The negative association of serum bilirubin with T2DM observed in our study as well as other previous studies seems to be plausible when taking into account the signaling activities of bilirubin reported in recent studies (as reviewed in [2,3,4]), in particular its beneficial effects on PPARα [33] and AMPK signaling [34]. The gene discussed is PPARA; the disease is type 2 diabetes mellitus.