Type 2 Diabetes

Topic Overview

Is this topic for you?

This topic has general information about type 2 diabetes for people who do not have the disease. If you want to learn how to manage type 2 diabetes, one of the following topics may meet your needs:

If you are looking for information about type 1 diabetes, see the topic Type 1 Diabetes.

What is type 2 diabetes?

Type 2 diabetes is a lifelong disease that happens when the cells of the body can't use insulin the right way or when the pancreas can't make enough insulin. Insulin lets blood sugar—also called glucose—enter the body’s cells to be used for energy. When insulin is not able to do its job, the cells can't get the sugar they need, and too much sugar builds up in the blood. Over time, this extra sugar in the blood can damage your eyes, heart, blood vessels, nerves, and kidneys.

More and more adults and children are getting type 2 diabetes. This is largely because of bad eating habits and a lack of physical activity. It is important to know if you or your children are at risk for type 2 diabetes and to know what you can do to help prevent the disease.

What causes type 2 diabetes?

You can get type 2 diabetes if:

  • Your body does not respond as it should to insulin. This makes it hard for your cells to get sugar from the blood for energy. This is called insulin resistance.
  • Your pancreas does not make enough insulin.

Your weight, how active you are, and your family history all affect the way your body responds to insulin. If you are overweight, get little or no exercise, or have family members with diabetes, you have a greater chance of getting type 2 diabetes.

What are the symptoms?

Some people don't have symptoms, especially when diabetes is diagnosed early. This is because the blood sugar level may rise so slowly that a person may not know that anything is wrong. Other people may have symptoms, such as:

  • Being very thirsty.
  • Urinating a lot.
  • Losing weight without trying.
  • Having blurry vision.
  • Feeling hungrier or more tired than usual.

Sometimes a person finds out during a regular medical checkup that he or she has type 2 diabetes. Or people may find out that they have the disease during an appointment for another health problem such as high blood pressure, an infection, or a wound that heals slowly. Some people don't find out that they have diabetes until they have a complication from the disease, such as vision problems, kidney disease, nerve disease, or heart and blood vessel problems.

How is type 2 diabetes diagnosed?

If your doctor thinks that you have type 2 diabetes, he or she will ask you questions about your medical history, do a physical exam, and order a blood test that measures the amount of sugar in your blood.

How is it treated?

The key to treating type 2 diabetes is controlling blood sugar levels. All of the following help to lower blood sugar:

  • Eating healthy foods
  • Losing weight, if you are overweight
  • Getting regular exercise
  • In some cases, taking medicines

Treatment for diabetes also includes checking blood sugar levels to make sure that the disease is under control. It is important to watch for signs of high and low blood sugar. Both can cause problems and need to be treated.

People with diabetes need regular checkups to make sure that the treatment is working and that they do not get more serious health problems.

Can type 2 diabetes be prevented?

If you are at risk for type 2 diabetes or if you have prediabetes, you may prevent diabetes by getting regular exercise and paying attention to what and how much you eat. If you are overweight, losing a little weight (10 to 20 pounds) can go a long way toward preventing or delaying the disease.

Cause

You can develop type 2 diabetes if:

  • Your body does not respond properly to insulin, making it difficult for your cells to get sugar from the blood to make energy. This is called insulin resistance.
  • Your pancreas does not make enough insulin.

Your weight, how much physical activity you get, and your family history all affect the way your body responds to insulin. If you are overweight, get little or no exercise, or have family members with diabetes, you have a greater chance of developing type 2 diabetes.

Symptoms

At first, your blood sugar level may rise so slowly that you may not know that anything is wrong. One-third of all people who have diabetes do not know that they have the disease.1

If you do have symptoms of type 2 diabetes, they may include:

  • Feeling thirsty.
  • Having to urinate more than usual.
  • Feeling more hungry than usual.
  • Losing weight without trying to.
  • Feeling very tired.
  • Feeling cranky.

