Nearly one in five American teenagers has an abnormal glucose level, according to new government data.

The findings were published in a research letter in the July 19 issue of the Journal of the American Medical Association by Andy Menke, PhD, an epidemiologist with Social & Scientific Systems (under contract to the US National Institutes of Health) and colleagues.

Using both interview and examination results from 2606 adolescent participants aged 12 to 19 in the 2005–2014 National Health and Nutrition Examination Survey (NHANES), investigators found a nearly 1% prevalence of diabetes — more than a quarter undiagnosed — and a nearly 18% prevalence of prediabetes.

NHANES did not distinguish between type 1 and type 2 diabetes.

Dr Menke told Medscape Medical News that although over 80% of teenagers with diabetes have type 1, "We found a relatively high percentage of young people were unaware of their diabetes, as well as a high prevalence of prediabetes....These youth are likely predominantly people with type 2 diabetes or, for those with prediabetes, at high risk for type 2 diabetes....Our findings suggest that adolescents in the United States are developing type 2 as well as type 1 diabetes."

Both prediabetes and undiagnosed diabetes were more common in male, non-Hispanic black, and Hispanic teens compared with females and non-Hispanic whites.

However, Dr Menke noted, "Our study was not designed to identify risk factors for undiagnosed diabetes or prediabetes in adolescents. Further research needs to be conducted to better identify those adolescents who will benefit from diabetes screening."

In the interim, he said, "physicians may need to better screen the youth at high risk for diabetes based on the guidelines for their adult counterparts and to educate people on the risk factors for type 1 and type 2 diabetes."

Prediabetes, Undiagnosed Diabetes Higher in Minority Teens

NHANES is a series of 2-year stratified, multistage surveys representative of the general civilian US population. It includes in-person surveys in which participants are asked if they had ever been diagnosed with diabetes by a health professional. In addition, there are examinations involving a 75-g oral glucose tolerance test, fasting blood glucose, and HbA 1c testing. Diabetes and prediabetes were defined by standard criteria.

"To our knowledge, our study is the first to use all three American Diabetes Association recommended markers to diagnose diabetes in a nationally representative study of US adolescents," Dr Menke noted.

Of the 2606 adolescents included, 62 had diabetes — of whom 20 were undiagnosed — and 512 had prediabetes. The weighted prevalence of diabetes was 0.8%, of which 28.5% was undiagnosed.

The prevalence of prediabetes, 17.7%, was "higher than we anticipated," Dr Menke said.

Prediabetes was more common in males than females (22.0% vs 13.2%).

Compared with white adolescents, in whom the percentages with undiagnosed diabetes was 4.6% and prediabetes was 15.1%, higher rates were seen among black participants (49.9% undiagnosed diabetes and 21.0% prediabetes, respectively) and Hispanics (39.5% and 22.9%).

Neither the prevalence of diabetes nor that of prediabetes changed over time.

According to Dr Menke, "a previous study found 87% of teens with diagnosed diabetes had type 1 diabetes, and this is likely in the ballpark of the percentage with type 1 diabetes in our study."

He told Medscape Medical News that although study participants who reported insulin use were more likely to have type 1 diabetes while those who did not use insulin were more likely to have type 2 diabetes, "there are exceptions for both, so we can't consider insulin use to be accurate criteria to determine diabetes type. Likewise, weight-for-height criteria are not well-established for adolescents and also vary within types of diabetes. This is indeed an area where further research is necessary."

The study was funded by a contract from the National Institute of Diabetes and Digestive and Kidney Diseases. The authors had no relevant financial relationships.

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JAMA. 2016;316:344-345. Extract