FIGURE 1.

A, Illustration of the Mendelian randomization (MR) framework and its main assumptions that the instrument is associated with the exposure (1), the instrument is not associated with (un)measured confounders (2), and the instrument does not influence the outcome other than through the exposure (3). B, Illustration of the MR design when using summary‐level data and the SNP‐exposure association and SNP‐outcome association are taken from two separate GWAS (also known as “two‐sample MR”). GWAS, genome‐wide association studies; SNP, single‐nucleotide polymorphism