Prediabetes

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People who have diabetes are unable to produce or unable to properly use and store glucose, a form of sugar found in foods and used by the body's cells for energy. As a result, glucose accumulates in the bloodstream, and the person's blood glucose rises too high. In type 1 diabetes, the pancreas completely stops producing any insulin, a hormone that enables the body to use glucose. Type 2 diabetes results when the body doesn't produce enough insulin and/or is unable to use insulin properly.

In addition to the millions of people in this country who have been diagnosed with diabetes or who have it but don't yet know that they do, an estimated 41 million people ages 40 to 74 have entered the danger zone known as prediabetes. Their blood glucose levels are higher than normal but have not yet risen to the level at which they would indicate a diagnosis of diabetes. In people with prediabetes, the pancreas may not be working as efficiently as it once did or the body may be gradually building a resistance to the insulin it produces so that the hormone can't do as good a job of clearing glucose from the bloodstream.

Many Americans have prediabetes without knowing it. They are at high risk of developing type 2 diabetes and also are at increased risk of developing heart disease. For more on prediabetes:

  • Who is at risk of prediabetes?
  • Are children ever diagnosed with prediabetes?
  • What are the symptoms?
  • How is prediabetes diagnosed?
  • How great are the chances that someone with prediabetes will get diabetes?
  • How can prediabetes be prevented?
  • What dietary changes should I make?
  • Why is physical activity important?
  • If I've got prediabetes, can I get back to normal?
  • Who is at risk of prediabetes?

    Those who should be regularly screened (every one to two years) for prediabetes include overweight adults age 45 and older and those under age 45 who are overweight and who have one or more of the following risk factors:

    • They are habitually physically inactive.
    • They have previously been identified as having blood glucose levels that are above normal.
    • They have a family history of diabetes.
    • They are members of certain ethnic populations at heightened risk of diabetes (including Asian Americans, African-Americans, Latinos, and American Indians).
    • They have had gestational diabetes (diabetes during pregnancy) or have given birth to a child weighing more than 9 pounds.
    • They have elevated blood pressure.
    • They have an HDL cholesterol level (the "good" cholesterol) of 35 mg/dl or lower and/or a triglyceride level of 250 mg/dl or higher.
    • They have polycystic ovary syndrome.
    • They have a history of vascular disease.
    • They have any signs of insulin resistance, including acanthosis nigricans (velvety brownish-gray skin patches that are often on the neck or in skin folds).
    • Are children ever diagnosed with prediabetes?

      Prediabetes usually occurs in adults who are middle-aged or older. But a worrisome increase in the number of children and teenagers who are overweight has led to an upswing in the condition among younger people. Children who are overweight and have two of the following risk factors should be screened:

      • They have a family history of type 2 diabetes.
      • They are a member of a high-risk ethnic population (including Asian Americans, African-Americans, Latinos, and American Indians).
      • They show signs of insulin resistance, including acanthosis nigricans (velvety brownish-gray skin patches that are often on the neck or in skin folds).
      • The American Diabetes Association recommends that such high-risk children be screened beginning at age 10 or at the onset of puberty. If the test is normal, they should be screened again in two years.

        What are the symptoms of prediabetes?

        People with prediabetes often have no discernible symptoms, unlike people diagnosed with diabetes. (The classic symptoms of diabetes include frequent urination and excessive thirst, lack of energy, weight loss, constant hunger, and blurred vision.) So it's important to follow the screening guidelines for people at risk.

        How is prediabetes diagnosed?

        Two tests are generally used to diagnose prediabetes:

        In a fasting glucose test, a sample of your blood is drawn after you have fasted for eight to 12 hours. Your blood glucose is measured to see whether it is above the normal range (below 100 mg/dl). Prediabetes is diagnosed if your fasting glucose level is between 100 and 125 mg/dl; if so, you are said to have impaired fasting glucose (IFG). If the fasting blood glucose level rises to 126 mg/dl or above, you have diabetes.

        In the oral glucose tolerance test, blood tests are done after you have fasted for eight to 12 hours and consumed a sugar-filled liquid. Normally, blood glucose rises no higher than 140 mg/dl two hours after the drink. In people with prediabetes, the two-hour blood glucose is between 140 and 199 mg/dl; if you fall in this range,you have impaired glucose tolerance (IGT). If the two-hour blood glucose rises to 200 mg/dl or above, the diagnosis is diabetes.

