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type 2 diabetes mellitus

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Alternative Names
noninsulin dependent diabetes mellitus, adult-onset diabetes mellitus, NIDDM

Definition

Diabetes mellitus (more simply, "diabetes") comes in two types (1 and 2) which really are very different diseases, called by the same name only because both feature abnormally high blood sugar and its consequences. Type 2 is the more common of the two diseases.

Insulin is the hormone responsible for helping glucose (sugar) move into the cells so that the body can use it for fuel. Thus, insulin helps control the level of glucose in the blood. In type 2 diabetes, the person may make normal or even high levels of insulin, but the body cells do not use insulin effectively. This resistance to insulin is often caused by obesity..When the cells cannot take up glucose easily, they come up short on the energy they need to do their work.

What is going on in the body?

The pancreas, a long, thin organ located behind the stomach, makes insulin. In healthy people, the pancreas makes extra insulin when a person eats. Insulin moves glucose from the bloodstream into the body cells. The cells use glucose as their main energy source.

In a person with type 2 diabetes, even though the pancreas may make enough insulin, the body cells are resistant to its effects. Therefore, they do not receive enough glucose and the blood glucose level rises too high. This condition, known as hyperglycemia, causes damage to the body if left untreated.

What are the signs and symptoms of the disease?

Symptoms of type 2 diabetes usually develop slowly over time and are less noticeable as in type 1 diabetes. Many people with type 2 diabetes never have symptoms at all. If they do develop symptoms, they are usually the result of high levels of glucose in the blood and can include: Diabetic ketoacidosis sometimes occurs in people with type 2 diabetes. When the cells in the body don't get enough glucose, the body starts to burn fat for energy. This produces waste products known as ketones. High levels of ketones can result in too much acid in the body, called ketoacidosis. This condition requires medical attention right away to prevent coma and death. The symptoms and signs of ketoacidosis it can cause include:

What are the causes and risks of the disease?

Obesity is the most common cause of type 2 diabetes in both adults and children. A recent study showed a 33% increase in the number of Americans with type 2 diabetes during the past 8 years. The increase was 70% in people who were 30 to 39 years of age.

Type 2 diabetes is roughly ten times more common than type 1 overall in the US. Type 2 diabetes used to be rare in children, but is now diagnosed in 20% of the children who have diabetes. Of the children diagnosed with type 2 diabetes, 85% are obese. At this time, most children diagnosed with type 2 diabetes are 10 years of age or older. Researchers believe there will be an increase in type 2 diabetes in younger children who become obese.

Type 2 diabetes is more common in people with a family history of the disease. It's also more common among African Americans, Hispanic Americans, Pacific Islanders, Asian Americans, and Native Americans than among non-Hispanic whites.

Other risk factors for the development of type 2 diabetes include:

A recent study of 16,000 American women between the ages of 40 and 65 years showed that diabetes was listed as one of the top six diagnoses. A long-term study is under way to see if menopause and changes in hormone levels are factors in developing type 2 diabetes.

Almost all people who develop type 2 diabetes have a condition called prediabetes first. This condition used to be known as impaired glucose tolerance or impaired fasting glucose, and the ADA estimates that almost 16 million people over the age of 40 have it. This condition occurs when blood glucose levels are higher than healthy levels but too low to be diagnosed as diabetes. Without lifestyle changes, most people who have prediabetes will progress to type 2 diabetes within 10 years.

What can be done to prevent the disease?

The best way to prevent type 2 diabetes is through modest lifestyle changes. These changes can be helpful to almost any person's health, but if a person has been diagnosed with prediabetes, lifestyle changes are essential. The key is to:

The Disease Prevention Program, a federally funded study, demonstrated the effect of lifestyle changes on a person's risk factors for type 2 diabetes. Participants in the study exercised moderately for 150 minutes a week. Most of them chose to walk briskly for 30 minutes, 5 days a week. They also ate a reduced-fat diet with large amounts of vegetables. The weight loss goal was 7%, or 14 pounds for a person weighing 200 pounds. With these changes, the individuals lowered their risk of developing type 2 diabetes by 58%.

How is the disease diagnosed?

A doctor may suspect diabetes after taking a person's health history and doing a physical exam. Based on those results, the doctor may want to check for a high glucose level in the blood. There are several types of blood tests doctors can use to diagnose diabetes, including:

What are the long-term effects of the disease?

Over time, high blood sugar levels damage blood vessels, nerves, and other internal structures. Long-term effects of diabetes may include:

Coma or death may occur as a result of diabetic ketoacidosis. In addition, smoking greatly increases the risk of getting many of these long-term effects. People with diabetes who smoke are a much higher risk for heart attacks, strokes, infections, and poor circulation.

What are the risks to others?

Type 2 diabetes is not catching and poses no risk to others. It does tend to run in families.

What are the treatments for the disease?

The most effective treatment for type 2 diabetes is a change in lifestyle, including the following:

A person with type 2 diabetes may also be treated with oral medicines and/or insulin shots. Diabetes pills can work in four ways.

Careful monitoring and management help keep diabetes under control and reduce the risk of long-term effects. A person with diabetes should:

Treating the complications of diabetes may involve many different specialists. For example, a person with diabetes may need to see eye, heart, foot, hormone, and circulation specialists. Dieticians also help people with diabetes by designing a healthy eating plan. Dieticians can also suggest healthy calorie intake levels and types of foods to eat.

What are the side effects of the treatments?

The oral medicines used for type 2 diabetes may cause weight gain, diarrhea, gas, allergic reactions, or liver damage. Some may also cause blood sugar levels to go too low. This condition is known as hypoglycemia. It can cause:

If this condition goes untreated, a person can pass out. The usual treatment for low blood glucose is to drink a sweet beverage or eat a sweet food. If low blood glucose goes untreated, a person may pass out or have seizures. Emergency medical care is crucial in this situation.

What happens after treatment for the disease?

Although type 2 diabetes cannot be cured, it can be controlled with careful management. The person will need lifelong monitoring and treatment to help prevent serious complications.

How is the disease monitored?

A person with diabetes should keep all of appointments with his or her primary doctor, as well as other scheduled specialists. Physical exams, blood tests, urine tests, foot and skin care, routine eye exams, and routine dental care are all part of basic care for a person with diabetes.

The main goal of treatment is to keep blood sugar levels as close to a healthy range as is safely possible. In general, ideal ranges of blood sugar levels are 80 to 120 milligrams per deciliter (mg/dL) before meals and 100 to 140 mg/dL at bedtime. Any new or worsening symptoms should be reported to the healthcare provider.


Author:Eileen McLaughlin, RN, BSN
Date Written:06/22/00
Medical Review:Curtis Harris, MD
Date Written:9/19/2006
Reviewer:Reginald Finger, MD
Date Reviewed:9/25/2006
Contributors
Potential conflict of interest information for reviewers available on request