Other signs of type 2 diabetes may include:

  • Infections and cuts and bruises that heal slowly.
  • Blurred vision.
  • Tingling or numbness in your hands or feet.
  • Trouble with skin, gum, or bladder infections.
  • Vaginal yeast infections.

Some people have already developed more serious health problems by the time they are diagnosed with type 2 diabetes. Over time, diabetes can lead to problems with the eyes, kidneys, heart, blood vessels, and nerves. Signs of these problems may include:

  • Numbness, tingling, burning pain, or swelling in your feet or hands (diabetic neuropathy).
  • Blurred or distorted vision or seeing flashes of light; seeing large, floating red or black spots; or seeing large areas that look like floating hair, cotton fibers, or spiderwebs (diabetic retinopathy).
  • Chest pain or shortness of breath. This may be a sign of heart or blood vessel problems.

What Happens

Type 2 diabetes is a lifelong disease that affects the way your body uses food for energy. The disease develops when the cells of the body become resistant to insulin or when the pancreas cannot make enough insulin. Insulin is a hormone that helps your body's cells get needed energy from sugar. When insulin is not able to do its job, too much sugar builds up in your blood. Over time, this extra sugar in your blood can lead to problems with your eyes, heart, blood vessels, nerves, and kidneys.

Type 2 diabetes usually develops in adulthood. But more and more children are being diagnosed with type 2 diabetes. Often people who have type 2 diabetes are overweight and get little or no physical exercise.

Sometimes type 2 diabetes develops so slowly that you do not have symptoms until you already have some more serious problems from the disease. Many people have prediabetes—when blood sugar levels are above normal but not high enough to have diabetes—for years before they know they develop type 2 diabetes. For more information on prediabetes, see the topic Prediabetes.

After you know that you have type 2 diabetes, you will work with your doctor and other health professionals to develop the best treatment plan for you. Treatment usually includes eating healthy foods and spreading carbohydrate throughout the day, exercising regularly, checking your blood sugar levels often, and possibly taking medicine. Working closely with your doctor and other health professionals can help you feel better and more in control of your disease. You can help prevent or delay more serious health problems by keeping your blood sugar within your target blood sugar range.

As time goes on, your pancreas may make less and less insulin, which can make it harder to control your blood sugar level. It is important to treat your high blood sugar early anytime your blood sugar level rises above what is safe for you. Treating high blood sugar early can help prevent:

  • A hyperosmolar state, which is a life-threatening event that can happen when the blood sugar level is very high. It can occur when a person with type 2 diabetes has an illness, such as a severe case of the flu or other infection; has a heart attack; is not drinking enough liquids and becomes dehydrated; or takes medicines (diuretics) that increase fluid loss or affect mental alertness, especially if liquids are not replaced.
  • Long-term diabetes complications, which result from damage to the body's tissues. Persistent high blood sugar can damage the eyes (diabetic retinopathy), kidneys (diabetic nephropathy), nerves (diabetic neuropathy), heart (leading to a heart attack), and blood vessels (leading to strokes, peripheral arterial disease, and possibly amputation).

What Increases Your Risk

There are some things that you cannot change that increase your chances of getting type 2 diabetes:

Risk factors that you cannot control include:2

  • Family history . If you have a parent, brother, or sister who has type 2 diabetes, you have a greater chance of developing the disease.
  • Age. The risk for getting prediabetes and type 2 diabetes increases with age. And 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.
  • Race and ethnicity. African Americans, Hispanics, Native Americans, Asian Americans, and Pacific Islanders are at higher risk than whites for type 2 diabetes.
  • 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.
  • 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.

Other conditions that put you at risk for type 2 diabetes—and that are also linked to obesity and a lack of physical activity—include:

If you are concerned about diabetes, you can take a test to determine your risk of getting the disease. If you are at risk, you can discuss with your doctor how to make healthy changes in your life. If you want, your doctor can refer you to health professionals who are trained to help you make your own easy-to-follow plan for eating and exercising. No matter how and when you start, it is important to remember that even small changes can lower your chances of developing diabetes.

