Diabetes can result either from problems in the beta cells that produce and release insulin, or from the way insulin works on the storage tissues. Each of these problems leads to different types of diabetes. It is important for you and your doctor to know what type of diabetes you have so that you receive the appropriate treatment.
The most common type of diabetes, type 2 or adult-onset diabetes, starts in adulthood, typically after the age of 30. About 75 percent of all diabetics have type 2 diabetes. A common disease, it occurs in at least 10 percent of the U.S. population. Some 20 percent of people over the age of 60 have it. Type 2 diabetes frequently runs in families, so there is an important inherited tendency to develop this disease.
People with type 2 diabetes have two major problems with the way their bodies handle nutrients. First, the liver, muscles and fat cells are resistant to the effects of insulin. Thus, the storage tissues do not respond well to insulin produced in response to a meal. Secondly, patients with type 2 diabetes tend, over time, to make less and less insulin. Both problems lead to the buildup of glucose and other nutrients in the blood, which eventually results in tissue damage. Fortunately, most patients with type 2 diabetes continue to produce some insulin for many years and can take advantage of many treatment options available to increase the release of insulin from the pancreas and to make the tissues more sensitive to the insulin signal. When these treatments are successful, the need for insulin injections can be avoided.
About 8 of 10 patients with diabetes are overweight. In these individuals, obesity is an important contributor to their disease since we know that the tissues of overweight individuals become resistant to the effects of insulin. This is why diet and weight management are so important in the treatment of type 2 diabetes. In some individuals, diabetes can literally disappear if they lose enough weight.
Patients with type 2 diabetes usually develop the disease slowly as their weight increases. In fact, they usually have had the disease for many years before being diagnosed. In a large study recently conducted in England, 25 percent of patients with type 2 diabetes had the disease for 5 years or more before seeing a doctor about their symptoms.
It can occur later in life, but it is rare. Because of the severe insulin deficiency, many of the medications used to treat type 2 diabetics do not work for patients with type 1 diabetes. Rather, patients with type 1 diabetes must take insulin injections. Without the injections they quickly become severely ill and can die. These people often lose weight when they first develop the disease, or if their diabetes is poorly controlled. This is because the lack of insulin makes it impossible to store any nutrients, and as a result, the patient becomes very thin and weak. Type 1 diabetes usually does not run in families. Because of this, testing family members for diabetes is not recommended unless symptoms are present, or family members are participating in research studies.
Another common form of diabetes, gestational diabetes, develops during pregnancy. When a woman is pregnant, many changes occur in her body that result in an increased need for insulin. If the pancreas cannot respond to this challenge and increase its insulin production, then diabetes occurs. This usually occurs in the second half of the pregnancy, and usually goes away after the baby is born. However, as many as 8 of 10 women will become diabetic again with a subsequent pregnancy. Furthermore, a third of all women who experience gestational diabetes will go on to develop type 2 diabetes later in life, usually within 5 or 6 years of their pregnancy.
At one time, physicians told their patients that they had “borderline diabetes” if their blood glucose was higher than normal, but not high enough to be diagnosed as diabetes. This condition is now called impaired glucose tolerance. About 1 of every 4 patients with impaired glucose tolerance will eventually develop type 2 diabetes.