Although fewer than one percent of adolescents had diabetes, more than 17 percent had prediabetes, according to an analysis of the National Health and Nutrition Examination Survey (NHANES).

Lead researcher Andy Menke, PhD, of Social & Scientific Systems, Inc. in Silver Spring, Maryland, and colleagues published their results online in JAMA on July 19.

They identified 2,606 adolescents between 12 and 19 years old who participated in NHANES from 2005 to 2014. The participants completed a questionnaire and shared information whether a doctor or other healthcare professional had diagnosed them with diabetes.

They also had their hemoglobin A1c (HbA1c) and fasting plasma glucose measure, had an oral glucose tolerance test administered using 75 g of glucose and had their two-hour plasma glucose measured using venipuncture.

The researchers defined diabetes as a previous diabetes diagnosis, HbA1c of 6.5 percent or more, a fasting plasma glucose level of 126 mg/dL or more or a two-hour plasma glucose level of 200 mg/dL or more. They defined prediabetes as not having diabetes and having a HbA1c level of 5.7 percent to 6.4 percent, a fasting plasma glucose level of 100 mg/dL to 125 mg/dL or a two-hour plasma glucose level of 140 mg/dL to 199 mg/dL.

Of the participants, 0.8 percent had diabetes, of which 28.5 percent were undiagnosed. In addition, 17.7 percent of adolescents had prediabetes, including 22.0 percent of males and 13.2 percent of females.

Further, 15.1 percent of non-Hispanic white participants, 21.0 percent of non-Hispanic black participants and 22.9 percent of Hispanic participants had prediabetes. Further, 4.6 percent, 49.9 percent and t39.5 percent of participants, respectively, had undiagnosed diabetes.

During the study, the prevalence of diabetes and prediabetes did not change over time, according to the researchers.

“These findings may have important public health implications because diabetes in youth is associated with early onset of risk factors and complications,” they wrote.

The researchers cited a few limitations of the study, including that participants self-reported whether they had a previous diabetes diagnosis. In addition, the participants did not have a repeat measurement of their HbA1c, fasting plasma glucose and 2-hour plasma glucose level readings, which may have led to an overestimation of diabetes prevalence. Further, they could not distinguish between the type of diabetes, although they said a previous study found 87 percent of adolescents with diabetes had type 1 diabetes.