Figure 1

Overview and assumptions of the Mendelian randomization study. Assumption 1 (Relevance assumption): IVs need to have a stable and robust correlation with the exposure; Assumption 2 (Independence assumption): IVs are independent of any confounders affecting the exposure-outcome relationship; Assumption 3 (Exclusiveness assumption): IVs can only affect the outcome indirectly through the exposure, and not through other approaches.