Prediabetes

	Topic Overview
	Health Tools
	Frequently Asked Questions
	Cause
	Symptoms
	What Happens
	What Increases Your Risk
	When to Call a Doctor
	Exams and Tests
	Treatment Overview
	Prevention
	Home Treatment
	Medications
	Other Treatment
	Other Places To Get Help
	Related Information
	References
	Credits

What is prediabetes?

Prediabetes is also referred to as impaired glucose tolerance or impaired fasting glucose. It is a warning sign that you are at risk for developing type 2 diabetes. Most people who get type 2 diabetes have prediabetes first.

Type 2 diabetes is a lifelong disease in which the body does not make enough of the hormone insulin or does not respond to it properly. Over time, type 2 diabetes can lead to serious complications such as heart and large blood vessel disease, stroke, impaired vision, and nerve and kidney disease.

The American Diabetes Association (ADA) estimates that over 40 million Americans between the ages of 40 and 74 have prediabetes; however, prediabetes affects younger people as well.¹ Research indicates that each year between 4% and 9% of people with prediabetes go on to develop type 2 diabetes.² Compared with people who have normal blood sugar levels, people with prediabetes have a higher risk of getting cardiovascular disease.³

What causes prediabetes?

Prediabetes, like type 2 diabetes, occurs when the body does not respond properly to insulin and therefore cannot keep blood sugar levels within a normal range.

The food you eat turns into blood glucose, or sugar. The bloodstream transports glucose to all the cells in your body to be used for energy. Normally, the pancreas produces insulin, which allows the sugar in the blood to enter the body's cells. When your body's tissues are not responding properly to insulin, it becomes difficult for cells to get glucose from the blood for energy. This is called insulin resistance. When this happens, the cells cannot use the glucose, which then remains in the blood.

The buildup of sugar in the blood causes prediabetes. Over time, if not treated, the condition may get worse and lead to type 2 diabetes and serious complications such as heart and large blood vessel disease, stroke, and nerve and kidney disease.

What are the symptoms?

Prediabetes is most often a silent condition with no symptoms.

However, certain risk factors, such as a family history of diabetes, obesity, or lack of exercise, put you at a higher risk of getting prediabetes and eventually type 2 diabetes. Although you may still be healthy, moderately and persistently elevated blood sugar levels greatly increase your risk for getting diabetes and heart and blood vessel (cardiovascular) disease.

How is prediabetes diagnosed?

A diagnosis of prediabetes is based on a medical history, a physical examination, and the results of blood sugar tests. Most likely you discovered that you have prediabetes when you saw a health professional for a regular medical checkup or an appointment for another illness or condition.

A health professional may diagnose prediabetes when fasting blood glucose (sugar) levels are between 100 and 125 milligrams per deciliter (mg/dL).

How is it treated?

Treatment for prediabetes focuses mainly on eating a healthy diet that spreads carbohydrate throughout the day; eating foods low in saturated fat and high in soluble fiber; losing weight; and getting regular exercise. These measures may sound simple, but they are very important for your health and for preventing diabetes.

Your health professional may prescribe medicine in addition to diet and exercise. But research has shown promising results in preventing diabetes through diet and exercise alone.^{4, 5}

Can prediabetes be prevented?

The good news is that by making certain lifestyle changes you can prevent prediabetes as well as avoid or delay the progression to full-blown type 2 diabetes. Eating a healthy diet that spreads carbohydrate throughout the day, choosing foods low in saturated fat and high in soluble fiber, getting regular exercise, and losing weight can also reduce your risk of getting other serious conditions such as coronary artery disease and stroke.

Health tools help you make wise health decisions or take action to improve your health.

	Actionsets are designed to help people take an active role in managing a health condition.
	Using a plate format for people with diabetes

Prediabetes occurs when the body does not respond properly to the hormone insulin and therefore cannot keep blood glucose (sugar) levels within a normal range. Blood sugar is higher than normal, but not high enough to be diabetes.

