GenABEL34 was used to test all 4.6 billion possible combinations of SNPs and expression traits (299 352 SNPs*15 439 traits) for significant associations. Here, we assumed a genetic model in which both alleles contribute to gene expression in an additive manner, because this has been shown to be one of the most powerful statistical approaches.36 The SNP-trait associations were adjusted for sex, age, smoking, alcohol consumption, diagnosis, C-reactive protein level, cholestatic liver disease and presurgical medication as covariates (Supplementary Table S1), using an additive linear model.