When to Call a Doctor

Call your doctor about type 2 diabetes if you:

  • Are age 45 or older and you have never been tested for type 2 diabetes or you have not been tested in more than 3 years.
  • Are younger than 45, are at high risk for type 2 diabetes, and want to be tested.
  • Have one or more of the common symptoms of diabetes, such as increased thirst, frequent urination, increased hunger, unusual weight loss, or extreme fatigue.
  • Have other signs that you may have type 2 diabetes, such as wounds that are not healing well or frequent infections.
  • Have not been diagnosed with type 2 diabetes but notice symptoms of complications from the disease, such as:
    • Having burning pain, numbness, or swelling in your feet or hands.
    • Feeling dizzy or weak when you sit up or stand up suddenly.
    • Seeing flashing lights; seeing large, floating red or black spots; or seeing large areas that look like floating hair, cotton fibers, or spiderwebs.
  • Are overweight, get little or no exercise, and want help to reduce your risk for developing type 2 diabetes.
  • Have been told that your blood sugar level is above the normal range (prediabetes) and you want to know more about decreasing your risk for type 2 diabetes.

Watchful Waiting

If you think you may have symptoms of diabetes, it is not a good idea to ignore them or to wait and see what happens. Type 2 diabetes can get worse and can cause serious problems if it is not diagnosed early. Be sure to talk with your doctor about any symptoms of or concerns you have about type 2 diabetes, especially if you have any risk factors that make it more likely for you to develop the disease.

Who to See

The following health professionals can diagnose diabetes:

Exams and Tests

If your doctor thinks that you may have diabetes, he or she will order blood tests to measure how much sugar is in your blood. The tests used are blood glucose tests and hemoglobin A1c.

To make a diagnosis of type 2 diabetes, your doctor will use your blood test results and the American Diabetes Association's criteria. He or she also will ask you questions about your medical history and do a physical exam.

If your blood sugar level is above normal but below the level for diabetes, you have prediabetes and are at risk for developing type 2 diabetes. For more information on prediabetes, see the topic Prediabetes.

Other tests

A home blood sugar test or a urine test for sugar is not the best way to learn whether you have diabetes. But after you are diagnosed, you may use home blood sugar tests to check your own blood sugar levels.

Along with your home blood sugar tests, your doctor will give you a hemoglobin A1c (glycohemoglobin) test after you start treatment for diabetes. This test finds your average blood sugar level over the previous 2 to 3 months. The A1c test adds to the information from your home blood sugar tests to help you keep track of your blood sugar control.

After you are diagnosed with type 2 diabetes or prediabetes, you may have a thorough exam of your cardiovascular system to check for any heart problems.

Early detection

You can use the American Diabetes Association's risk test for diabetes to see whether you are at risk for type 2 diabetes.

If you are age 45 or older, the American Diabetes Association recommends that you be tested for diabetes every 3 years.2 The United States Preventive Services Task Force (USPSTF) recommends testing for diabetes in people who have blood pressure higher than 135/80.3 Talk with your doctor about your risk factors and how often you need to be tested.

The American Diabetes Association recommends that you be tested more often or begin testing at a younger age if you are overweight (have a body mass index, or BMI, of 25 or higher) and:2

Treatment Overview

It can be scary to learn that you, your child, a family member, or a friend has type 2 diabetes or is at risk for the disease. Many people are shocked when they find out that they have type 2 diabetes. Others are relieved to know what has been causing their symptoms. It is normal to feel angry or depressed about having a serious lifelong disease, but remember that many people who have type 2 diabetes enjoy healthy, active lives when they are able to control their blood sugar. Exercising, eating healthy foods, and taking medicines all help control blood sugar.

There is no cure for type 2 diabetes, but there are ways to treat the disease. Even if you do not feel sick, you still need treatment to prevent more serious health problems.