The food you eat turns into blood glucose, or sugar. The bloodstream transports glucose to all the cells in your body to be used for energy. Normally, the pancreas produces insulin, which allows the sugar in the blood to enter the body's cells. When your body's tissues are not responding properly to insulin, it becomes difficult for cells to get glucose from the blood for energy. This is called insulin resistance. When this happens, the cells cannot use the glucose, which then remains in the blood.

The buildup of sugar in the blood causes prediabetes. Over time, if not treated, the condition may get worse and lead to type 2 diabetes and other serious complications such as heart and large blood vessel disease, stroke, impaired vision, and nerve and kidney disease.

Prediabetes is most often a silent condition with no symptoms.

However, certain risk factors, such as obesity or lack of exercise, may put you at a higher risk of developing prediabetes. If you have any of the risk factors for prediabetes—which are similar to the risk factors for type 2 diabetes—ask your health professional whether you should be tested.

Being diagnosed with prediabetes is a warning sign that you are at risk for developing type 2 diabetes. Each year about 4% to 9% of people with prediabetes go on to develop type 2 diabetes.² Although you may still be healthy, moderate and persistent elevated blood sugar levels greatly increase your risk for getting diabetes and heart and blood vessel (cardiovascular) disease. Compared to people with normal blood sugar levels, people with prediabetes have a higher risk of developing cardiovascular disease.³

If you have been diagnosed with prediabetes, you are also at higher risk for eye, nerve, and kidney disease. For more information on these complications, see the topic Type 2 Diabetes: Living With the Complications.

You can help prevent or delay the onset of type 2 diabetes by doing all of the following:

• Limit the amount of fat you eat.
• Limit the calories you eat.
• Limit and spread carbohydrate throughout the day.
• Limit sweets.
• Lose weight.
• Get regular exercise.

These healthy habits can also lower your risk of complications. For more information, see the Treatment Overview section of this topic.

The risk factors for prediabetes are similar to the risk factors for type 2 diabetes. Most people who get type 2 diabetes had prediabetes first.

Risk factors that you cannot control include:

• Family history. People who have a parent, brother, or sister with prediabetes or type 2 diabetes have a greater chance of developing these conditions. In the United States, adults who have a parent with type 2 diabetes are four times more likely to develop the disease than adults without a parental history of the disease. The risk is nearly eight times higher when both parents have type 2 diabetes.⁶
• Age. The risk for getting prediabetes and type 2 diabetes increases with age. The American Diabetes Association estimates that over 40 million Americans age 40 to 74 have prediabetes.¹ However, the number of children being diagnosed with type 2 diabetes is increasing. Usually, children who get type 2 diabetes have a family history of the disease, are overweight, and are physically inactive.⁷
• Race and ethnicity. African Americans, Hispanics, Native Americans, Asian Americans, and Pacific Islanders are at higher risk for type 2 diabetes than whites.⁸
• History of gestational diabetes or having a baby weighing more than 9 lb (4 kg). Women who have had gestational diabetes or who have had a large baby are at higher risk for developing type 2 diabetes later in life.⁸
• Low birth weight. People who weighed less than 5.5 lb (2.5 kg) at birth are more likely to develop type 2 diabetes later in life.⁶

Risk factors that you can change or get treatment for include:

