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Unknown: Diabetes

Unknown: Diabetes

Causes and Symptoms
The Future
For more information


Diabetes melllitus, or DM, is a lifelong disorder in which the patient's body cannot regulate the levels of glucose (sugar) in the blood. The problem may be caused by too little insulin—a hormone produced by the pancreas that helps the body use the glucose properly—or the body's resistance to using the insulin that is secreted by the pancreas.

There are three major types of diabetes:

  • Type 1. Type 1 diabetes, which is sometimes called insulin-dependent diabetes because the patient must take a daily dose of insulin in order to live, is a disease in which the person's immune system attacks the cells in the pancreas that produce insulin. This type of diabetes usually develops over a short period of time, most often in children and young adults. It accounts for 5–10 percent of cases of diabetes diagnosed in the United States.
  • Type 2 diabetes. Type 2, sometimes called adult-onset diabetes, is the most common type, accounting for 90–95 percent of cases in North America. It usually develops relatively slowly and is associated with being overweight and a family history of diabetes. Most people with type 2 diabetes are resistant to insulin rather than having a pancreas that is not producing enough of the hormone.
  • Gestational diabetes. Some women develop a temporary form of diabetes toward the end of their pregnancy that goes away after the baby is born. Women with gestational diabetes have an increased risk of developing type 2 diabetes within five to ten years.

Doctors also consider a condition known as pre-diabetes or impaired glucose tolerance to be a health concern. People with this condition have a higher-than-normal blood glucose level but not high enough to meet the criteria for a diagnosis of diabetes. Many people with pre-diabetes will develop type 2 diabetes within ten years.


People with type 1 diabetes are likely to feel sick fairly suddenly. The most common symptoms are increased thirst, weight loss in spite of increased appetite, nausea and vomiting, and blurred vision. If the person is not diagnosed and treated with insulin quickly, they can fall into a coma and die.

People with type 2 diabetes may not have any noticeable symptoms for some years. When they do develop symptoms, they may feel thirsty and hungry, urinate more frequently, tire easily, have vision problems, or notice that wounds and sores heal slowly. Women with gestational diabetes may not have any symptoms at all.

Diabetes is a serious disease because it often leads to complications that seem far removed from digestive issues. People with diabetes are at increased risk of blood vessel injury, stroke, blindness, heart disease, kidney failure, gangrene leading to limb amputations, and nerve damage. Women with gestational diabetes are more likely to have babies with birth defects.


About 21 million people in the United States, or 7 percent of the population, have diabetes. Unfortunately, 6.5 million of these people have not been diagnosed with the disease. Between 54 and 57 million Americans were thought to have pre-diabetes as of 2007. Diabetes is the sixth leading cause of death in the United States; about 65 percent of deaths among patients with diabetes are the result of heart attacks and stroke, but diabetes is the underlying cause.

Diabetes is a major cause of disability and death in the United States. It costs the country about $135 billion each year, including $42 billion in indirect costs (disability payments, lost work time, and premature death) and $93 billion in direct medical costs (hospital admissions, medical care, and treatment supplies).

Dr. Banting's Breakthrough

Prior to the early 1920s, type 1 diabetes was not only incurable but fatal within a relatively short period of time. Although doctors were aware that the disease was caused by the lack of insulin secreted by the pancreas, early attempts to treat diabetics by feeding them fresh pancreas had failed. Frederick Banting (1891–1941), a Canadian doctor, worked together with a medical student named Charles Best at the University of Toronto to see whether they could successfully extract insulin from the pancreas and use it to treat diabetics. The two men first tested the extracted insulin on diabetic dogs. Their first human patient was a man named Leonard Thompson, who was close to death from diabetes. The success of Thompson's treatment led to Banting's winning the Nobel Prize in physiology or medicine in 1923.

The risk factors for type 1 and type 2 diabetes are different. People at increased risk of type 1 diabetes include:

  • Children and young adults rather than older adults
  • Caucasians, particularly people of Swedish or Finnish background Risk factors for type 2 diabetes include:
  • Family history of diabetes.
  • Personal history of gestational diabetes or pre-diabetes.
  • Age over forty-five.
  • Obesity. 80 percent of persons diagnosed with type 2 diabetes are overweight.
  • Ethnicity. African Americans, Hispanics, Native Americans, Pacific Islanders, and some Asian Americans are at greater risk than Caucasians. Native Americans have the highest rates of type 2 diabetes of all ethnic groups in the United States.
  • High blood pressure.
  • High blood cholesterol levels.
  • Not getting enough exercise. Exercise helps the body use blood sugar more efficiently.

Causes and Symptoms

The basic cause of type 1 diabetes is an insufficient supply of insulin from the pancreas caused by an autoimmune disorder. What triggers the immune system's attack on the patient's pancreas, however, is not yet known. In type 2 diabetes, the patient's pancreas is secreting insulin but the body is not using the hormone efficiently—a condition known as insulin resistance. In type 2 diabetes, there are increased levels of insulin in the blood as well as sugar.

The central symptoms of both type 1 and type 2 diabetes are:

  • Increased thirst
  • Increased urination
  • Increased appetite
  • Fatigue


The American Diabetes Association recommends that all adults over forty-five be screened for type 2 diabetes at least every three years, and that people with several risk factors be screened yearly.

Diabetes is diagnosed by the results of blood tests. There are several different types of blood tests that may be used.

