In the United States, nearly 13 percent of adults age 20 and older have diabetes, but 40 percent of them have not been diagnosed, according to epidemiologists from the National Institutes of Health (NIH) and the Centers for Disease Control and Prevention (CDC).
Diabetes is especially common in the elderly: nearly one-third of those age 65 and older have the disease. An additional 30 percent of adults have pre-diabetes, a condition marked by elevated blood sugar that is not yet in the diabetic range. The researchers report these findings in the February 2009 issue of Diabetes Care.
"We're facing a diabetes epidemic that shows no signs of abating, judging from the number of individuals with pre-diabetes," said lead author Catherine Cowie, Ph.D., of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), a part of the NIH.
Diabetes is a group of diseases marked by high levels of blood glucose resulting from defects in insulin production, insulin action or both. It is the most common cause of blindness, kidney failure and amputations in adults and a leading cause of heart disease and stroke.
Type 2 diabetes accounts for up to 95 percent of all diabetes cases and virtually all cases of undiagnosed diabetes. Pre-diabetes, which causes no symptoms, substantially raises the risk of a heart attack or stroke and of developing type 2 diabetes. In its analysis, the team also found that:
Minority groups continue to bear a disproportionate burden. The prevalence of diabetes, both diagnosed and undiagnosed, in non-Hispanic blacks and Mexican- Americans is about 70 to 80 percent higher than that of non-Hispanic whites.
Diabetes prevalence was virtually the same in men and women, as was the proportion of undiagnosed cases.
Pre-diabetes is more common in men than in women (36 percent compared to 23 percent).
Diabetes is rare in youth ages 12 to 19 years, but about 16 percent have pre-diabetes.
"These findings have grave implications for our healthcare system, which is already struggling to provide care for millions of diabetes patients, many of whom belong to vulnerable groups, such as the elderly or minorities," said Griffin P. Rodgers, M.D., director of the NIDDK.
"Of paramount importance is the need to curb the obesity epidemic, which is the main factor driving the rise in type 2 diabetes."