        Both IFG and IGT are medical terms for prediabetes. If you have prediabetes, you should be tested every one to two years to make sure you are not developing diabetes.

        People with so-called metabolic syndrome are also considered to have prediabetes. Metabolic syndrome is a condition in which one has several problems at once: obesity, insulin resistance, high blood pressure, and abnormal cholesterol and triglyceride levels.

        How great are the chances that someone with prediabetes will get diabetes?

        Studies show that most people with prediabetes will develop type 2 diabetes within 10 years if they don't make some lifestyle changes. They also have a higher risk of developing cardiovascular disease.

        The risk of getting diabetes rises as people become more overweight and more sedentary. The risk is also higher in people who have a stronger family history of diabetes or who belong to an at-risk racial or ethnic minority group.

        How can prediabetes be prevented?

        The best way to prevent both prediabetes and diabetes is to stay as close as possible to your ideal weight through a combination of a healthy diet and physical activity. Increasing physical activity not only helps keep the weight down but also lowers blood glucose.

        Results of a large U.S. nationwide study released in August 2001, the Diabetes Prevention Program study, showed that participants at risk for developing type 2 diabetes were able to reduce the risk of developing diabetes over a three-year period by 58 percent through sustained modest weight loss and moderate-intensity physical activity, such as walking 30 minutes a day. The lifestyle intervention measures of the program had these goals:

        • help each patient achieve and maintain a weight loss of 7 percent with healthy eating and increased physical activity
        • help each patient get at least 150 minutes a week of moderate physical activity, such as walking or biking.
        • Participants were asked to lower fat intake to less than 25 percent of calories. If reducing fat did not result in weight loss, a calorie goal was added. Participants received training in diet, exercise, self-monitoring, goal-setting, and problem-solving. Interestingly, certain groups of DPP participants benefited more from the lifestyle intervention than other groups. For example, the lifestyle intervention worked particularly well in people ages 60 and older, reducing their development of diabetes by 71 percent.

          Participants were asked to lower fat intake to less than 25 percent of calories. If reducing fat did not result in weight loss, a calorie goal was added. Participants received training in diet, exercise, self-monitoring, goal-setting, and problem-solving. Interestingly, certain groups of DPP participants benefited more from the lifestyle intervention than other groups. For example, the lifestyle intervention worked particularly well in people ages 60 and older, reducing their development of diabetes by 71 percent.

          What dietary changes should I make?

          Having prediabetes does not mean that you can't eat certain foods. The solution isn't to avoid foods with sugar in them but to maintain your ideal weight. If you are overweight, your first and foremost goal should be to lose weight. This may mean working with a dietitian to determine the quantity and type of food you should eat at each meal. One of the key issues in losing weight is controlling portion size. Your dietitian will also direct you how to make food choices that cut down on the amount of fat you eat because each gram of fat has significantly more calories in it than a gram of carbohydrate or protein. This means:

          • eating more foods that are broiled and fewer foods that are fried
          • cutting back on the amount of butter you use in cooking or using margarine and olive oil instead of butter
          • eating fish and chicken more and only lean cuts of beef
          • eating more meatless meals, or reorienting your meals so that your dinner plate has more vegetables, fruit, and starches on it and less meat
          • Your dietitian will show you how you can continue to eat all the foods you love—probably just not in the same proportions as you have in the past.

            Why is physical activity important?

            Along with weight loss, your goal will be to begin a program of regular physical activity, if you aren't getting regular exercise now. Why? Because even moderate physical activity—a 30-minute walk most days, for example—will help you use the insulin you produce to convert food into energy. This will help keep your blood glucose lower. If you have a small piece of cake with a meal, follow it up with a brisk walk.

            If I've got prediabetes, can I get back to normal?

            Having prediabetes does not mean you will necessarily develop type 2 diabetes. And prediabetes can be reversed through such lifestyle changes as improved eating habits and regular physical activity. Follow the guidelines on preventing prediabetes and diabetes.

            Last reviewed on 10/27/08

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