“…Geographically, most of the studies were conducted in China, accounting for 10 out of the 15 studies [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ], while the remaining studies were divided as follows: three were from Japan [ 32 , 33 , 34 ], one was from Thailand [ 35 ], and one was from Australia [ 36 ]. Study designs comprised eight cross-sectional studies [ 23 , 24 , 25 , 26 , 28 , 31 , 35 , 36 ], six prospective cohort studies [ 22 , 29 , 30 , 32 , 33 , 34 ], and one case–control study [ 27 ]. However, two of the prospective cohort studies only employed a cross-sectional approach to describing the gut microbiomes of their participants and did not include a longitudinal analysis or a comparison of microbiome changes or associations [ 22 , 29 ].…”