Figure 1From: The causal effect of red blood cell folate on genome-wide methylation in cord blood: a Mendelian randomization approachThe structure of an observation study to assess the association between exposure (A) and outcome (Y) in the presence of both measured (C) and unmeasured confounding (U); Z represents a possible instrument for an instrumental variable analysis. In this study, A represents log transformed RBC folate, the outcome Y is site-specific methylation, C is intention to conceive, our surrogate for confounding by periconceptional behaviors, and our instrument Z is MTHFR genotype modeled additively.Back to article page