The percent of U.S. teens with diabetes is on the rise, a new study suggests.

Between 1999 and 2008, the percentage of adolescents ages 12 to 19 with diabetes or prediabetes increased from 9 percent to 23 percent, the study found.

Prediabetes is a condition in which blood sugar levels are abnormally high, but not high enough to be classified as diabetes.

Both diabetes and prediabetes are risk factors for cardiovascular disease, the researchers said.

The researchers did not have data to say whether the children had Type 1 or Type 2 diabetes. The cause of Type 1 diabetes remains unknown; the development of Type 2 diabetes has been linked with poor diet and weight gain.

The study also found 50 that percent of overweight teens, and 60 percent of obese teens had at least one risk factor for cardiovascular disease, including diabetes, borderline-high or high cholesterol levels or high blood pressure (hypertension).

The findings indicate “U.S. adolescents carry a substantial burden of [cardiovascular disease] risk factors, especially those youth who are overweight or obese,” said the researchers from the Centers of Disease Control and Prevention. Studies suggests such risk factors in children can persist into adulthood, the researchers said.

The researchers analyzed information from 3,383 adolescents who participated in a government survey between 1999 and 2008. Participants were interviewed and underwent a physical exam. About one-third were overweight or obese.

Overall, 22 percent of participants had borderline-high or high cholesterol levels, and 15 percent had diabetes or prediabetes during the study period. About 6 percent had low levels of “good” cholesterol, and 14 percent had pre-hypertension or hypertension.

While the percentage of participants who were overweight or obese did not change significantly over the study period, the percentage of those with prediabetes or diabetes increased 14 percent.

The findings indicate that “a large proportion of teens, regardless of their weight, would benefit from interventions that promote healthy lifestyles, including physical activity and eating a healthy diet,” the researchers said.

However, the researchers cautioned that prediabetes and diabetes were diagnosed on the basis of a single blood test, which may not be reliable measure in children.

The study is published in the May 21 issue of the journal Pediatrics.

Pass it on:  The percentage of teens with diabetes or prediabetes increased 14 percent over the last decade.

Editor's note: This article has been updated to reflect the fact that the study did not distinguish between Type 1 and Type 2 diabetes.

Follow MyHealthNewsDaily on Twitter @MyHealth_MHND. Find us on Facebook.