What NIH Statistics Reveal About Diabetes Prevalence

Author(s): 
By John Steinberg, DPM

Given the trends indicating the increasing prevalence of diabetes in the United States, this national health concern has commanded a drastic increase in general public media attention. According to an American Diabetes Association study, the overall costs for diabetes total $98 billion, with direct medical costs of $44 billion and indirect expenses (such as disability, work loss and premature mortality) adding up to $54 billion.
There are numerous statistics and information sources which can help you achieve to establish a better understanding of the disease and its impact on the health care system. However, no information source is more universally accepted than the National Institutes of Health (NIH). Without further delay, let’s take a closer look at some of the NIH statistics.
Type 2 diabetes may account for about 90 to 95 percent of all diagnosed cases of diabetes. 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. Practitioners are also increasingly diagnosing type 2 diabetes in children and adolescents.
Impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) are considered prediabetic conditions and studies suggest they may be reversible. IGT is a condition in which the blood glucose level is elevated (between 140 and 199 milligrams per deciliter or mg/dL in a two-hour oral glucose tolerance test) but is not high enough to be classified as diabetes. IFG is a condition in which the fasting blood glucose level is elevated (between 110 and 125 mg/dL after an overnight fast) but is not high enough to be classified as diabetes. Among U.S. adults 40 to 74 years old, 16 million have IGT and 10 million have IFG.

How Common Is Diabetes?
Seventeen million people or 6.2 percent of the population have diabetes, according to the National Institutes of Health. Of these, 5.9 million persons with diabetes remain undiagnosed.
About 151,000 people under the age of 20 have diabetes. Clinic-based reports and regional studies indicate type 2 diabetes is becoming more common among American Indian, African-American, Hispanic and Latino children and adolescents.
NIH statistics show that 16.9 million people age 20 or older have diabetes and one million new cases of diabetes are diagnosed per year in this population group. This breaks down to 2,200 new cases a day. The incidence of diabetes is much higher in those over 65. In fact, 20.1 percent of this population has diabetes. Among those 65 and over, 7 million or 20.1 percent have diabetes.
In the U.S., an estimated 7.8 million men of all ages have diabetes while 9.1 million women (of all ages) have the disease.
There continues to be a higher prevalence of the disease among minority populations. Diabetes affects 11.4 million non-Hispanic whites and 2.8 million non-Hispanic blacks. On average, non-Hispanic blacks are two times more likely to have diabetes than non-Hispanic whites of similar age.
According to NIH estimates, 2 million Hispanic/Latino Americans have diabetes. On average, Hispanic/Latino Americans are 1.9 times more likely to have diabetes than non-Hispanic whites of similar age. Mexican Americans, the largest Hispanic/Latino subgroup, are two times more likely to have diabetes than non-Hispanic whites of similar age. Similarly, residents of Puerto Rico are two times more likely to have diagnosed diabetes than non-Hispanic whites in the U.S.
Sufficient data are not available to derive more specific current estimates for other groups. Of those American Indians and Alaska Natives who receive care from the Indian Health Service (IHS), 105,000 have diabetes. At the regional level, diabetes is least common among Alaska natives (5.3 percent) and most common among American Indians in the southeastern United States (25.7 percent) and in certain tribes from the southwest. On average, American Indians and Alaska natives are 2.6 times more likely to have diabetes than non-Hispanic whites of similar ages.
Prevalence data for diabetes among Asian-Americans and native Hawaiians or other Pacific Islanders are limited. Some groups within these populations are at increased risk for diabetes. For example, data collected from 1996 to 2000 suggest native Hawaiians are 2.5 times more likely to have diagnosed diabetes than similarly aged white residents of Hawaii.

What Studies Say About Prevention
Research studies in the United States and abroad have found that lifestyle changes can prevent or delay the onset of type 2 diabetes among high-risk adults. These studies, which lasted three to six years, included people with IGT and other high-risk characteristics for developing diabetes. Lifestyle interventions included diet and moderate-intensity physical activity (such as walking for two hours each week). This study found that these interventions led to a 40 to 60 percent reduction in the risk of developing diabetes for for both sexes and all age and racial and ethnic groups.
Studies have also shown medications have been successful in preventing diabetes in some population groups. In 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 for younger, heavier people (those 25 to 40 years of age who were 50 to 80 pounds overweight) and less effective among older people and people who were not as overweight.

How Common Are Complications?
Emphasizing prevention efforts is more critical than ever when you consider the array of diabetes-related complications. Heart disease, for example, is the leading cause of diabetes-related deaths. Adults with diabetes have heart disease death rates about two to four times higher than in adults without diabetes. The risk for stroke is two to four times higher among people with diabetes. 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 between 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, according to NIH statistics. In 1999, 38,160 people with diabetes began treatment for end-stage renal disease. The same year, a total of 114,478 people with diabetes underwent dialysis or kidney transplantation.
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 nontraumatic lower-limb amputations in the United States occur among people with diabetes. From 1997 to 1999, about 82,000 nontraumatic lower-limb amputations were performed each year among people with diabetes.

Final Notes
In 1999, approximately 450,000 deaths occurred among people with diabetes age 25 and older, representing about 19 percent of all deaths in the United States of that age group, according to NIH statistics.
Overall, the risk for death among people with diabetes is about two times that of people without diabetes. However, the increased risk associated with diabetes is greater for younger people (3.6 times the risk for people age 25 to 44 versus 1.5 times the risk for those age 65 to 74) and women (2.7 times the risk for women age 45 to 64 versus two times the risk for men in that age group).
Diabetes is the sixth leading cause of death in the U.S. Diabetes was listed as a contributing cause of death on an additional 141,265 death certificates. However, these numbers may be underestimated. According to NIH estimates, diabetes is listed on only about 35 to 40 percent of the death certificates of people with diabetes and only about 10 to 15 percent have it listed as the underlying cause of death.

Dr. Steinberg (pictured) is an Assistant Professor in the Department of Orthopedics/Podiatry Service at the University of Texas Health Science Center.




References:

Additional References 1. American Association of Diabetes Educators: www.aadenet.org 2. American Diabetes Association: www.diabetes.org 3. Centers for Disease Control and Prevention: www.cdc.gov/diabetes and www.cdc.gov/nchs 4. Centers for Medicare and Medicaid Services: www.hcfa.gov 5. Department of Veterans Affairs: www. va.gov/health/diabetes 6. Health Resources and Services Administration: www.hrsa.gov 7. Indian Health Service: www.ihs.gov 8. Juvenile Diabetes Research Foundation International: www.jdrf.org 9. National Council of La Raza: www.nclr.org 10. National Diabetes Education Program, a joint program of NIH and CDC: http://ndep.nih.gov and www.cdc.gov/diabetes 11. National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health: www.niddk.nih.gov 12. U.S. Department of Health and Human Services Office of Minority Health: www.omhrc.gov Source: National Institute of Diabetes and Digestive and Kidney Diseases. National Diabetes Statistics fact sheet: general information and national estimates on diabetes in the United States, 2000. Bethesda, Md.: U.S. Department of Health and Human Services, National Institutes of Health, March 2002.

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