Diabetes mellitus is a group of diseases characterized by high levels of blood glucose resulting from defects in insulin production, insulin action, or both. Diabetes can be associated with serious complications and premature death, but people with diabetes can take steps to control the disease and lower the risk of complications.
Types of diabetes
Type 1 diabetes was previously called insulin-dependent diabetes mellitus (IDDM) or juvenile-onset diabetes. Type 1 diabetes develops when the body’s immune system destroys pancreatic beta cells, the only cells in the body that make the hormone insulin that regulates blood glucose. This form of diabetes usually strikes children and young adults, who need several insulin injections a day or an insulin pump to survive. Type 1 diabetes may account for 5 percent to 10 percent of all diagnosed cases of diabetes. Risk factors for type 1 diabetes include autoimmune, genetic, and environmental factors.
Type 2 diabetes was previously called non-insulin-dependent diabetes mellitus (NIDDM) or adult-onset diabetes. Type 2 diabetes may account for about 90 to 95 percent of all diagnosed cases of diabetes. It usually begins as insulin resistance, a disorder in which the cells do not use insulin properly. As the need for insulin rises, the pancreas gradually loses its ability to produce insulin. Type 2 diabetes is associated with older age, obesity, family history of diabetes, prior history of gestational diabetes, impaired glucose tolerance, physical inactivity, and race/ethnicity. African Americans, Hispanic/Latino Americans, American Indians, and some Asian Americans and Pacific Islanders are at particularly high risk for type 2 diabetes. Type 2 diabetes is increasingly being diagnosed in children and adolescents.
Gestational diabetes is a form of glucose intolerance that is diagnosed in some women during pregnancy. Gestational diabetes occurs more frequently among African Americans, Hispanic/Latino Americans, and American Indians. It is also more common among obese women and women with a family history of diabetes. During pregnancy, gestational diabetes requires treatment to normalize maternal blood glucose levels to avoid complications in the infant. After pregnancy, 5 to 10 percent of women with gestational diabetes are found to have type 2 diabetes. Women who have had gestational diabetes have a 20 to 50 percent chance of developing diabetes in the next 5 to10 years.
Treatment of diabetes
In order to survive, people with type 1 diabetes must have insulin delivered by a pump or injections.
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.
Many people with diabetes also need to take medications to control their cholesterol and blood pressure.
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.
Prevalence of diabetes
Total: 17 million people–6.2 percent of the population–have diabetes.
Diagnosed: 11.1 million people
Undiagnosed: 5.9 million people
Incidence of diabetes
New cases diagnosed per year: 1 million people aged 20 years or older.
Deaths among people with diabetes
In 1999, approximately 450,000 deaths occurred among people with diabetes aged 25 years and older. This figure represents about 19 percent of all deaths in the United States in people aged 25 years and older.
Overall, the risk for death among people with diabetes is about 2 times that of people without diabetes. However, the increased risk associated with diabetes is greater for younger people (that is, 3.6 times for people aged 25 to 44 years versus 1.5 for those aged 65 to 74 years) and women (that is, 2.7 times for women aged 45 to 64 years versus 2 for men in that age group).
Diabetes was the sixth leading cause of death listed on U.S. death certificates in 1999. This is based on the 68,399 death certificates in which diabetes was listed as the underlying cause of death. Diabetes was listed as a contributing cause of death on an additional 141,265 death certificates. However, many decedents with diabetes do not have the disease entered on their death certificate; only about 35 to 40 percent have it listed anywhere on the certificate and only about 10 to 15 percent have it listed as the underlying cause of death.
Complications of diabetes
Heart disease is the leading cause of diabetes-related deaths. Adults with diabetes have heart disease death rates about 2 to 4 times higher than adults without diabetes.
The risk for stroke is 2 to 4 times higher among people with diabetes.
High blood pressure
About 73 percent of adults with diabetes have blood pressure greater than or equal to 130/80 mm Hg or use prescription medications for hypertension.
Diabetes is the leading cause of new cases of blindness among adults 20 to 74 years old.
Diabetic retinopathy causes from 12,000 to 24,000 new cases of blindness each year.
Diabetes is the leading cause of treated end-stage renal disease, accounting for 43 percent of new cases.
In 1999, 38,160 people with diabetes began treatment for end-stage renal disease.
In 1999, a total of 114,478 people with diabetes underwent dialysis or kidney transplantation.
Nervous system disease
About 60 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.
Severe forms of diabetic nerve disease are a major contributing cause of lower-extremity amputations.
More than 60 percent of non-traumatic lower-limb amputations in the United States occur among people with diabetes.
From 1997 to 1999, about 82,000 non-traumatic lower-limb amputations were performed each year among people with diabetes.
Periodontal or gum diseases are more common among people with diabetes than among people without diabetes. Among young adults, those with diabetes are often at twice the risk of those without diabetes.
Almost one third of people with diabetes have severe periodontal diseases with loss of attachment of the gums to the teeth measuring 5 millimeters or more.
Complications of pregnancy
Poorly controlled diabetes before conception and during the first trimester of pregnancy can cause major birth defects in 5 to 10 percent of pregnancies and spontaneous abortions in 15 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.
Uncontrolled diabetes often leads to biochemical imbalances that can cause acute life-threatening events, such as diabetic ketoacidosis and hyperosmolar (nonketotic) coma.
People with diabetes are more susceptible to many other illnesses and, once they acquire these illnesses, often have a worse prognosis than people without diabetes. For example, they are more likely to die with pneumonia or influenza than people who do not have diabetes.