Study: Diabetes prevalence has doubled in past 25 years

BALTIMORE — Cases of diabetes and pre-diabetes in the United States have nearly doubled since 1988, suggests new research released Tuesday from the Johns Hopkins Bloomberg School of Public Health, with obesity apparently to blame for the surge. The researchers also found that the burden of the disease has not hit all groups equally, with alarming increases in diabetes in blacks, Hispanics and the elderly.

According to new research reported in the April 15, 2014 issue of the Annals of Internal Medicine, diabetes increased from 6% to 10% in the past two decades, and pre-diabetes also doubled in prevalence over the same period. Depending on the definition used, current estimates of the prevalence of pre-diabetes range from 12% to 30% in the population. "There is a growing need to recognize this serious issue, especially since most cases of diabetes can be prevented through weight loss and other lifestyle changes," stated lead author, Elizabeth Selvin, an associate professor at the Johns Hopkins Bloomberg School of Public Health.

In 2010, approximately 21 million American adults ages 20 years or older had confirmed diabetes — either diagnosed or undiagnosed. The investigators analyzed data from more than 43,000 participants collected over two decades in the National Health and Nutrition Examination Surveys. 

While diabetes has increased dramatically in the population, the investigators found that the proportion of cases of diabetes that are undiagnosed has decreased. Currently, only 11% of diabetes cases in the U.S. population are undiagnosed, suggesting major improvements in screening and diagnosis of diabetes during the last two decades. "The implications of the increase in pre-diabetes and diabetes are enormous, but the good news is we are doing better with screening and diagnosis," Selvin said.

The investigators found a greater prevalence of pre-diabetes and diabetes, particularly undiagnosed diabetes, in ethnic minorities compared with whites. This disparity has increased over the past 20 years. "The substantially greater prevalence of pre-diabetes and diabetes, and poor rates of glycemic control — even among persons with medication-treated diabetes — in ethnic minority populations is particularly concerning," Selvin said. "Especially since blacks and Mexican Americans also are at a greater risk for complications of diabetes."

Total diabetes in blacks was nearly double the prevalence in whites (15% vs. 9%). Mexican Americans also had a greater prevalence of diabetes than whites (12% vs. 9%). Racial and ethnic differences also existed in treatment of diabetes and glycemic control. Among persons diagnosed with diabetes who reported currently taking medications, only 52% of non-Hispanic blacks and 43% of Mexican Americans had HbA1c levels less than 7% compared with 57% of non-Hispanic whites.