1. Figure 7 Mendelian randomization of overlapping exposures
Figure 7 | Mendelian randomization of overlapping exposures. As triglycerides (TGs) overlap with non-HDL cholesterol (non-HDL-C), adjusting the association of TGs with risk of coronary heart disease (CHD) for non-HDL-C diminishes the causal effect of TGs to null. By contrast, non-HDL-C contains the entire cascade of apolipoprotein B-containing lipoproteins, including intermediate-density lipoprotein cholesterol and LDL cholesterol, meaning that an association persists between non-HDL-C and CHD on adjustment for TGs. The attenuation of the TG–CHD association does not provide any information about the causality of TG, because it adjusts for an overlapping trait. This figure is a schematic representation and should not be interpreted as a formal directed acyclic graph.
Holmes, M. V. et al. (2017) Mendelian randomization in cardiometabolic disease: challenges in evaluating causality
Nat. Rev. Cardiol. doi: /nrcardio