Some people can control their blood sugar by changing the way they eat and exercising more. Other people also need to take medicines. Treatment for type 2 diabetes includes:

  • Changing the way you eat—to a healthier, more balanced diet.
  • Limiting saturated fats.
  • Limiting alcohol.
  • Limiting calories in order to avoid gaining weight, or to help you lose weight.
  • Exercising regularly to help your body use insulin better.
  • Checking your blood sugar at home to know when the level is above or below your target range.
  • Taking pills, if eating differently and exercising more do not keep your blood sugar levels within your target range. You may need one or more medicines to help your body make more insulin or to use insulin better.
  • Taking insulin shots for a while or for the rest of your life. Insulin is usually given in the form of a shot, and it may be used alone or with other medicines that are in the form of pills or shots.
  • Seeing your doctor regularly to make sure that your treatment is working and that you have not developed any serious problems such as eye, cardiovascular, nerve, or kidney disease.

Other important issues

If you have type 2 diabetes, you also need to:

  • Always wear medical identification to let health professionals know in an emergency that you have diabetes. Medical ID necklaces or bracelets are available from your doctor, your local pharmacy, or online.
  • Know how to recognize and quickly treat high blood sugar and low blood sugar.
  • Take extra care of your skin, teeth, feet, and gums.
  • Know how to care for yourself when you are sick.

For more information on managing type 2 diabetes, see the topics Type 2 Diabetes: Recently Diagnosed and Type 2 Diabetes: Living With the Disease.

Prevention

Preventing type 2 diabetes

You can take steps to prevent type 2 diabetes. Even small changes can make a difference, and it is never too late to start making healthier choices.

  • Maintain a healthy weight. To find out if you are overweight, you can use the body mass index (BMI) chart for adults or the same chart in metric. If you need to lose weight, losing as few as 10 lb (4.5 kg) to 20 lb (9.1 kg) can help reduce your risk of developing diabetes.2
  • Exercise regularly. Getting enough exercise lowers your risk of developing type 2 diabetes.4 Do activities that raise your heart rate. Try to do moderate activity at least 2½ hours a week. Or try to do vigorous activity at least 1¼ hours a week. It's fine to be active in blocks of 10 minutes or more throughout your day and week. Also include resistance exercises in your exercise program.5, 6 Resistance exercises can include activities like weight lifting or even yard work. This does not mean that you have to do strenuous activities or join an expensive gym—anything that increases your heart rate counts. Walking groups or programs where you use a pedometer to count the number of steps you take in a day are great ways to start exercising and to stay motivated. If you are at risk for type 2 diabetes, using an exercise planning form(What is a PDF document?) may help you and your doctor or other health professional to create a personalized exercise program.
  • Eat healthy foods.
    • Eat a balanced diet, including whole grains, lean meat, and vegetables.
    • Limit saturated fats.
    • Limit alcohol.
    • Limit calories in order to avoid gaining weight, or to help you lose weight.
    • Reduce your intake of soft drinks, sugary foods, and junk food.
    • Eat smaller meals more often in order to keep blood sugar levels within your target range.
    Eating more vegetables, whole grains, and nuts can lower your risk for type 2 diabetes.7 Eating a lot of sugary foods, fast foods, and red meat (especially processed red meat) and drinking a lot of soft drinks can increase your risk for type 2 diabetes.8, 9, 10 If you want to learn more about eating well, see the topic Healthy Eating.
  • Get treatment if you have prediabetes . If your fasting blood sugar levels are in the range from 100 mg/dL to 125 mg/dL, you are at increased risk for type 2 diabetes.2

Preventing diabetes complications

You can help prevent or delay problems with your eyes, heart, nerves, and kidneys if you:

  • Keep your blood sugar levels within your target range.
  • Talk to your doctor about taking a low-dose aspirin to prevent a heart attack, a stroke, or other large blood vessel diseases (macrovascular disease).
  • Control your blood pressure and cholesterol levels.
  • Take an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor blocker (ARB) medicine at the first sign of diabetic nephropathy, even if you do not have high blood pressure.2
  • Get regular eye exams.
  • Take good care of your feet.
  • Quit smoking. If you smoke cigarettes, talk with your doctor about ways to quit. Smoking contributes to the early development of diabetes complications.11 For more information, see the topic Quitting Smoking.

