The prevalence of type 1 diabetes increased 21 percent between 2001 and 2009. At the same time, rates of type 2 diabetes rose 30.5 percent, the study found.
These increases affected both boys and girls, and nearly all racial groups, the researchers noted.
The reasons behind the increases aren't entirely clear, said lead researcher Dr. Dana Dabelea, the associate dean for faculty at the Colorado School of Public Health in Aurora.
"While we do not completely understand the reasons for this increase, since the causes of type 1 diabetes are still unclear, it is likely that something has changed in our environment, both in the U.S. and elsewhere in the world, causing more youth to develop the disease, maybe at increasingly younger ages," she said.
Several reasons for the increase in type 2 diabetes are possible, Dabelea said. "Most likely is the obesity epidemic, but also the long-term effects of diabetes and obesity during pregnancy, which have also increased over time," she noted.
This report shows the increasingly important public health burden that pediatric diabetes represents, Dabelea pointed out. "It also highlights the facts that all racial/ethnic groups are affected by both major forms of diabetes," she said.
The report was scheduled to be published May 7 in the Journal of the American Medical Association to coincide with the May 3 presentation of the study findings at the Pediatric Academic Societies annual meeting in Vancouver, Canada.
In type 1 diabetes, the body does not produce insulin, the hormone needed to convert sugar, starches and other food into energy. In type 2 diabetes, the body does not use insulin properly. This is called insulin resistance. At first, the pancreas makes extra insulin to make up for it. But over time, it isn't able to keep up and can't make enough insulin to keep blood sugar at normal levels.
For the study, Dabelea's team collected data on more than 3 million children and adolescents. When looking for type 1 diabetes, the researchers included people aged 19 years and younger. For type 2, the researchers limited the age range to 10 through 19 years. The incidence of type 2 in children younger than 10 was too low to provide statistically significant numbers, according to the report.
The data came from five centers located in California, Colorado, Ohio, South Carolina, and Washington state, as well as from some American Indian reservations in Arizona and New Mexico.
In 2001, type 1 diabetes had been diagnosed in just under 5,000 youngsters from a group of more than 3 million youth. By 2009, that number rose to almost 6,700, an increase of 21 percent, according to the study authors. The only groups that didn't see an increase in type 1 diabetes were children from 0 to 4 years old, and American Indian children, the study revealed.
For type 2, the researchers looked at a group of almost 2 million children. In 2001, 588 children and teens had been diagnosed with type 2 diabetes. By 2009, 819 kids and teens had type 2, a jump of 30.5 percent, the researchers found. The only ethnic groups that didn't see an increase in type 2 were American Indians and Asian Pacific Islanders.
"Historically, type 1 diabetes has been considered a disease that affects primarily white youth; however, our findings highlight the increasing burden of type 1 diabetes experienced by youth of minority racial/ethnic groups as well," the authors wrote.
The increase for both types of diabetes was seen among boys and girls and among whites, blacks and Hispanics. The biggest increase in both types of diabetes was among those 15 through 19 years of age, the researchers noted.
Of the study, Dr. Robert Ratner, chief medical and scientific officer for the American Diabetes Association, said, "The overall prevalence of diabetes is going to grow progressively, because we've done so much better in keeping these people alive, they are going to live longer. We also know they are going to continue to incur costs for complications."
Diabetes will be a major health care problem over the next two decades, he predicted. "There is a need to pay more attention to the prevention of diabetes, because we are not going to be able to care for all of these people," Ratner said.
Ratner was perplexed by the increase in type 1 diabetes. "Whether it's an interaction between genetics and environment that's increasing autoimmunity -- we really don't know," he said. "It's a major question that needs to be answered."
Dr. Luis Gonzalez-Mendoza, director of pediatric endocrinology at Miami Children's Hospital, was also concerned by the increase in type 1 diabetes.
"Type 1 diabetes seems to be on the rise among teens, almost double what it used to be," he said. "There is something that is acting as a trigger for the immune system to go crazy, because type 1 diabetes is an autoimmune disorder."
For more information on diabetes, visit the American Diabetes Association.