Diabetes is a disease in which the body is unable to use glucose properly. Glucose is a simple sugar that gives the body's cells the energy they need to do their work. It is released from many of the foods we eat during the process of digestion.
Good health depends on the cells' ability to do their work. How well the cells perform depends on the answers to the following questions:
- Is there a normal level of glucose in the bloodstream?
- Are the cells able to draw in (absorb) glucose so it can be used as a source of energy?
In diabetes, the answer to one or both questions is "No."
- About 515,000 to 520,000 new cases of diabetes are diagnosed each year in the United States.
- There are three major types of diabetes.
- More people develop diabetes after age 40 than in their younger years.
- Those who become diabetic during middle age are often overweight.
THE PANCREAS IS IN CHARGE
The pancreas is the gland responsible for manufacturing and releasing chemicals, or hormones, that control the level of glucose in the blood. The pancreas lies behind the stomach and is shaped like a lamb chop. It contains two types of cells:
- The beta cells produce the hormone insulin, which lowers the blood glucose level.
- The alpha cells produce the hormone glucagon, which raises the blood glucose level.
INSULIN IS THE KEY
Insulin normally balances the cells' need for glucose by regulating the glucose level in the bloodstream. The carbohydrates we eat are the body's main source of glucose. After the carbohydrates are digested, insulin determines how much glucose is sent to the bloodstream, and how much is sent for storage in the liver and muscles.
Even when there is a normal glucose level in the bloodstream, the cells cannot absorb it without the help of insulin. Insulin attaches to the surface of the cells, and just as a key unlocks a door, insulin "unlocks" the cells' surface, allowing glucose to enter.
In people who have diabetes, either the pancreas stops producing insulin, or the insulin that is produced is less effective than normal. Each of these problems is linked to a specific type of diabetes.
TYPES OF DIABETES
There are three main types of diabetes - type 1, type 2, and gestational.
In type 1 diabetes, the beta cells stop producing insulin. In the past, this was also referred to as insulin-dependent diabetes, or IDDM. About 15,000 to 20,000 new cases of type 1 diabetes are diagnosed each year in the United States. Type 1 diabetes is about 1.5 to 2.0 times more common among whites than blacks.
In type 2 diabetes, the beta cells produce insulin, but the insulin is at a lower level or less effective than normal. As a result, the blood glucose level is frequently above normal range. In the past, this was referred to as non-insulin dependent diabetes, or NIDDM. The incidence of new cases of type 2 diabetes each year in the United States is 500,000. Type 2 diabetes is thought to affect more than 18% of older people. At all ages, the incidence is higher in African Americans, Mexican Americans, and Native Americans than in other groups.
Gestational diabetes occurs during pregnancy, often during the 24th to 30th week of pregnancy. Unlike type 1 and type 2 diabetes, gestational diabetes is a temporary condition. It only lasts until the pregnancy is completed. However, women who have gestational. diabetes are more likely than others to develop type 2 diabetes within the following 10 years. Roughly 50,000 pregnant women in the United States have gestational diabetes each year.
TYPE KEY POINTS
- Usually diagnosed in children or young adults.
- Symptoms may include unusual thirst, big appetite, frequent urination, blurred vision, and tiredness.
- Diagnosis frequently based on high blood glucose and the symptoms.
- Must be treated with Insulin.
- Usually diagnosed in people over age 40, and they are often overweight.
- May cause no symptoms at all or milder forms of the symptoms seen in individuals with type I diabetes.
- May be suspected when a routine blood test shows a high glucose level.
- Diagnosis often based on a fasting blood glucose test or an oral glucose tolerance test.
- Does not always require drug treatment.
- Occurs during pregnancy, usually during the 24th to 30th weeks.
- Often causes no symptoms or just tiredness.
- Diagnosis usually based on an oral glucose tolerance test.
- The diabetes disappears after the pregnancy is completed.
- Signals a risk for developing type 2 diabetes within 10 years.
SYMPTOMS AND DIAGNOSIS
What Are the Key Symptoms of the Most Common Types of Diabetes?
Type 1 diabetes tends to cause symptoms rather suddenly, and it most often affects children or young adults. Unusual thirst, increased appetite, frequent urination, blurred vision, and tiredness are all common signs of type 1 diabetes.
Type 2 diabetes usually evolves more slowly than type 1 - over months or sometimes years. It tends to be more common among overweight people over the age of 40. Some people with type 2 diabetes have milder forms of the symptoms described for type I diabetes, but many have no symptoms at all. Instead, their disease is discovered during a routine blood test or medical evaluation.
Gestational diabetes is only rarely accompanied by symptoms. Therefore, periodic blood glucose testing is very important during the 24th to 30th weeks of pregnancy.
How Is the Diagnosis Made?
Type 1 diabetes is diagnosed by measuring the blood glucose level. A high blood glucose reading, combined with the expected symptoms, is usually all that is needed to be sure of the diagnosis.
Type 2 diabetes may not be suspected until a routine blood test finds an unusually high glucose level. If type 2 diabetes seems like a possibility, a "fasting" blood glucose test is usually done. The word "fasting" is used because the blood sample is taken first thing in the morning or at least several hours after the person being tested has eaten. An oral glucose tolerance test is another choice. For this test, the person is given a drink that contains sugar, and his or her blood glucose level is measured after 30 minutes, 60 minutes, and 120 minutes to see how well the body handles sugar.
Gestational diabetes is usually identified with oral glucose tolerance testing. The test is done periodically during pregnancy.