Facts and Figures on Diabetes
- In 2002, an estimated 6.3 percent of the population, or some 18.2 million persons, had diabetes in the U.S..
- About 70 percent are aware of their disease (13.0 million) compared to 30 percent (5.2 million) who are unaware .
- Diabetes affects various sociodemographic groups unequally. Persons aged 65 years and over make up almost 40 percent of all the persons with diagnosed diabetes, and this age group has a prevalence rate over 10 times that of persons under 45 years of age . Minority populations also are disproportionately affected, with the prevalence of diabetes generally 1.5 to 4 times higher in those groups than in the majority population (Figure 2) [17, 18]. A higher prevalence in adults is associated with a lower educational level; adults with less than a high school education are more than twice as likely to have diabetes than college graduates .
- Rates of diabetes among adults also vary by geography; in 2001, prevalence ranged from 5.0 percent in Minnesota to 10.5 percent in Alabama . The highest reported diabetes prevalence in the world (over 50 percent) is among the Pima Indians of the southwestern U.S. .
- Diabetes also imposes a tremendous economic burden, estimated at $132 billion in 2002 in the U.S. Most of this is spent on medical care for those affected ($92 billion) but a substantial proportion is also due to disability, work loss, and premature mortality ($40 billion) . Unemployment and reduced productivity may also be manifestations of disability. The work disability rate is over three times as high for persons with diabetes as for those without the disease (26 percent versus 8 percent) . Generally, diabetes results in the loss of about one third of a year’s earnings.
An increasingly large proportion of people in the U.S. have diabetes (Figure 2). High health care costs are associated with this condition, and the consequences to individuals, families and society in terms of quality of life are even more staggering. Diabetes is a disease in which blood glucose (sugar) levels are elevated either because of the body’s failure to make adequate amounts of the hormone insulin and/or failure of cells to respond to insulin. There are several types of diabetes:
- Type 1 diabetes, often called “insulin-dependent diabetes mellitus” or juvenile-onset diabetes, develops when the body’s immune system destroys pancreatic beta cells, the cells in the body that make the hormone insulin that regulates blood glucose. Thus, the pancreas can no longer produce insulin. This form of diabetes usually strikes children and young adults, but it may occur at any age, and requires individuals to take several insulin injections a day or use a pump to survive. Type 1 diabetes may account for 5 to 10 percent of all diagnosed cases of diabetes. [13, 14]
- Type 2 diabetes, formerly termed “adult-onset diabetes” is “non-insulin dependent diabetes mellitus,” even though some affected individuals require insulin for control of the disease. Type 2 diabetes usually begins as insulin resistance, a disorder in which cells do not use insulin properly. As it progresses, the pancreas gradually loses its ability to produce insulin. Type 2 diabetes often appears after age 40, although it is now being diagnosed increasingly in children and adolescents. This form of diabetes accounts for 90 to 95 percent of all diagnosed cases of diabetes. [13, 14] .
- Gestational diabetes mellitus (GDM) is a form of diabetes that affects between 2.5 percent and 4 percent of women in the U.S. during pregnancy. This type of diabetes results from the body's resistance to the action of insulin. The increased resistance during pregnancy is caused by hormones produced in the placenta. Gestational diabetes usually ends after the baby is born, but women with gestational diabetes have up to a 45 percent risk of recurrence with the next pregnancy and up to a 63 percent risk of developing type 2 diabetes later in life .
- Prediabetes is a condition that affects millions of people. It is defined as impaired fasting glucose or impaired glucose tolerance (IGT) or both. People with prediabetes are at high risk for developing full-blown diabetes and are also at risk of developing other serious health problems such as heart attack and stroke. Recently, the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus of the American Diabetes Association lowered the blood glucose level threshold for diagnosis of impaired fasting glucose from 110mg/dl to 100mg/dl in order to provide a more reliable means of identifying persons at risk for developing diabetes . This lowered threshold for impaired fasting glucose doubled the number persons identified as having prediabetes. As estimated in the CDC’s National Diabetes Fact Sheet, over 40 million Americans aged 40-74 years have prediabetes.