• Being overweight. The risk for prediabetes and type 2 diabetes increases as weight (or body mass index, BMI) increases. People who have a large percentage of body fat in the abdominal area—waist circumference greater than 40 in. (102 cm) in men and greater than 35 in. (88 cm) in women—are at higher risk for type 2 diabetes, even if their BMI is within the normal range.⁹ In addition, weight gain of more than 22 lb (10 kg) after age 18 in women or 18 lb (8 kg) after age 21 in men further raises the risk for type 2 diabetes.⁶
• Lack of physical exercise. Participating in physical exercise less than once a week raises your chance of developing type 2 diabetes by 20% to 40%.⁶ One large study found that women who were sedentary, especially those who watched a lot of television, were at higher-than-average risk of obesity and type 2 diabetes.¹⁰
• High blood pressure (hypertension). People who have blood pressure levels above 140/90 millimeters of mercury (mm Hg) are at greater risk for prediabetes and type 2 diabetes than people who have normal blood pressure.⁸
• Abnormal cholesterol. People who have high-density lipoprotein (HDL) cholesterol levels of 35 milligrams per deciliter (mg/dL) or less or triglyceride levels of 250 mg/dL or more are at higher risk for getting type 2 diabetes.⁸
• An unhealthy diet. A diet high in sugary foods and low in fiber content raises your risk for prediabetes and type 2 diabetes.⁶ One large study found that a diet high in red meat, processed meat, high-fat dairy products, french fries, refined grains, and sweets increased men's risk for type 2 diabetes compared with a diet high in vegetables, fruits, fish, poultry, and whole grains.¹¹

Other risk factors for prediabetes and type 2 diabetes, which are also associated with obesity and a lack of physical activity, include:

• Having polycystic ovary syndrome (PCOS), a hormone imbalance that interferes with normal ovulation.
• Having metabolic syndrome, a group of abnormal physical findings related to the body's metabolism.

If you have prediabetes, you are more likely to get cardiovascular disease than someone with normal blood glucose levels.³ By lowering your cholesterol to the recommended levels, not smoking, and keeping your blood pressure under 140/90 millimeters of mercury (mm Hg), you may reduce your risk of heart and large blood vessel disease.

The American Diabetes Association recommends screening for prediabetes—which may lead to type 2 diabetes—if you:³

• Are 45 years of age or older—particularly if you are overweight— and you have never had your blood glucose (sugar) tested or you have not been tested in more than 3 years.
• Are younger than 45, overweight—body mass index, BMI, of 25 or greater—and have one or more other risk factors for type 2 diabetes. These include:
  • High blood pressure, over 140/90 millimeters of mercury (mm Hg).
  • Abnormal cholesterol. People who have high-density lipoprotein (HDL) cholesterol levels of 35 milligrams per deciliter (mg/dL) or less or triglyceride levels of 250 mg/dL or more are at higher risk for getting type 2 diabetes.⁸
  • A family history of type 2 diabetes. People who have a parent, brother, or sister with prediabetes or type 2 diabetes have a greater risk of getting the disease than adults without a parental history of the disease.
  • History of gestational diabetes or having a baby weighing more than 9 lb (4 kg). Women who have had gestational diabetes or who have had a large baby are at greater-than-average risk for getting type 2 diabetes later in life.⁸
  • Race and ethnicity. African Americans, Hispanics, Native Americans, Asian Americans, and Pacific Islanders are at greater risk for getting type 2 diabetes than whites.⁸
• Are overweight and get little or no exercise and want to help reduce your risk for getting type 2 diabetes.

Your health professional will use a medical history, physical examination, and blood glucose testing to determine whether you have prediabetes and are at risk for developing type 2 diabetes.

Blood glucose testing is usually done after fasting overnight for 8 hours. In some cases, an oral glucose tolerance test (OGTT) may be done. For an OGTT your blood sugar is measured after fasting and then again 2 hours after drinking a special glucose solution. This test is not done as often as the fasting glucose test, which is more convenient.

If the results of your glucose tests are in one of the following ranges, you have prediabetes and are at risk of developing type 2 diabetes:

• Fasting glucose of 100 to 125 milligrams per deciliter (mg/dL)
• Oral glucose tolerance (OGT) of 140 to 199 mg/dL (2 hours after the beginning of the test)

Phrases such as "a touch of diabetes,” “borderline diabetes,” or “your sugar is a little high” are unclear. If you hear these phrases, ask whether your blood sugar level falls within the prediabetes or diabetes range.

If you are diagnosed with prediabetes or type 2 diabetes, your health professional may also do a thorough examination of the cardiovascular system and check your blood pressure and cholesterol levels. Your health professional may also test your blood sugar periodically to check for diabetes.

