Types of Diabetes

by Food and Drug Administration (FDA)

(Page 2 of 4)

Type 1 Diabetes

People with type 1 diabetes, such as 56-year-old Paul Keister of Arlington, Va., must inject replacement insulin to control the levels of glucose in their blood. Frequent tests (several times a day) using blood obtained from finger pricks are required to maintain good blood sugar control.

In type 1 diabetes, the beta cells of the pancreas are destroyed by the body's immune system, which is responsible for recognizing and destroying outside invaders such as viruses or bacteria.

In a process that is not well-understood, the body begins to think that its own pancreatic beta cells are "foreign" and sets off an "autoimmune" response that ends up destroying the cells. As a result, no insulin can be produced.

Type 1 diabetes accounts for 5 percent to 10 percent of all people with the disease. This type is sometimes called juvenile diabetes because it most commonly appears initially in children or adolescents. However, people older than 30 also may develop the condition.

Scientists believe that some environmental factor — possibly a viral infection or something related to nutrition — causes the immune system to destroy the insulin-producing cells. At 30 years old, Keister was diagnosed with type 1 diabetes following a stomach illness and after a stubborn tooth infection refused to go away.

The resulting insulin deficiency is usually severe. Without injections of enough insulin to control increases in the blood sugar, diabetic ketoacidosis (coma and potentially death) can result. Today, type 1 diabetes is treatable, and ketoacidosis preventable by taking sufficient amounts of insulin and by following dietary guidelines set by doctors and the ADA.

Type 2 Diabetes

Type 2 diabetes accounts for more than 90 percent of cases in the United States. In this type, the pancreas continues to produce insulin; however, the body develops resistance to its effects, resulting in a different kind of insulin deficiency than in type 1. Although the blood sugar rises in type 2 diabetes for different reasons than in type 1, the symptoms and potential complications are similar.

Certain racial and ethnic groups, including blacks, American Indians, Mexican-Americans and other Hispanics, are at increased risk for getting the disease. And obesity is a risk factor for type 2 diabetes. Although doctors don't know exactly why, they say it's clear that the muscle cells (where most of the sugar breakdown occurs) of obese people are far less responsive to insulin than are muscle cells of thinner people. An obese person's pancreas has to put out large amounts of insulin to keep blood sugars normal. The likelihood of developing type 2 diabetes in people who are at risk increases with age and weight gain.

The typical person with type 2 diabetes is older, overweight, and often has a family history of diabetes. Dale Driscoll of Frederick, Md., was diagnosed with type 2 diabetes at about the same age that Paul Keister was diagnosed with type 1 — an indication that age alone is not a reliable diagnostic criterion. And there is little evidence to suggest that diabetes runs in Driscoll's family.

It's important, says Saudek, to know that some people don't fit neatly into either of these diagnostic "boxes." Like Driscoll, none of Keister's relatives on either parent's side has ever had diabetes, even though type 1 occurs in people with a genetic susceptibility. There are exceptions to the general rule that diabetes occurring in the young is type 1, and that diabetes occurring in older people is type 2. Likewise, taking insulin does not mean you have type 1 diabetes, just as obesity is not a sure diagnostic sign of type 2.

Type 2 diabetes is nearing epidemic proportions in the United States, according to diabetes experts, due to an increased number of older Americans and a greater prevalence of obesity and sedentary lifestyles.

Gestational Diabetes

Between 3 percent and 5 percent of pregnant women in the United States develop gestational diabetes — elevated blood sugar due to certain hormones that occurs only during pregnancy. It is important to diagnose and treat gestational diabetes properly because it increases the risk of a baby growing larger than he or she would have been, and a large baby may have difficulty during delivery, or may be born by cesarean section.

Keeping blood sugar within a normal range during the pregnancy reduces these risks. Women who experience gestational diabetes have a greater risk of developing diabetes later in life. One large study found that more than half of women who had gestational diabetes eventually developed type 2 diabetes.

Controlling Diabetes — Treatment Goals

Daily monitoring and careful control of blood sugar levels are the most important steps that people with diabetes can take, says David G. Orloff, M.D., director of the FDA's division of metabolic and endocrine drugs. Over the past decade, "tight control" of blood sugar with a goal of achieving and maintaining near-normal levels has become the standard of care for both type 1 and type 2 diabetes. Maintaining normal levels is difficult, Orloff says, "but good glycemic control is key to preventing long-term complications." Another reason for good blood sugar control, Orloff adds, "is that it does make a difference in how people feel."

Joanna K. Zawadzki, M.D., of the FDA's metabolic and endocrine drugs division, cautions that "just having a blood glucose monitor is not adequate follow-up to your diabetic treatment." People need better blood sugar control than just enough to avoid symptoms, she says. Keeping blood sugars always between 150 mg/dL and 200 mg/dL, for instance, may help a person avoid obvious symptoms, but may not be good enough to avoid the long-term complications. "Diabetes treatment is a complex approach that comprises a team of professionals, the patient, his or her family, and treatment and goals agreed upon by the team." Zawadzki adds, "Work with your doctor to come up with reasonable expectations for your individual treatment plan."

People with type 1 diabetes need insulin from the time they are initially diagnosed, throughout life. Type 2 diabetes may often mean a prescribed regimen of diet and exercise in the initial phases of the disease. Frequently, however, and certainly over time, changes in diet and exercise aren't enough to keep blood sugar at near-normal levels. The next step for these people is taking a medicine that lowers the blood sugar. There are two basic kinds: insulin therapy and oral medications.

About the Author

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