Figure 2. Prevalence of Diabetes: Diagnosed and Undiagnosed
Source: Centers for Disease Control and Prevention. Diabetes Surveillance System. Atlanta, GA,
U.S. Department of Health and Human Services.
Available at http://www.cdc.gov/diabetes/statistics/index.htm.
Over the last half century there has been a 4- to 8-fold increase in the prevalence of diagnosed diabetes in the U.S. [17, 18] . Projections of diabetes into the 21st century are not comforting (Figure 3). A 165 percent increase in persons with diabetes in the U.S. is projected between 2000 and 2050, a rise from 11 to 29 million diagnosed persons of all ages  . Those aged over 75 years are expected to have the largest increases (271 percent in women and 437 percent in men). Among racial and ethnic groups, African Americans are expected to have a larger increase (363 percent for males and 217 percent for females) than Caucasians (148 percent for males and 107 percent for females).
Figure 3. Prevalence of Diagnosed Diabetes in the United States
Source: Data for 1960-1998 from the National Health Interview Survey, NCHS, CDC
Projected data for 2000-2050 from the Behavioral Risk Factor Surveillance System, Division of Diabetes Translation, CDC
Diabetes can have a major impact on both the quality and length of life. Acute complications, such as dangerously low blood glucose levels, called hypoglycemia, could be life-threatening. Chronic complications--such as eye disease leading to blindness, kidney disease leading to kidney failure, lower extremity nerve disease leading to amputations, and premature cardiovascular disease leading to heart disease and stroke-- are ultimately the main causes for reductions in the quality and also the length of life of persons with diabetes (Table 1).
Annual Number of Cases Associated with Diabetes
|Blindness||12,000 – 24,000|
|Cardiovascular disease deaths||130,000|
Diabetes is the major cause of kidney failure, lower limb amputations and adult-onset blindness. Diabetes increases cardiovascular disease risk 2-4 fold.
Among the elderly, diabetes-related cognitive impairment or dementia is also well recognized. Diabetes is the sixth leading cause of death and lowers average life expectancy by up to 15 years  .
High quality of care for diabetes is based on ensuring that people with diabetes have needed tests that can help them and their providers manage their condition. All people with diabetes should obtain these services, which are relatively inexpensive to provide. However, only 20.7 percent of patients reported having received all five major tests for diabetes within the past 2 years. 
Many factors have affected the upward trends in the prevalence of diabetes, including changes in diagnostic criteria, enhanced detection, decreasing general mortality, changes in population demographics (e.g., aging and growth in minority populations who experience higher prevalence rates), and increased incidence. Demographic changes in the population such as increases in minority populations at higher risk (37 percent), increasing prevalence rates (36 percent), and population growth (27 percent) have increased the diabetes burden. The concomitant rise in obesity and the elevated risk it presents for type 2 diabetes are also major contributors to these increases. The prevalence of overweight or obesity significantly increased from 1988-94 to 1999-2000 (from 55.9 percent to 64.5 percent); and obesity also rose (from 22.9 percent to 30.5 percent)  . The prevalence of overweight in children has doubled and in adolescents has tripled since 1970 (rising from 11 percent in 1988-94 to 15 percent in 1999-2000) .
While it is not yet possible to prevent type 1 diabetes, findings from major clinical trials have demonstrated that the onset of type 2 diabetes can be prevented or delayed in high-risk groups, including minority groups, who carry a disproportionately heavy burden of this disease. Clinical research has identified risk factors that place individuals at high-risk for this disease. Because over 5 million people are currently undiagnosed in the U.S., and because more intensive treatment of hypertension and hyperlipidemia is recommended for people with diabetes to reduce their increased risk of cardiovascular disease, the U.S. Preventive Services Task Force recommends that people with elevated levels of blood lipids (such as cholesterol and triglycerides) or high blood pressure be screened for type 2 diabetes  .