Nearly one-third of U.S. adults age 65 and older have diabetes, while an additional 30 percent have pre-diabetes, researchers said.
"We’re facing a diabetes epidemic that shows no signs of abating, judging from the number of individuals with pre-diabetes," lead author Catherine Cowie of the National Institute of Diabetes and Digestive and Kidney Diseases, a part of the National Institutes of Health said in a statement.
"For years, diabetes prevalence estimates have been based mainly on data that included a fasting glucose test but not an oral glucose tolerance test," Cowie said in a statement. "The addition of the oral glucose tolerance test gives us greater confidence that we’re seeing the true burden of diabetes and pre-diabetes in a representative sample of the U.S. population."
The oral glucose tolerance test gives more information about blood glucose abnormalities than the fasting blood glucose test, which measures blood glucose after an overnight fast. The fasting blood glucose test is easier and less costly than the oral glucose tolerance test , but the two-hour test is more sensitive in identifying diabetes and pre-diabetes, especially in older people, Cowie explained.
The 2005-2006 National Health and Nutrition Examination Survey is the first national survey in 15 years to include the oral glucose tolerance test.
The study, published in Diabetes Care, also found 13 percent of adults age 20 and older have diabetes, but 40 percent of them have not been diagnosed.
According to a CDC report in October, diagnosed diabetes cases went up by more than 90 percent among U.S. adults over the past 10 years. From 4.8 cases per 1,000 population during 1995-97, the number climbed up to 9.1 per 1,000 people in 2005-07 in 33 states.