(HealthDay News) -- The number of Americans with diabetes rose from 26 million in 2010 to 29 million -- 9 percent of the population -- in 2012, a new federal government study finds.One in every four people with diabetes does not even realize it, according to the report from the U.S. Centers for Disease Control and Prevention.
Another 86 million American adults -- more than one-third of adults -- have what doctors call "prediabetes. " This means their blood sugar levels are higher than normal but not yet high enough to be classified as type 2 diabetes, the CDC said.
Rates of prediabetes are similar for blacks (39 percent), Hispanics (38 percent) and whites (35 percent).
"These new numbers are alarming, and underscore the need for an increased focus on reducing the burden of diabetes in our country," Ann Albright, director of CDC's Division of Diabetes Translation, said in an agency news release.
Diabetes falls into two main categories: type 1, an autoimmune illness which is often inherited and involves a dysfunction of insulin-producing cells in the pancreas; and type 2, which develops over time and is tied closely to obesity. Between 90 percent and 95 percent of diabetes cases are of the type 2 variety, according to the U.S. National Institutes of Health.
Without taking measures such as weight loss and increased exercise, 15 percent to 30 percent of people with prediabetes typically go on to develop type 2 diabetes within five years, the CDC report said.
"Diabetes is costly in both human and economic terms. It's urgent that we take swift action to effectively treat and prevent this serious disease," Albright said.
According to the new report, 1.7 million people aged 20 and older were diagnosed with diabetes in 2012. The epidemic seems to be hitting minorities hardest: Blacks, Hispanics and American Indian/Alaska Native adults are about twice as likely to have diagnosed diabetes as white adults, the CDC found.
Diabetes is striking more people at a younger age as well. Among Americans younger than age 20, 208,000 have already been diagnosed with either type 1 or type 2 diabetes, according to the report, which is based on health data from 2012.
At the same time, total medical costs and lost work and wages associated with diabetes and its complications rose from $174 billion in 2007 to $245 billion in 2012.
One expert said the new numbers were discouraging but not unexpected.
"The increasing number of people with diabetes in the United States and worldwide is not surprising to the caregivers at the front lines of the epidemic," said Dr Ronald Tamler, clinical director of the Mount Sinai Diabetes Center at The Mount Sinai Hospital in New York City.
However, he stressed that, "while a third of the country is at risk for developing diabetes, it can be prevented with lifestyle changes. Patients with diabetes can live full, active lives, but need to seek out comprehensive medical care to avoid the complications of their condition."
Left untreated, diabetes boosts the risk of serious health problems such as heart disease, stroke, vision loss, kidney failure, limb amputation and premature death. Diabetes can be managed through physical activity, diet and the use of insulin and medications to lower blood sugar levels.
It's also important for diabetes patients to take steps to reduce heart disease risk factors such as high blood pressure, high cholesterol and smoking, the CDC said.
Another diabetes care expert questions whether the resources are there to care for all these patients.
"With more people identified, we need more resources and providers to care and educate them," said Dr. Loren Wissner Greene, Clinical Associate Professor at the NYU School of Medicine in New York City.
"Unless diabetes can be prevented or well treated and blood sugar controlled, we face an escalating and devastating future of human and financial cost," she said.