Data on 807 incident T1DM cases diabetes and 313 T2DM cases occurring in 2002–03 in South Carolina (SC) and Colorado (CO), 5 counties in Washington (WA), and an 8 county region around Cincinnati, Ohio (OH) among youth aged 10–19 years were obtained from the SEARCH for Diabetes in Youth Study. Geographic patterns were evaluated in a Bayesian framework.
Incidence rates differed between the study regions, even within race/ethnic groups. Significant small-area variation within study region was observed for T1DM and T2DM. Evidence for joint spatial correlation between T1DM and T2DM was present at the county level for SC (rSC=0.31) and CO non-Hispanic Whites (rCO=0.40) and CO Hispanics (rCO=0.72). At the tract level, no evidence for meaningful joint spatial correlation was observed (rSC=−0.02; rCO=−0.02; rOH=0.03; and rWA=0.09).
Our study provides evidence for the presence of both regional and small area, localized variation in type 1 and type 2 incidence among youth aged 10–19 years in the United States.