Early Detection

The American Diabetes Association recommends screening for prediabetes—which may lead to type 2 diabetes—if you³:

• Are 45 years of age or older—particularly if you are overweight—and you have never had your blood glucose (sugar) tested or you have not been tested in more than 3 years.
• Are younger than 45, overweight—body mass index, BMI, of 25 or greater—and have one or more other risk factors for type 2 diabetes. These include:
  • High blood pressure, over 140/90 millimeters of mercury (mm Hg).
  • Abnormal cholesterol. People who have high-density lipoprotein (HDL) cholesterol levels of 35 milligrams per deciliter (mg/dL) or less or triglyceride levels of 250 mg/dL or more are at increased risk for developing type 2 diabetes.⁸
  • A family history of type 2 diabetes. People who have a parent, brother, or sister with prediabetes or type 2 diabetes have a greater risk of developing the disease than adults without a parental history of the disease.
  • History of gestational diabetes or having a baby weighing more than 9 lb (4 kg). Women who have had gestational diabetes or who have had a large baby are at greater risk for getting type 2 diabetes later in life.⁸
  • Race and ethnicity. African Americans, Hispanics, Native Americans, Asian Americans, and Pacific Islanders are at greater risk for getting type 2 diabetes than whites.⁸
• Are overweight and get little or no exercise and want to help reduce your risk for getting type 2 diabetes.

If you have been diagnosed with prediabetes, you will play a key role in your treatment and have an opportunity to reverse the condition or delay the progression to type 2 diabetes. Losing weight, eating a healthy diet, and getting regular exercise are very effective in preventing or delaying the onset of diabetes as well as lowering your risks for other complications, such as coronary artery disease or stroke. These measures may sound simple, but they are very important for your overall health and for preventing diabetes.

In some cases, your health professional may prescribe medicine in addition to diet and exercise. But recent research has shown promising results in preventing diabetes through diet and exercise alone. One large study done in the U.S. (Diabetes Prevention Program) showed that making these lifestyle changes was more effective at lowering the risk of getting type 2 diabetes than taking medicine:⁴

• Those who lost a modest amount of weight (5% to 10% of total body weight) and exercised lowered their risk by 58%.
• Those who took medicine lowered their risk by 31%.

Monitor your weight

Most people with prediabetes are overweight—body mass index, BMI, of 25 or greater. If you have a BMI of 25 or higher, losing just 5% to 10% of your body weight may help you prevent or delay type 2 diabetes.¹² A healthy weight helps your body use insulin properly. One recent study showed that losing weight improves insulin resistance in people with prediabetes. The degree of improvement is related to the amount of weight lost.¹³ For more information on determining your BMI, see:

• Body mass index (BMI) chart for adults .
• Body mass index (BMI) for adults (metric) .

Eat a balanced diet

If you have prediabetes, you may be able to prevent or delay the disease by doing all of the following:

• Limit the amount of fat you eat. Eat foods low in saturated fat and high in soluble fiber
• Eat less calories.
• Spread carbohydrate throughout the day and limit sweets to avoid sudden peaks in blood sugar. Of the three major nutrients (carbohydrate, protein, and fat), carbohydrate has the greatest effect on blood sugar.

Talk to your health professional about developing a plan for healthy eating.

One large study found that men who ate a diet high in vegetables, fish, poultry, and whole grains had a lower risk for getting type 2 diabetes compared with men who ate a diet high in red meat, processed meat, high-fat dairy foods, refined grains, and sweets.¹¹

Planning meals to manage prediabetes often means looking at food in a new way. There are several easy ways to adapt your diet. A registered dietitian can help you build a meal plan that fits your lifestyle. For more information on one type of meal planning, see:

Using a plate format.

Exercise regularly

Get at least 30 minutes of exercise on most days. Exercise helps control your blood sugar by using glucose for energy during and after activity. Exercise helps your body respond better to insulin and lowers your risk of getting diabetes. It also helps you maintain a healthy weight; lower high cholesterol; raise high-density lipoprotein (HDL), or "good," cholesterol; and lower high blood pressure. These benefits also help prevent heart and blood vessel (cardiovascular) disease. You may lower your risk of getting diabetes even more by exercising for longer periods of time during each exercise session.

