2.2 Data sources
Each bacterial taxon was regarded as a separate exposure. Following
multiple steps, the instrumental variables of each bacterial taxon were
acquired from the largest genome-wide association study (GWAS) of human
gut microbiota, which comprised 18340 individuals from 24 cohorts, 14363
(>78%) were European ethnic participants [12]. The
data could be derived athttps://mibiogen.gcc.rug.nl/.
A total of 196 gut microbiota were selected after excluding 15 bacterial
taxa with unknown family or genus (Supplementary Table 1), which finally
included 9 phyla, 16 classes, 20 orders, 32 families, and 119 genera. MN
was regarded as the outcome variable in this study. The SNPs were
acquired from the website:https://gwas.mrcieu.ac.uk/datasets/ebi-a-GCST010005/.
The GWAS data of MN included nine case-control cohorts composed of 4841
East Asian and 7979 European populations.