Diabetes was known in ancient times and remains today a world-wide and increasing health problem.  One of the leading causes of death and disability in the United States, diabetes is a life-long disease that currently affects about 18 million Americans (6%).  "While an estimated 13 million have been diagnosed with diabetes, unfortunately, 5.2 million people (or nearly one-third) are unaware that they have the disease."(1)

Diabetes is associated with long-term complications that affect almost every part of the body. The disease often leads to blindness, heart and blood vessel disease, stroke, kidney failure, amputations, and nerve damage. Uncontrolled diabetes can complicate pregnancy, and birth defects are more common in babies born to women with diabetes.

Diabetes is a disorder of metabolism--the way our bodies use digested food for growth and energy. Most of the food we eat is broken down into glucose, the main source of fuel for the body. After digestion, glucose is absorbed into the bloodstream, where it is transported to all the cells of the body to be used for growth and energy. However, in order for glucose to pass into the cells, insulin must also be present in the blood stream. Insulin is a hormone produced by the pancreas, a large gland behind the stomach.

The pancreas is a gland in the abdomen behind the stomach. It produces enzymes that are released into the small intestine to help with digestion. (The duodenum is the first part of the small intestine.) The pancreas also contains clusters of cells called islets. The cells in these islets produce hormones such as insulin and glucagon, which help control the level of glucose (a type of sugar) in the blood.

During and after a meal, the pancreas automatically produces the right amount of insulin that is needed to transport the ingested glucose from the blood into the cells. In people with diabetes, however, the pancreas either produces too little or no insulin at all, or the cells do not respond appropriately to the insulin that is produced. As a result, the glucose builds up in the blood stream instead of being transported into the cells to be used for fuel.  Eventually high levels of  blood glucose will overflow into the urine, and be eliminated out of the body. Thus, the body loses its main source of fuel even though the blood contains large amounts of glucose. Illustration courtesy of the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health

There are three major types of diabetes:

1) Type 1 diabetes is an autoimmune disease and starts most often in children and young adults.  An autoimmune disease results when the body's system for fighting infection (the immune system) turns against a part of the body. In diabetes, the immune system attacks the insulin-producing beta cells in the pancreas and destroys them. The pancreas then produces little or no insulin. As a result, daily injections of insulin are required to sustain life. Symptoms of type 1 diabetes usually develop over a short period, although beta cell destruction can begin years earlier. Symptoms include increased thirst and urination, constant hunger, weight loss, blurred vision, and extreme fatigue. If not diagnosed and treated with insulin, a person with type 1 diabetes can lapse into a life-threatening diabetic coma, also known as diabetic ketoacidosis.

2) Type 2 diabetes is far more common than type 1 and makes up 90% or more of all cases. Type 2 diabetes usually occurs in adulthood although it is increasingly being diagnosed in children and adolescents who are obese and inactive. Type 2 diabetes is a lifestyle disease with the prevalence increasing markedly with age, obesity and physical inactivity.   Heredity strongly influences most diabetes.   In Type 2, the pancreas still makes insulin but it's an inadequate amount for the body's needs.  Also, in Type 2, the cells of the body are resistant to the effects of insulin.   The symptoms of type 2 diabetes develop gradually. Their onset is not as sudden as in Type 1. Symptoms may include fatigue or nausea, frequent urination, unusual thirst, weight loss, blurred vision, frequent infections, and slow healing of wounds or sores. Some people have no symptoms.  

3) Gestational diabetes affects about 4% of all pregnant women (3) and develops at any time during pregnancy in a person who does not have diabetes.  During pregnancy, increased levels of estrogen and placental hormones antagonize insulin.  Like type 2 diabetes, gestational diabetes  occurs more often in African Americans, American Indians, Hispanic Americans, and among women with a family history of diabetes. Women who have had gestational diabetes have a 20 to 50 percent chance of developing type 2 diabetes within 5 to 10 years.

1. Impaired Fasting Glucose (IFG) A person has impaired fasting glucose (IFG) when fasting plasma glucose is 100 to 125 mg/dL. This level is higher than normal but less than the level indicating a diagnosis of diabetes.
    
