Urban-rural variation in childhood type 1 diabetes incidence in Canterbury, New Zealand, 1980-2004.

Geographical variation in the incidence of childhood type 1 diabetes is well documented. Such patterns are thought to give clues to the potential causes of this complex disease. This study examined the urban-rural differences in childhood type 1 diabetes in the Canterbury region of New Zealand between 1980 and 2004. We found significantly higher incidence of childhood type 1 diabetes in satellite urban communities, which could not be explained by the ethnic composition, neighbourhood deprivation, population density or household overcrowding in these areas. Varying levels of immigration and or/commuting in different urban-rural settings could explain this finding. This study highlights the value of geographical investigations for aetiological hypothesis generation.