Exercise can consist of moderate walking or more vigorous activities such as jogging, running, bicycling, or playing tennis. Research has also shown that other activities, such as gardening or snow shoveling may be beneficial.⁵ Work with your health professional to plan a safe exercise program.

Take medicine if needed

In some cases a health professional may prescribe an oral medicine—most commonly metformin—to help improve metabolism in insulin-resistant patients. This may be appropriate in people with polycystic ovary syndrome. If your doctor has prescribed medicine for prediabetes, be sure to take it as directed.

Stop smoking

If you smoke cigarettes, talk with a health professional about ways to quit. Smoking may play a role in the development of type 2 diabetes, and it contributes to early development of diabetes complications.¹⁴ For more information on how to quit, see the topic Quitting Tobacco Use.

Monitor blood pressure and cholesterol levels

If you have prediabetes you are more likely to get cardiovascular disease than someone with normal blood glucose levels.³ Your health professional may take your blood pressure and test your blood periodically to check your cholesterol levels. By lowering your cholesterol to the recommended levels and keeping your blood pressure under 140/90 millimeters of mercury (mm Hg), you may reduce your risk of heart and large blood vessel disease.

By eating a healthy diet and getting regular exercise, you may be able to keep your blood pressure and cholesterol levels within the recommended ranges. People who have high-density lipoprotein (HDL) cholesterol levels of 35 milligrams per deciliter (mg/dL) or less or triglyceride levels of 250 mg/dL or more are at higher risk for getting type 2 diabetes.⁸

If you have any of the risk factors for prediabetes, you can take steps to prevent this condition as well as the progression to full-blown type 2 diabetes. The best ways to prevent prediabetes are:

• Managing your weight.
• Eating a healthy diet.
• Getting regular exercise.

You can play a key role in controlling your blood sugar levels by:

• Losing weight if you are overweight. Studies have shown that losing just 5% to 10% of your body weight may help you prevent or at least delay type 2 diabetes.¹² A healthy weight helps your body use insulin properly. One recent study showed that losing weight improves insulin resistance in people with prediabetes. The degree of improvement is related to the amount of weight lost.¹³ For more information on weight and body mass index (BMI), see the body mass index (BMI) chart for adults or the same chart in metric .
• Limiting fat and eating a balanced diet by limiting carbohydrate throughout the day to avoid sudden peaks in blood sugar and by eating foods low in saturated fat and high in soluble fiber. Talk to your health professional about making a plan for healthy eating.
  • One large study found that men who ate a diet high in vegetables, fish, poultry, and whole grains had a lower risk for getting type 2 diabetes compared with men who ate a diet high in red meat, processed meat, high-fat dairy foods, refined grains, and sweets.¹¹
• Exercising. Exercise helps control your blood sugar by using glucose for energy during and after activity. Exercise helps your body respond better to insulin and lowers your risk of getting diabetes. It also helps you maintain a healthy weight; lower high cholesterol; raise high-density lipoprotein (HDL), or "good," cholesterol; and lower high blood pressure. These benefits also help prevent cardiovascular disease. If you do not get regular exercise, talk with your health professional about beginning an exercise program. Lack of regular exercise raises the chances that your blood sugar level will increase from normal to prediabetes to type 2 diabetes. Any type of physical activity may be beneficial, including:^{5, 15, 16}
  • Sports or other types of exercise, such as walking, jogging, swimming, or biking.
  • Household work, such as vacuuming or gardening.
  • Work-related activities.

The National Diabetes Education Program's Small Steps Big Rewards program outlines several ways to make minor changes to your lifestyle that can have a big impact on preventing prediabetes and type 2 diabetes. These include setting goals for moderate weight loss and exercise and tracking your progress. For more information about this program, visit the National Diabetes Education Program web site: http://www.ndep.nih.gov/.

If you smoke cigarettes, talk with a health professional about ways to quit. Smoking may play a role in the development of type 2 diabetes, and it contributes to early development of diabetes complications.¹⁴ For more information, see the topic Quitting Tobacco Use.

Several studies have shown that home treatment for prediabetes is the most effective way to treat prediabetes and prevent the progression to type 2 diabetes.^{5, 4} Home treatment consists of:

• Monitoring your weight.
• Eating a healthy diet.
• Exercising regularly.

Monitor your weight.

Most people with prediabetes are overweight (body mass index [BMI] of 25 or greater). If you have a BMI of 25 or higher, losing just 5% to 10% of your body weight may help you prevent or delay type 2 diabetes.¹² A healthy weight helps your body use insulin properly. One recent study showed that losing weight improves insulin resistance in people with prediabetes. The degree of improvement is related to the amount of weight lost.¹³ For more information on determining your BMI, see:

• Body mass index (BMI) chart for adults .
• Body mass index (BMI) chart for adults (metric) .

Eat a balanced diet.

If you have prediabetes, you may be able to prevent or delay the disease by eating a balanced diet that limits fat and spreads carbohydrate throughout the day to avoid sudden peaks in blood sugar. Of the three major nutrients (carbohydrate, protein, and fat), carbohydrate has the greatest effect on blood sugar.

Limit fat in your diet. Eat foods low in saturated fat and high in soluble fiber. Talk to your health professional about developing a plan for healthy eating.

Planning meals to manage prediabetes often means looking at food in a new way. There are several easy ways to adapt your diet. A registered dietitian can help you make a meal plan that fits your lifestyle. For more information on one type of meal planning, see:

Using a plate format.

Exercise regularly.

Get at least 30 minutes of exercise on most days. Exercise helps control your blood sugar by using glucose for energy during and after activity. Exercise helps your body respond better to insulin and lowers your risk of getting diabetes. It also helps you maintain a healthy weight; lower high cholesterol; raise high-density lipoprotein (HDL), or "good," cholesterol; and lower high blood pressure. These benefits also help prevent cardiovascular disease. You may lower your risk of getting diabetes even more by exercising for longer periods of time during each exercise session.

If you do not get regular exercise, talk with your health professional about beginning an exercise program. Lack of regular exercise raises the risk that your blood sugar level will increase from normal to prediabetes to type 2 diabetes. Any type of physical activity may be beneficial, including:^{5, 15, 16}

• Sports or other types of exercise, such as walking, jogging, swimming, or biking.
• Household work, such as vacuuming or gardening.
• Work-related activities.

The National Diabetes Education Program's Small Steps Big Rewards program outlines several ways to make minor adjustments to your lifestyle that can have a big impact on preventing type 2 diabetes. These include setting goals for moderate weight loss and exercise and tracking your progress. For more information about this program, visit the National Diabetes Education Program Web site at http://www.ndep.nih.gov/.

If you smoke cigarettes, talk with a health professional about ways to quit. Smoking may play a role in the development of type 2 diabetes, and it contributes to early development of diabetes complications.¹⁴ For more information on how to quit, see the topic Quitting Tobacco Use.

Most people with prediabetes get better results by making lifestyle changes, such as losing weight, eating a healthy diet, and getting regular exercise, than with diabetes medicine.⁴

However, a health professional may prescribe a biguanide, usually metformin (Glucophage), because it can reduce insulin resistance—especially in patients with polycystic ovary syndrome. In some cases a health professional may prescribe thiazolidinediones (Actos or Avandia) to lower insulin resistance. Metformin is used much more frequently.

Ask your health professional whether diet and exercise are sufficient treatment or whether you should take medicine to lower your insulin resistance.

Avoid products that promise a cure for prediabetes and are advertised only by testimonials of satisfied customers. These products or remedies may be harmful and costly. The best way to treat prediabetes is by eating a healthy diet and getting regular exercise.

If you have questions about a product for prediabetes or diabetes, check with your local American Diabetes Association office, your doctor, or a diabetes educator.

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