GPR15 and endothelial dysfunction: Indeed two genes in our model, LRRN3 and GPR15, are among the top differentially expressed genes in blood between current and never smokers according to a meta-analysis by Huan et al. [60] Their presence in our predictive model may be because of the higher proportion of smokers in IA group or because these genes are capturing biological mechanisms related to smoking that are important in IA pathogenesis, such as endothelial dysfunction [61–63].