Dire Diabetes Outlook Among US Kids and Adolescents: Type 1 and Type 2 on the Rise

June 10, 2012

June 10, 2012 (Philadelphia, Pennsylvania) — The prevalence of type 1 and type 2 diabetes is on the rise in children and adolescents in the US, with new data showing that both forms of diabetes mellitus increased across all ethnicities and in boys and girls, although the largest increase in type 2 diabetes occurred in non-Hispanic white and Hispanic children. Over the past decade, the prevalence of type 1 and type 2 diabetes increased 23% and 21%, respectively. [1]

The findings, presented here at the American Diabetes Association (ADA) 2012 Scientific Sessions, are the latest from a large multicenter study known as SEARCH for Diabetes in Youth, an observational study launched in 2000 that is focused on learning more about diabetes in children and adolescents.

"This is the largest study of childhood diabetes that has ever been conducted in the United States," said study cochair Dr Elizabeth Mayer-Davis (University of North Carolina, Chapel Hill).

Dr Elizabeth Mayer-Davis

"The study started because of concerns that physicians were starting to see adolescents, particularly those of minority ethnicities, emerging with a diagnosis of type 2 diabetes, something we previously thought would occur only in adults. We were also concerned that type 1 diabetes might be increasing over time because of data coming from other studies around the world, but at that point we didn't have the capacity in this country to track the occurrence of either type 1 or type 2 diabetes."

Based on their registry data, the SEARCH investigators said there are approximately 188 000 children and adolescents with diabetes in the US, including 168 000 with type 1 diabetes and 19 000 with type 2 diabetes. The SEARCH data also show that these patients have signs of early chronic complications of the disease, even those who had the disease for a relatively short period of time. In a separate presentation, the researchers report that approximately 12% of patients developed diabetic peripheral neuropathy, including 26% of children with type 2 diabetes [2]. Cardiac neuropathy is also evident in these children, especially those with type 2 diabetes.

"All these data provide evidence that diabetes in youth is not benign," said SEARCH cochair Dr Dana Dabelea (University of Colorado, Denver). Speaking with heartwire , she noted that previous studies of children with diabetes had documented atherosclerosis on carotid intima-media thickness (CIMT) imaging tests and had also shown increases in arterial stiffness. The SEARCH cohort study is expected to provide additional answers about the long-term complications associated with type 1 and type 2 diabetes, she said.

Dr Dana Dabelea

SEARCH: Type 2 diabetes

The SEARCH study includes two components: a registry study of approximately 25 000 children with diabetes, including 4000 children and adolescents with type 2 diabetes, and a cohort study of 3000 children and adolescents with diabetes for at least five years who are currently being followed to evaluate the macrovascular and microvascular complications of the disease. Speaking during a press conference announcing the results of the registry analysis, Dabelea presented data showing trends in the prevalence of diabetes mellitus between 2000 and 2009.

The proportion of children younger than 20 years old with type 2 diabetes increased 21%, up from 2.9 cases per 10 000 children to 3.6 cases in 10 000 children. Again, the increase was observed in boys and girls and in children 10 years of age and older. For those younger than 10, type 2 diabetes remains exceptionally rare.

"Although the proportion of youth with type 2 diabetes was highest in American Indians and African Americans, the increase was particularly observed among non-Hispanic white youth and Hispanic youth," said Dabelea. "This might suggest that pediatric type 2 diabetes is perhaps plateauing in high-risk groups but still catching up in the other racial and ethnic groups."

During the press conference, the researchers noted that while the obesity epidemic is believed to be responsible for the increase in the prevalence of early-onset type 2 diabetes, one of the strongest risk factors for its development is "fetal overnutrition," which is the exposure of the developing fetus to obesity and diabetes during intrauterine life. Unhealthy pregnancies, including babies born to obese women or mothers who gain an excessive amount of weight during pregnancy, create a vicious cycle that perpetuates obesity and type 2 diabetes in the next generation, say the researchers. Dr Giuseppina Imperatore (Centers for Disease Control and Prevention [CDC], Atlanta, GA), who was not involved in the analysis, although the CDC sponsored the study along with the National Institute of Health, told heartwire that childhood obesity has remained relatively stable at 17% in recent years.

Dr Giuseppina Imperatore

During the press conference, Mayer-Davis said the SEARCH data have previously shown that diabetic patients have poor diets, with more than 90% eating more than the daily recommendations of saturated fat. Nearly one in five diabetic adolescents smoke, and 90% of kids with type 2 diabetes are obese. Mayer-Davis also examined time spent watching television in relation to HbA1c levels in 1400 individuals from SEARCH. At baseline, those who watched television for more than three hours daily had higher HbA11c levels than those who watched less, and over time the more television watched translated into higher HbA1c levels, she said.

"This is important because about one-third of youth with diabetes watch TV for more than two hours a day on weekdays," she said. "We also found evidence that more TV watching might be associated with worse lipid profiles, another risk factor for diabetes complications."

Type 1 diabetes also on the rise

The prevalence of type 1 diabetes in children younger than 20 years of age increased 23%, up from 1.7 cases per 1000 individuals in 2000 to 2.1 cases per 1000 individuals in 2009. The increase occurred in male and female children of all ages, except those aged four years old and younger, and in all ethnicities except American Indians. In an analysis restricted to non-Hispanic white children, the group at highest risk for type 1 diabetes, the annual increase in the prevalence of type 1 diabetes was 2.6% annually over the 10-year study period.

"Type 1 diabetes is an autoimmune disease, and although there are many multinational, multicenter studies and efforts focused on identifying factors responsible for this increase, we still don't know the reasons [for the increase]," said Dabelea. "One reason might be that children and infants in contemporary environments are less exposed than in the past to viruses and bacteria that might be needed for normal development of the immune system."

Other potential reasons for the increase include the fact that children are being born bigger and are growing faster early in life, and this has the potential to overload the pancreas, resulting in failure of beta cells in the face of an autoimmune attack, said Dabelea.

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