Diabetes

What is diabetes?

Diabetes is a complex medical condition that results from either a deficiency of insulin or a decreased ability of the body to use insulin (insulin resistance). Insulin is a hormone that allows glucose to enter cells and be converted to energy. Insulin is also needed to synthesize protein and store fats. In uncontrolled diabetes, glucose and lipids remain in the blood, resulting in hyperglycemia, or high blood sugar. Diabetics are at increased risk for severe health complications affecting vital organs such as the eyes, nerves, kidneys and cardiovascular system. For example, diabetes is the leading cause of end-stage renal disease, blindness and amputation, and a major cause of cardiovascular disease and premature death in the general population.

How many people have diabetes?

According to the American Diabetes Association, there are 18.2 million people in the United States – or 6.3 percent of the population – who have diabetes. An estimated 13 million have been diagnosed, but 5.2 million people are unaware that they have the disease. Diabetes is the sixth leading cause of death in the United States, contributing to more than 213,000 deaths annually. Morbidity and mortality due to diabetes has made this disease a significant public health problem and led the Centers for Disease Control and Prevention to recently declare the disease an epidemic in the United States.

What causes diabetes?

There are two main types of diabetes. Type 1 diabetes is a chronic autoimmune disease. It is characterized by complete insulin deficiency due to the destruction of cells within the pancreas that produce insulin. Type 1 diabetes accounts for 5 percent to 10 percent of cases and is a common metabolic disorder in children, typically occurring in childhood or in the teenage years. Research indicates that both environmental (e.g., viral infection, nutrition) and genetic factors influence susceptibility to type 1 diabetes.

Type 2 diabetes is another form of the disease that is characterized by insulin resistance, a condition in which the body produces enough insulin but is not able to respond to it. As the need for insulin rises, the pancreas gradually loses its ability to produce the hormone. Usually affecting people over the age of 40 who are overweight and lead a sedentary lifestyle, type 2 diabetes is far more common than type 1, accounting for 90 percent to 95 percent of all cases.

Can diabetes be prevented?

Research studies have found that lifestyle changes can prevent or delay the onset of type 2 diabetes among high risk adults such as people with impaired glucose tolerance. Lifestyle interventions included diet and moderate-intensity physical activity. For both sexes and all age, racial and ethnic groups, the development of diabetes was reduced 40 percent to 60 percent during these studies.

Research has also shown that medications have been successful in preventing diabetes in some population groups. In the Diabetes Prevention Program, a large prevention study of people at high risk for diabetes, people treated with the drug metformin reduced their risk of developing diabetes by 31 percent. Treatment with metformin was most effective among people who were younger (25 to 40 years of age) and heavier (50 to 80 pounds overweight). Among older people and people who were not as overweight, the treatment was not as effective.

Currently, there are no known methods to prevent type 1 diabetes.

What are the symptoms of diabetes?

Some symptoms of diabetes include:

• Frequent urination
• Excessive thirst
• Unexplained weight loss
• Extreme hunger
• Sudden vision changes
• Tingling or numbness in hands or feet
• Feeling very tired much of the time
• Very dry skin
• Sores that are slow to heal
• More infections than usual

Nausea, vomiting or stomach pains may accompany some of these symptoms in the abrupt onset of type 1 diabetes.

What are some of the complications of diabetes?

Many of the complications of diabetes are strongly related to high blood sugar levels. It is believed that keeping blood sugar levels within target range is the best defense against the complications of diabetes. Some of the complications of diabetes are described below.

Heart Disease

Cardiovascular disease is the leading cause of diabetes-related deaths. Adults with diabetes have heart disease death rates that are two to four times higher than those of adults without diabetes.

Stroke

The risk for stroke is also two to four times higher among people with diabetes.

High Blood Pressure

About 73 percent of adults with diabetes have high blood pressure (130/80 mm Hg or higher) or use prescription medications for hypertension.

Blindness

Diabetes is the leading cause of new cases of blindness among adults between the ages of 20 to 74.

Retinopathy

Diabetic retinopathy (any of various noninflammatory disorders of the retina) causes between 12,000 to 24,000 new cases of blindness each year.

Kidney Disease

Diabetes is the leading cause of treated end-stage renal disease, accounting for 43 percent of new cases.

Nervous System Damage

About 60 percent to 70 percent of people with diabetes have mild to severe forms of nervous system damage. The results of such damage include impaired sensation or pain in the feet or hands, slowed digestion of food in the stomach, carpal tunnel syndrome, and other nerve problems.

Amputations

More than 60 percent of nontraumatic lower-limb amputations in the United States occur among people with diabetes. Severe forms of diabetic nerve disease are a major contributing cause of lower-extremity amputations.

Pregnancy Complications

Diabetes can cause several pregnancy complications. Poorly controlled diabetes before conception and during the first trimester of pregnancy can cause major birth defects in 5 percent to 10 percent of pregnancies and spontaneous abortions in 15 percent to 20 percent of pregnancies. Poorly controlled diabetes during the second and third trimesters of pregnancy can result in excessively large babies, posing a risk to the mother and the child.

How is diabetes treated?

In order to survive, people with type 1 diabetes must have insulin delivered by injections or a pump. Many people with type 2 diabetes can control their blood glucose by following a careful diet and exercise program, losing excess weight and taking oral medication. Among adults with diagnosed diabetes, about 11 percent take both insulin and oral medications, 22 percent take insulin only, 49 percent take oral medications only, and 17 percent do not take either insulin or oral medications.

The growing health burden of diabetes has highlighted the importance of efficient disease management to prevent complications. Treatment is aimed at keeping blood glucose near normal levels at all times and includes diet control, exercise, blood glucose testing, oral medication and/or insulin injections. Moreover, current directions in diabetes research include pancreas and islet cell transplantation and gene therapy, as well as modulating the immune system to prevent the onset of the disease in individuals predicted to be at high risk.

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