Population-based Epidemiologic Study of Childhood Diabetes in Chicago: a) Disease Surveillance; b) Family Studies; c) Questionnaire Followup.

The goal of this study is to investigate the epidemiology and natural history of childhood-onset diabetes, whether of autoimmune, non-autoimmune, or mixed etiology in affected probands and their relatives. The following hypotheses frame the research questions to be addressed:

Hypothesis 1. Diabetes as it occurs in youth derives from a spectrum of etiologic processes, from the insulinopenia of autoimmune type 1 to obesity-related, insulin-resistant type 2 diabetes. A subset of children develop diabetes through a combination of the 2 major etiologic pathways, with autoimmune ß-cell destruction aggravated by the presence of insulin resistance related to genetic susceptibility, obesity and/or physical inactivity. A fraction of young patients are unclassifiable at onset due to severe symptomatology and ambiguities in measures of ß-cell function. This poses the research challenge of misclassification of disease, as well as the clinical difficulty of potentially inappropriate treatment ... Since patients are drawn from the city-wide registry, clustering of genetic and behavioral risk factors will be systematically identified without the selection bias inherent in case series and clinic-based studies.

Research questions:

1. Is it feasible to distinguish type 1 from early-onset type 2 diabetes at diagnosis? Which demographic, clinical, and family characteristics are most useful?
2. Is the risk of developing diabetes among siblings of early-onset type 2 or mixed cases equivalent to that for siblings of type 1 patients? Which characteristics are most predictive of risk? Hypothesis 2. Changes in the epidemiologic parameters of childhood diabetes over the past 2 decades are directly related to changes in the prevalence of risk factors for both type 1 and type 2 diabetes, including obesity, physical inactivity, and perinatal exposures.

Research questions: