Logistic regression models were used for all case-control association tests. As the T1D cases and controls were chosen to be well matched geographically, we were able to stratify by the 12 subregions of England, Scotland and Wales to exclude the possibility of confounding by geography with little loss of power. We note that the WTCCC study shows that SNPs with significant geographical variation are limited to a small numbers of chromosome regions1, including the TLR region on chromosome 4p14 described in the present report.
