Gut microbiota causally affects longitudinal changes in brain structure: a large-scale mendelian randomization study

However, the causal relationship between the gut microbiota and structural changes in the brain remains undetermined. Gut microbiota data from genome-wide association (GWAS) meta-analyses summarized by the MiBioGen consortium were used (n=13,266) and screened for instrumental variables.

Data from the ENIGMA consortium's GWAS meta-analysis of morphological changes in the brain were summarized as outcomes (n=15, 640). The relationship between gut microbiota and longitudinal changes in brain structure was detected using random effects inverse variance weighting (IVW), MR-Egger, MR-Weighted Median, MR-Simple Mode, and MR-Weighted Mode, and sensitivity analysis was performed. IVW estimates showed that Verrucomicrobia (β=-18.15, 95%CI: -30.25 to -6.05, P=3.27E-03) significantly attenuated the longitudinal volume changes of the putamen, Firmicutes (β=10.77, 95%CI:3.30 to 18.25), P=4.73E-03), Cyanobacteria (β=7.68, 95%CI:2.46 to 12.90, P=3.93E-03) and Gastranaerophilales (β=9.54, 95%CI:4.41 to 14.68, P=2.69E-04) significantly increased the longitudinal volume variation of pallidum.