Dana Dabelea, M.D., Ph.D., of the University of Colorado Health Sciences Center, Denver, presented the findings of the study at a JAMA media briefing in New York.

Estimates of the incidence of type 1 diabetes mellitus (DM) show an increase in incidence worldwide during the past two decades, according to background information in the article. Type 2 DM has traditionally been viewed as a disorder of adults, most likely persons who are middle-age or elderly. But as the prevalence of obesity has increased in recent decades, some studies have reported an increasing proportion of youth with type 2 DM, especially among racial/ethnic minority populations. However, data are limited regarding the types and incidence of DM among U.S. youth of different racial/ethnic backgrounds.

Dr. Dabelea and colleagues with the SEARCH for Diabetes in Youth Study Group identified the cases of DM among individuals younger than 20 years in the U.S. to estimate the population incidence of type 1 and 2 DM overall and by age and race/ethnicity. The study included 2,435 multi-ethnic youth with newly diagnosed DM in 2002 and 2003, from 10 locations in the U.S.

Overall, the incidence rate (per 100,000 person-years [the number of individuals in the study times the number of years of follow-up per person]) of DM was 24.3. The incidence rate was highest among 10- to 14-year-old youth (33.9), and slightly higher in females vs. males. Overall, the highest incidence rates of DM were observed among non-Hispanic white (26.1), African American (25.4), and American Indian youth (25.0), with lower rates among Hispanic and Asian-Pacific Islander youth.

For children age 0 to 4 years and 5 to 9 years, most DM was type 1, regardless of race/ethnicity. The incidence of type 1 DM was highest among non-Hispanic white children, and lowest among American Indian and Asian-Pacific Islander children. Similarly, for older youth (10-14 years and 15-19 years), the incidence of type 1 DM was highest among non-Hispanic white children, followed by African American and Hispanic youth.

"... taken together [with other studies], these data suggest that the incidence of type 1 DM may be increasing in the United States, consistent with worldwide trends," the authors write. "We estimate that the annual number of newly diagnosed youth with type 1 DM in the United States is approximately 15,000."

Overall, type 2 DM was relatively infrequent, but the highest rates were documented among 15- to 19-year-old minority groups, including American Indian youth, followed by African American, Asian-Pacific Islander, and Hispanic youth. "Although the evidence of the presence of type 2 DM in youth is still developing, it is consistent with the increasing prevalence of type 2 DM in adults, and the increasing prevalence of obesity in both adults and children."

"The SEARCH study provides unique population-based data on the incidence of DM among youth of various racial/ethnic backgrounds, according to DM type. Continuing this surveillance effort will document temporal trends in the incidence of DM among various racial/ethnic groups and accurately assess the future health care burden of DM and its complications in the U.S. pediatric and young adult population," the researchers conclude.

Reference: JAMA. 2007;297:2716-2724.

Editorial: Incidence of Diabetes in Children and Youth--Tracking a Moving Target

In an accompanying editorial, Rebecca B. Lipton, Ph.D., M.P.H., B.S.N., of the University of Chicago, comments on the findings of Dabelea and colleagues.

"The SEARCH project adds some detail to the understanding of the changing nature of diabetes risk in the United States. The authors have ascertained cases in a range of settings, under the stringent privacy regulations that have constrained much population-based research in the United States recently. In particular, their group is well positioned to examine geographic differences in diabetes risk among the diverse locations represented in the SEARCH study."

"As this and other research goes forward, it may be possible to develop a better understanding of the interplay of autoimmunity with youth-onset diabetes. There is an urgent need to go beyond studies such as this one by implementing a coordinated approach to childhood diabetes surveillance (i.e., mandated case-reporting). Only then can society respond effectively to the serious and increasing challenge of diabetes in youth."

Reference: JAMA. 2007;297:2760-2761.

Note: If no author is given, the source is cited instead.

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