Genotyping in the NHS used the Illumina Infinium Sentrix HumanHap550 chip. Detailed methods related to the genotyping have been published previously27. Genotyping in the WGHS used either the Illumina HumanHap300 Duo-Plus chip or the combination of the HumanHap300 Duo and I-Select chips28. In the present analysis, the 317,759 SNPs shared between the NHS and the WGHS samples were almost entirely from the HumanHap300 panel.
