As much as half the U.S. population has diabetes or pre-diabetes, according to a major medical investigation reported Wednesday, and the earliest phases of the "pre" disease are so silent some people may not know they're affected, doctors said Tuesday.
Based on data from 2012, researchers estimate that between 12 percent and 14 percent of adults nationwide have diabetes and about another 37 percent to 38 percent have pre-diabetes.
Reporting in the Journal of the American Medical Association, scientists from the National Institute of Diabetes and Digestive and Kidney Diseases, along with Maryland-based Social & Scientific Systems, assessed reams of data involving diabetes to draw the new conclusion.
In the same sweeping report researchers also found that more than half of all adult Asian-Americans with diabetes and nearly half of all Hispanic-Americans with diabetes are undiagnosed.
Dr. Joshua Miller, an assistant professor of medicine at Stony Brook University School of Medicine, said the new numbers were not surprising.
"Unfortunately, they're not," he said Tuesday. "If you had a graph that plotted the rate of obesity and overlaid it with a graph of diabetes," the results would be strikingly similar, said Miller, an endocrinologist in the medical school's division of endocrinology and metabolism. He was not involved in the new research.
However, diabetes is one of today's largest public health issues, he said, and pre-diabetes is an equally important concern because treatment through diet and exercise can stave off full-blown diabetes.
Dr. Barbara Keber of Glen Cove Hospital, who chairs the department of family medicine, said patients with pre-diabetes suffer from a "silent disease" and are often unaware they're on a path toward diabetes until kidney problems or heart disease emerge.
"Early diagnosis is extremely important," Keber, a member of the North Shore-Long Island Jewish Health System's Diabetes Task Force, said Tuesday.
The task force has mounted a major effort on Long Island and in Queens to diagnose people with pre-diabetes in an effort to ward off future complications.
Pre-diabetes is determined by a test known as the hemoglobin A1c, or HbA1c exam, Miller said, which provides a two- to three-month reading of a patient's blood sugar.
For people without diabetes, a normal range for the hemoglobin A1c would be about 4 percent to 5.6 percent.
But a reading of 5.7 percent to 6.4 percent indicates pre-diabetes and, therefore, an increased risk of the metabolic disorder, Miller said.
Levels of 6.5 percent or higher indicate diabetes, Miller and other doctors said, noting that 95 percent of people in the country with diabetes have type 2, the form that usually develops in adulthood. The American Diabetes Association estimates that 29 million people in the country have type 1 and type 2 diabetes.
"We have treatments to help people with diabetes, but treatments can only help those who have been diagnosed," Dr. Griffin Rodgers, director of the National Institute of Diabetes and Digestive and Kidney Diseases, said in a statement Tuesday.
The new research published in Wednesday's Journal of the American Medical Association also underscores that not only is diabetes a leading cause of illness and death, but its costs also are astronomical.
Overall expenses linked to the metabolic disorder run about $245 billion annually, an economic burden linked to increased use of health care resources and lost productivity, researchers said.