prediabetes, with the highest rate among adults 65 years of age and older. Prediabetes affects 1 in 2 adults (50%) in this age range. When these percentages are applied to the entire population of the US using 2010 census data, this translates to 79 million adults 20 years of age or older with prediabetes.
Research shows that individuals with prediabetes who do not take steps to address their risk are very likely to develop type 2 diabetes diabetes within the next 10 years.1

What are the symptoms of prediabetes?

In most cases, prediabetes develops without any symptoms at all, which is one reason why it is such a dangerous health condition. You may feel fine physically, even while elevated blood glucose and the complex of related health problems (high blood pressure, excess body weight, abnormal lipids) are causing damage in your body. In fact, research has shown that only about 11% of people with prediabetes are diagnosed. Most people discover that they have the condition when they are being screened or examined for some other reason, such as an annual physical or check-up.

Causes of prediabetes

In prediabetes, the body loses the ability to use the insulin it produces effectively (this is called “insulin resistance”) and we experience changes in the balance of hormones responsible for glucose control. We know that being overweight starts the process of events inside the body that leads to the development of insulin resistance. In addition to insulin resistance, loss of the ability to produce insulin also plays a role in elevated blood glucose.

As prediabetes progresses to type 2 diabetes, a person may progressively lose as much as 50% of their ability to make the insulin they need. In addition to a deficiency in insulin, abnormalities and changes with other hormones involved in glucose control occur. The process that leads to prediabets and the eventual development of type 2 diabetes, involving insulin resistance and loss of the ability to produce insulin, can begin 5 to 10 years before a person is diagnosed with type 2 diabetes.3,4

A number of factors contribute to increased risk for prediabetes and development of type 2 diabetes. The most important of these appears to be genetics (a family history of type 2 diabetes). However, several lifestyle factors appear to contribute to risk.5

Genetics. There is a strong genetic component to type 2 diabetes and pre diabetes. In other words, if type 2 diabetes runs in your family, your chances of developing the disease are greater.3

Lifestyle factors. Research has shown that several lifestyle factors, including lack of physical activity, , being overweight or obese, and smoking, may contribute to increased risk of developing prediabetes and type 2 diabetes.

This is good news if you have prediabetes, because, unlike with genes (your stuck with them!), it’s possible to make changes to your lifestyle and reap the health benefits.

Studies have shown that obesity increases your risk for type 2 diabetes and losing weight can decrease your risk. Additionally, regular moderate physical activity—a good way to lose and keep weight off and improve cardiovascular fitness—has been shown to decrease risk for type 2 diabetes.5

Importance of controlling calories

When it comes to what you eat, most research shows that controlling calorie intake (and body weight) is the most important factor in decreasing risk for type 2 diabetes. In terms of specific foods, a pattern of eating that includes large quantities of foods, such as red meat, processed meats, and beverages sweetened with sugar, may increase your risk for developing type 2 diabetes. On the other hand, a diet rich in fruits, vegetables, nuts, whole grains, and olive oil may decrease your risk of developing type 2 diabetes. Therefore, the wisdom is to limit consumption of foods in the first group and increase consumption of foods in the second group.4

Studies have established a link between smoking and risk of developing diabetes (one study even showed that second-hand smoke increased risk). However, the link is not as clear as with obesity and lack of physical activity. Additionally, quitting smoking is sometimes accompanied by weight gain. You should definitely consider kicking the habit, if you smoke, but conventional wisdom says that your smoking cessation plan should include strategies for losing weight and getting regular exercise.5

Learn more about healthy lifestyle change I can make, including weight loss, healthy eating, and physical activity to lowering blood sugar.

Lifestyle changes can make a big difference!

In fact, results from a large US National Institutes of Health (NIH)-funded Diabetes Prevention Program (DPP) study conducted at centers throughout the country over a period of 3 years, including over 3,000 individuals with prediabetes showed the power of lifestyle changes in reducing risk of progression to type 2 diabetes.5

In the study, participants were randomly assigned to different interventions, including an intensive program of lifestyle modification (a healthy diet, regular exercise, and behavior modification) or drug therapy with the diabetes drug metformin and information on diet and physical activity. Both groups reduced their risk of developing type 2 diabetes, but the group that received lifestyle modification had the most dramatic reduction in risk. For participants in this group, a weight reduction of 5% to 7% (this translates to a loss of about 10-14 lbs in a person who weighs 200 lbs) reduced the risk of being diagnosed with type 2 diabetes by almost 60%.5

This demonstrates the huge potential for lifestyle changes in reducing diabetes risk. And those lifestyle changes don’t necessarily have to be extreme. To get their exercise, most participants in the DPP study were not running marathons, but walking regularly (at least 30 minutes a day for 5 days a week).

Written by: Jonathan Simmons | Last reviewed: May 2014.
1. National diabetes fact sheet: national estimates and general information on diabetes and prediabetes in the United States, 2011. Atlanta, GA: US DHHS, CDC; 2011. -- 2. American Diabetes Association. Standards of Medical Care in Diabetes—2014. Diabetes Care 2014;37:S14-S80. -- 3. Inzucchi SE, Bergenstal RM, Buse JB, et al. Management of hyperglycemia in type 2 diabetes: a patient-centered approach: position statement of the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD). Diabetes Care 2012;35:1364-79. -- 4. Warshaw HS. Nutrition therapy for adults with type 2 diabetes. In: Franz MJ, Evert AB, eds. American Diabetes Association Guide to Nutrition Therapy for Diabetes. 2nd ed. Alexandria, VA: American Diabetes Association; 2012. -- 5. McCulloch DK, Robertson RP. Risk factors for type 2 diabetes mellitus. Nathan DM, Wolfsdorf JI, Mulder JE, eds. UptoDate. Wolters Kluwer Health. Accessed at: 2013. -- 6. Diabetes Prevention Program (DPP). US Department of Health and Human Services. NIH Publication No. 09-5099. October 2008.