Incidence of childhood type I and non-type 1 diabetes mellitus in a diverse population: the Chicago Childhood Diabetes Registry, 1994 to 2003.

BACKGROUND

Reports of increasing risk for type 1 (T1) and type 2 diabetes mellitus in youth are emerging, but information on socioeconomically diverse populations is limited.

METHOD

The Chicago Childhood Diabetes Registry is a city-wide study of patients 0-17 years old at onset. Incidence data came from medical records and interviews; census data provided denominators; analyses used Poisson regression. Non-type 1 (nT1) patients had a type 2-like clinical course or related indicators.

RESULTS

There were 1,366 incident cases: 719 in non-Hispanic Black (NHB), 379 in Hispanic, 229 in non-Hispanic White (NHW), and 39 in children of other ethnicities. Average annual incidence was 16.0 (95% CI: 14.6, 17.6)/10(5) for boys, 20.1 (18.3, 22.1)/10(5) for girls, and 18.1 (16.9, 19.3)/10(5) overall. Risk was 21.6 (19.6, 23.8)/10(5) for NHB, 14.6 (13.0, 16.4)/10(5) for Hispanic, and 18.1 (15.9, 20.6)/10(5) for NHW. Children aged 10-14 years experienced the highest incidence, irrespective of ethnicity. T1 was predominant in all ethnic groups, except NHB, where the rates of T1 and nT1 were similar. Over ten years there was a marked increase in all childhood diabetes in Chicago, averaging 2.73% (95% CI: 0.49, 5.02) per annum, adjusted for age. This increase was confined to nT1, with an average annual percent change of +6.23% (2.28, 10.34), while T1 incidence remained stable.

CONCLUSIONS

Incidence of childhood diabetes increased between 1994-2003, driven primarily by nT1, suggesting a role for behavioral and/or environmental determinants of insulin resistance. These estimates are likely to be conservative, if nT1 cases were more apt to be missed.