2. Impaired Glucose Tolerance (IGT) Impaired glucose tolerance (IGT) means that blood glucose during the oral glucose tolerance test (OGTT) is higher than normal but not high enough for a diagnosis of diabetes. IGT is diagnosed when the glucose level is 140 to 199 mg/dL 2 hours after a person drinks a liquid containing 75 grams of glucose.

 *These recent estimates were calculated using data from the 1988-1994 National Health and Nutrition Examination Survey and projected to the 2000 U.S. population.

In order to determine whether or not a patient has pre-diabetes or diabetes, health care providers will draw blood to measure either a Fasting Plasma Glucose Test (FPG) or an Oral Glucose Tolerance Test (OGTT). Either test can be used to diagnose pre-diabetes or diabetes. The American Diabetes Association recommends the FPG because it is easier, faster, and less expensive to perform.

• With the Fasting Plasma Glucose Test (FPG), a fasting blood glucose level between 100 and 125 mg/dl signals pre-diabetes. A person with a fasting blood glucose level of 126 mg/dl or higher has diabetes.

• In the Oral Glucose Tolerance Test (OGTT), a person's blood glucose level is measured after a fast and two hours after drinking a glucose-rich beverage. If the two-hour blood glucose level is between 140 and 199 mg/dl, the person tested has pre-diabetes. If the two-hour blood glucose level is at 200 mg/dl or higher, the person tested has diabetes.(1)
   

Gestational diabetes is diagnosed based on plasma glucose values measured during the OGTT. Glucose levels are normally lower during pregnancy, so the threshold values for diagnosis of diabetes in pregnancy are lower. If a woman has two plasma glucose values meeting or exceeding any of the following numbers, she has gestational diabetes: a fasting plasma glucose level of 95 mg/dL, a 1-hour level of 180 mg/dL, a 2-hour level of 155 mg/dL, or a 3-hour level of 140 mg/dL.

There are two different tests to assess your long-term overall blood glucose control:

1) The A1C test, which used to be called hemoglobin A-1-C, is a one-time blood test that reflects your average blood glucose level over the last 3 months. It is the best way to know your overall blood glucose control during this period of time.  This test is drawn at your doctor's office or by a home health nurse.

2) Blood glucose testing  measures your exact blood glucose at the time you check it.  This is done by obtaining a very small drop of blood with a finger-stick mechanism,  and reading the results with a small portable meter. (see illustration right, image courtesy of Nat'l Institute of Diabetes and Digestive and Kidney Diseases, Nat'l Institutes of Health) People with diabetes need to perform this test on a regular basis at home and keep a log of the results.  The frequency that its needed varies considerably depending on the patients condition and medications. Read important facts about Blood Glucose Meters from the FDA.

• Diabetes: Introduction, Eye Complications, Foot Care, and Meal Planning from Medline Plus, a service of the National Institute of Health and National Library of Medicine.  These are excellent video tutorials that are well-illustrated and easy to understand.  Click on the above link and scroll down to "Diabetes" on the opening page.

1. Diabetes Basics from the American Diabetes Association.
2. Patient Education Handouts from the National Institute of Health.  This is an extensive list of well-illustrated and easy-to-understand patient education handouts for people with Diabetes I and II
3. Diabetes from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
4. "Diabetes and its Management", 6th Edition, by Watkins, Amiel, Howell, and Turner, Blackwell Publishing, 2003
5. Insulin Pumps from the American Diabetes Association
6. Diabetes Risk Test   Take the Diabetes Risk Test from the American Diabetes Association and find out if you are at high risk for developing Type 2 diabetes.
7. Blood Glucose Meters from the FDA
8. Juvenile Diabetes Research Foundation, 5959 Central Avenue, Suite 202, St. Petersburg, FL 33710
   Phone (727) 344-2873
9. Find a specialist: American Association of Clinical Endocrinologists AACE Physician Finder
Diabetes Control and Complications Trial by the National Institute of Diabetes and Digestive and Kidney Disease