  • Fingerstick. This type of test is often used as a screener in the doctor's office. The doctor pricks the patient's fingertip with a needle and touches a test strip attached to a small handheld glucometer to the drop of blood, which provides a blood sugar reading within a few seconds. This method is used by diabetic patients at home to monitor their blood sugar levels.
  • Fasting blood glucose test. The patient has blood drawn first thing in the morning after having eaten nothing since midnight of the previous night. A score over 126 milligrams per deciliter (mg/dL) indicates possible diabetes.
  • Glucose tolerance tests. In this test, the patient has blood drawn twice, the first time after fasting for eight hours and the second time two hours later, after drinking a very sweet drink. A score over 200 mg/dL suggests diabetes.
  • Hemoglobin A1c test. This test is used to monitor blood sugar control in people known to have diabetes. It measures the amount of blood sugar attached to the hemoglobin in red blood cells. If more than 7 percent of the hemoglobin has excess sugar attached to it, the person needs to get better control over their blood sugar levels.


There is no cure for diabetes. Treatment is based on a combination of diet and weight control; physical exercise; injected insulin or oral medications to reduce blood sugar levels; and home monitoring of blood glucose levels. The goal of treatment is to control blood sugar levels and to lower the patient's risk of blindness, frequent infections, heart disease, and other complications of diabetes:

  • Diet: Patients with type 2 diabetes usually need to lower their weight. In addition, they must learn to eat roughly the same size meals at the same times each day so that their insulin doses will not lower their blood sugar level too quickly or too far.
  • Exercise: Exercise reduces the patient's risk of leg ulcers, stroke, heart disease, kidney failure, and other complications of diabetes.
  • Insulin and oral medications: Patients with type 1 diabetes must use injected insulin. Type 2 diabetics can be treated with oral medications that increase the body's sensitivity to insulin, stimulate the pancreas to produce more insulin, or decrease the amount of glucose produced by the liver. They may need insulin injections in addition to these oral medications.
  • Home monitoring. Patients with either type of diabetes must check their blood sugar levels four times a day—before each meal and at bedtime—and keep a careful record of the test results.


The prognosis of diabetes depends on the type and the patient's willingness to take responsibility for their health. Patients who do not take their

insulin or other medications regularly or fail to monitor their blood sugar at home run the risk of severe complications.

According to the American Diabetes Association, people with diabetes are at risk for the following complications:

  • Diabetics are two to four times more likely to develop heart disease than those without diabetes.
  • Between 12,000 and 24,000 diabetics lose their eyesight each year.
  • About 48,000 diabetics develop end-stage kidney disease each year.
  • Around 71,000 amputations of legs and feet are performed each year in people with diabetes.
  • Thirty-five percent of people with diabetes have periodontal disease.
  • About 60–70 percent of diabetics have some degree of damage to the nervous system.


There is no way known to prevent type 1 diabetes, since its triggers are not yet understood.

People can prevent or lower their risk of type 2 diabetes by a combination of lifestyle changes and self-care:

  • Keeping one's weight at a healthy level and eating a low-fat, high-fiber diet.
  • Not smoking.
  • Getting regular exercise, at least 30 minutes of walking or other activity five days a week.
  • Keeping alcohol intake low.
  • Getting regular checkups for blood pressure and blood cholesterol levels, and taking any medications prescribed by the doctor.
  • If over forty-five, getting screened regularly for type 2 diabetes.

The Future

Diabetes is expected to be a growing public health problem in the developed countries in the future. One reason is the aging of the population; the highest rates of diabetes in the United States are in people over 60. Another reason is the rise in obesity among children as well as adults.

The Centers for Disease Control and Prevention (CDC) predicts that one in three Americans born in the year 2000 will eventually develop type 2 diabetes. By 2050, the CDC expects the rate of diabetes in the United States to increase by 165 percent over the figures for 2006.

SEE ALSO Childhood obesity; Gangrene; Heart attack; Hypertension; Hypoglycemia; Obesity; Periodontal disease; Stroke


Endocrinologist: A doctor who specializes in disorders of the pancreas and other glands.

Gestational: Pertaining to pregnancy.

Glucometer: A small blood testing device that can be used to screen for diabetes or used at home to monitor blood sugar levels.

Insulin: A hormone secreted by the pancreas that causes the cells in the liver, muscle and fatty tissues of the body to use the glucose carried in the bloodstream after a meal.

Pancreas: A small organ that lies between the stomach and the liver and secretes insulin.

For more information


American Diabetes Association. Complete Guide to Diabetes, 4th ed. New York: Bantam Books, 2006.

Brill, Marlene Targ. Diabetes. Minneapolis, MN: Twenty-First Century Books, 2008.

Parker, Katrina. Living with Diabetes. New York: Facts On File, 2008.


McDonald, Brent, and Gina Kolata. “Taking Diabetes to Heart.” New York Times, August 19, 2007. Available online at (accessed on September 21, 2008). This is a video about the relationship between diabetes and heart disease. It runs six and a half minutes.


American Diabetes Association. All about Diabetes. Available online at (accessed on September 21, 2008).

Centers for Disease Control and Prevention (CDC). The Eagle's Nest. Available online at (updated November 14, 2007; accessed on September 21, 2008). This teaches children about preventing and controlling diabetes. It is based on Native American traditions about the eagle as a wise bird and a messenger.

eMedicine Health. Diabetes. Available onine at (accessed on September 21, 2008).

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Diabetes Overview. Available online at (updated September 2006; accessed on September 21, 2008).

National Library of Medicine (NLM). Diabetes—Introduction. Available online at (accessed on September 21, 2008). This is an online tutorial with voiceover; viewers have the option of a self-playing version, an interactive version with questions, or a text version.

TeensHealth. Diabetes Basics. Available online at (updated September 2007; accessed on September 21, 2008).

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