Genomic DNA was isolated from whole blood using standard procedures. For the Health 2000 study sample, A118G SNP (rs1799971, Asn40Asp) was genotyped using the fluorogenic 5′ nuclease assay method (TaqMan®) and pre-designed primers and probes (Taqman® SNP Genotyping Assay C__8950074_1_, Applied Biosystems, Foster City, CA, USA) and Applied Biosystems 7300 Real Time PCR System (Applied Biosystems) according to manufacturer's protocols. In the FINRISK sample, genotyping was done using Sequenom MassARRAY System and iPLEX Gold chemistry (Sequenom, San Diego, California), according to the manufacturer's instructions, whereas the genotyping of the HBCS cohort was conducted with the Illumina 610k Quad Bead chip by the Wellcome Trust Sanger Institute.
