a proxy search was performed to extract the next closest SNP available in terms of pairwise LD, providing a minimum r2 threshold of 0.8 with the eQTL. These steps were performed using the associations() function in the ieugwasr package. To ensure correct orientation of effect alleles between the eQTL and outcome associations, the SNP effects were harmonized using the harmonise_data() function in TwoSampleMR70 selecting Action 2, which assumes that the alleles are forward-stranded in the GWASs (so no filtering or re-orientation of alleles according to frequency was conducted on the palindromic SNPs). Single-SNP MR was then performed using the mr_singlesnp() function in TwoSampleMR. We reported all of the MR findings that passed a P-value threshold of 5 × 10−5 but note that the Bonferroni-corrected P = 0.05 threshold for multiple-testing correction is P = 1.43 × 10−7.