Home Treatment

Making healthy choices is a large part of treating type 2 diabetes. The more you learn about the disease, the more motivated you may be to make good choices and to follow your treatment plan. By understanding what is happening in your body, you may also feel more in control of your disease.

If you have type 2 diabetes, your daily routine will include:

  • Eating healthy foods and spreading carbohydrate throughout the day.
  • Getting plenty of physical activity that raises your heart rate, including resistance exercises like weight lifting or even yard work.
  • Checking your blood sugar levels.
  • Taking pills for type 2 diabetes and insulin, or other shots if prescribed.
  • Drinking enough fluids to avoid dehydration.
  • Taking a low-dose aspirin, if your doctor advises you to.

Other important issues

If you have type 2 diabetes, you also need to:

  • Always wear medical identification to let health professionals know in an emergency that you have diabetes. Medical ID necklaces or bracelets are available from your doctor, your local pharmacy, or online.
  • Know how to recognize and to quickly treat high blood sugar and low blood sugar.
  • Take extra care of your skin, teeth, feet, and gums.
  • Know how to care for yourself when you are sick.

For more information on managing type 2 diabetes, see the topics Type 2 Diabetes: Recently Diagnosed and Type 2 Diabetes: Living With the Disease.

Medications

Some people with type 2 diabetes need medicine to help their bodies make more insulin, to decrease insulin resistance, or to slow down how quickly their body absorbs carbohydrate. You may take no medicine, one medicine, or a few medicines. Some people need medicine for short periods of time, while others always need to take medicine. How much medicine you need depends on how well you can keep your blood sugar within your target blood sugar range.

Some people who have type 2 diabetes take medicines for high blood pressure or high cholesterol. They may also take aspirin to prevent a heart attack, a stroke, or other large blood vessel diseases (macrovascular disease).

Surgery

If you are very overweight (BMI greater than 35), weight loss surgery may help you lose weight and improve your diabetes control.2 For more information about weight loss surgeries, see the topic Obesity.

Other Treatment

You may be tempted to try products or pills that promise to cure your type 2 diabetes. But these products and remedies can be harmful and expensive. If you are thinking about taking any medicines or herbal remedies without a prescription, talk to your doctor first.

Other Places To Get Help

Organizations

American Diabetes Association (ADA)
1701 North Beauregard Street
Alexandria, VA  22311
Phone: 1-800-DIABETES (1-800-342-2383)
E-mail: AskADA@diabetes.org
Web Address: www.diabetes.org
 

The American Diabetes Association (ADA) is a national organization for health professionals and consumers. Almost every state has a local office. ADA sets the standards for the care of people with diabetes. Its focus is on research for the prevention and treatment of all types of diabetes. ADA provides patient and professional education mainly through its publications, which include the monthly magazine Diabetes Forecast, books, brochures, cookbooks and meal planning guides, and pamphlets. ADA also provides information for parents about caring for a child with diabetes.


National Diabetes Education Program (NDEP)
1 Diabetes Way
Bethesda, MD  20814-9692
Phone: 1-800-438-5383 to order materials
(301) 496-3583
E-mail: ndep@mail.nih.gov
Web Address: http://ndep.nih.gov
 

The National Diabetes Education Program (NDEP) is sponsored by the U.S. National Institutes of Health (NIH) and the U.S. Centers for Disease Control and Prevention (CDC). The program's goal is to improve the treatment of people who have diabetes, to promote early diagnosis, and to prevent the development of diabetes. Information about the program can be found on two Web sites: one managed by NIH (http://ndep.nih.gov) and the other by CDC (www.cdc.gov/team-ndep).


