Fifteen years ago, type 2 diabetes in children was almost unheard of. Since then, as the number of cases has crept up, scientists have sought to figure out how best to treat this type of diabetes in young people. A 2007 study in the Journal of the American Medical Association estimated that there are about 3,700 new cases of type 2 diabetes a year among youth in the United States. The evidence suggests that type 2 behaves differently in children than in adults, an insight that may help doctors give kids with type 2 the best possible care.
|Kids With Diabetes in the U.S., 2009 (Under age 20)|
|More than 19,000 have type 2|
|More than 168,000 have type 1|
|Source: SEARCH trial|
In June, researchers from the SEARCH for Diabetes in Youth study released data showing that type 2 diabetes in 10- to 19-year-olds had increased 21 percent between 2001 and 2009. “Twenty-one percent is substantial,” says Elizabeth Mayer-Davis, MSPH, PhD, RD, of the University of North Carolina–Chapel Hill, who is a SEARCH researcher. “That was really driven by the Hispanic and non-Hispanic white youth.” Type 2 diagnosis rates didn’t increase in Native Americans, Asian/Pacific Islanders, or African Americans during these years. This may be good news, says Mayer-Davis, suggesting that rates may be leveling off, but only time will tell. The researchers also noted that the number of cases of type 2 rose faster among girls than in boys.
SEARCH researchers excluded children under 10 years old from their calculations. “Really, type 2 diabetes is exceedingly rare under the age of 10,” says Mayer-Davis, a former American Diabetes Association president of health care and education. The great majority of people with diabetes under 21 years old have type 1, she adds. In 2009, only 1 in 3,000 people between ages 10 and 19 had type 2 diabetes. With type 1, there were 6 cases per 3,000 people between newborn and 19. However, the ratio of type 1 to type 2 diabetes varies among ethnic groups. In new cases of diabetes among African American adolescents over 10 years old, “about 40 percent have type 1 and 55 percent or so have type 2,” says Mayer-Davis. With non-Hispanic white kids, 80 percent are being diagnosed with type 1.
The main culprit for the rise in type 2 among children, experts agree, is weight. “We don’t even entertain the possibility of type 2 when a child isn’t overweight,” says Silva Arslanian, MD, a pediatric endocrinologist at the Children’s Hospital of Pittsburgh. Obesity isn’t the only factor, though. Many kids are overweight and don’t develop diabetes, says Mayer-Davis, so something must lead the beta cells of the pancreas to stop producing enough insulin to control blood glucose in children who develop type 2. That part, she says, remains a mystery.
A complicating factor is that obesity is rising among type 1s as well, just as in the general population. “It becomes hard to make the distinction,” says Arslanian, between type 1 and type 2 diabetes in children. To confirm that a child has type 2, doctors can check the blood for autoantibodies, the hallmark of type 1.
Prevention and Treatment
Because type 2 in kids is such a recent phenomenon, doctors still don’t have a gold-standard treatment. To address this knowledge gap, scientists conducted the Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study, which included 700 children between 10 and 17 with recently diagnosed type 2 diabetes. All participants started on metformin to achieve an A1C (average blood glucose over the previous two to three months) of 8 percent or less. Then a third of kids continued metformin, another third took metformin and rosiglitazone (Avandia), and the rest added a weight-loss program to their metformin. Over an average of four years, researchers tracked how many of the children failed to maintain an A1C of 8 percent or less. None of the regimens worked particularly well: By the study’s end, about half the kids in all the groups had experienced a decline in blood glucose control that required treatment with insulin.
The researchers learned that the need for insulin in type 2 comes “three times faster in children than in adults,” says Arslanian. “As of now, it looks like the deterioration in beta cell function in teenagers occurs sooner than in adults.” This suggests that type 2 in kids progresses rapidly. However, at least part of the reason so many kids with type 2 are on insulin is because they have limited options. There is an abundant selection of medications for type 2 in adults. But in children, the only approved diabetes meds are metformin and insulin.
Diabetes complications are a concern in children with uncontrolled type 2. “A higher percentage of kids with type 2 than type 1 have complications,” such as kidney disease, says Mayer-Davis. Children with type 2 often have risk factors for heart disease, such as high blood pressure and high LDL (“bad”) cholesterol. Kids with these conditions are at increased risk for heart attacks and strokes as adults, so Arslanian says it’s important to treat these risk factors with medications that improve cholesterol and blood pressure. The American Diabetes Association also recommends that children with type 2 get annual screenings for diabetic eye and kidney disease.
The future for adolescents with type 2 diabetes is still uncertain. The condition is so new that scientists don’t know what will happen when these kids grow up. But that’s changing, as researchers continue to learn more about the disease in youth. The goal is to establish a gold standard for treatment so that kids with type 2 get the care they need to become healthy adults.