National Diabetes Information Clearinghouse (NDIC)
1 Information Way
Bethesda, MD  20892-3560
Phone: 1-800-860-8747
Fax: (703) 738-4929
TDD: 1-866-569-1162 toll-free
E-mail: ndic@info.niddk.nih.gov
Web Address: http://diabetes.niddk.nih.gov
 

This clearinghouse provides information about research and clinical trials supported by the U.S. National Institutes of Health. This service is provided by the National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), a part of the National Institutes of Health (NIH).


References

Citations

  1. American Diabetes Association (2008). All About Diabetes. Available online: http://www.diabetes.org/about-diabetes.jsp.
  2. American Diabetes Association (2009). Standards of medical care in diabetes. Clinical Practice Recommendations 2009. Diabetes Care, 32(Suppl 1): S13–S61.
  3. U.S. Preventive Services Task Force (2008). Screening for type 2 diabetes mellitus in adults: U.S. Preventive Services Task Force recommendation statement. Annals of Internal Medicine, 148(11): 846–854.
  4. Diabetes Prevention Program Research Group (2002). Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. New England Journal of Medicine, 346(6): 393–403.
  5. Sigal RJ, et al. (2006). Physical activity/exercise and type 2 diabetes: A consensus statement from the American Diabetes Association. Diabetes Care, 29(6): 1433–1438.
  6. U.S. Department of Health and Human Services (2008). 2008 Physical Activity Guidelines for Americans (ODPHP Publication No. U0036). Washington, DC: U.S. Government Printing Office. Available online: http://www.health.gov/paguidelines/pdf/paguide.pdf.
  7. American Diabetes Association (2004). Magnesium intake and risk of type 2 diabetes in men and women. Diabetes Care, 27(Suppl 1): 134–140.
  8. Funt TT, et al. (2004). Dietary patterns, meat intake, and the risk of type 2 diabetes in women. Archives of Internal Medicine, 164(20): 2235–2240.
  9. Pereira MA, et al. (2005). Fast-food habits, weight gain, and insulin resistance (the CARDIA study): 15-year prospective analysis. Lancet, 365(9453): 36–42.
  10. Schulze MB, et al. (2004). Sugar-sweetened beverages, weight gain, and incidence of type 2 diabetes in young and middle-aged women. JAMA, 292(8): 927–934.
  11. American Diabetes Association (2004). Smoking and diabetes. Clinical Practice Recommendations 2004. Diabetes Care, 27(Suppl 1): S74–S75.

Other Works Consulted

  • American Diabetes Association (2004). A prospective study of red meat consumption and type 2 diabetes in middle-aged and elderly women. Diabetes Care, 27(9): 2108–2115.
  • American Diabetes Association (2004). Nutrition principles and recommendations in diabetes. Position Statement 2004. Diabetes Care, 27(Suppl 1): S36–S46.
  • American Diabetes Association (2004). Prevention or delay of type 2 diabetes. Clinical Practice Recommendations 2004. Diabetes Care, 27(Suppl 1): S47–S50.
  • Hu FB, et al. (2003). Television watching and other sedentary behaviors in relation to risk of obesity and type 2 diabetes mellitus in women. JAMA, 289(14): 1785–1791.
  • Van Dam RM, et al. (2002). Dietary patterns and risk for type 2 diabetes mellitus in U.S. men. Annals of Internal Medicine, 136(3): 201–209.

Credits

Author Christine Wendt, R.D., L.D.
Editor Susan Van Houten, RN, BSN, MBA
Associate Editor Pat Truman, MATC
Primary Medical Reviewer Caroline S. Rhoads, MD - Internal Medicine
Specialist Medical Reviewer Matthew I. Kim, MD - Endocrinology & Metabolism
Last Updated July 15, 2009

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