Table 2 Results of the natural effect models consisting of sexual exposure groups as the exposure variable, biomarkers (cytokines, microbial species, or their combined effects) as the mediators, and HIV-1 infection status as the outcome variable

G2–G1

1.92

0.64

0.003

<0.001

sCD14, sCD163

G3–G1

2.56

0.61

0.001

G4–G1

3.55

0.7

0.001

G2–G1

2.08

0.68

0.002

<0.001

A. muciniphila, B. caccae, B. fragilis, B. uniformis, Bacteroides spp., Butyricimonas spp., Dehalobacterium spp., Methanobrevibacter spp., Odoribacter spp.

G3–G1

2.61

0.64

0.001

G4–G1

3.58

0.71

0.001

G2–G1

1.81

0.64

0.005

<0.001

sCD14, sCD163, A. muciniphila, B. caccae, B. fragilis, B. uniformis, Bacteroides spp., Butyricimonas spp., Dehalobacterium spp., Methanobrevibacter spp., Odoribacter spp.

G3–G1

2.38

0.61

0.001

G4–G1

3.16

0.68

0.001

G2–G1

0.11

0.1

0.284

0.007

sCD14, sCD163

G3–G1

0.12

0.09

0.168

G4–G1

0.33

0.14

0.023

G2–G1

0.02

0.13

0.879

0.033

A. muciniphila, B. caccae, B. fragilis, B. uniformis, Bacteroides spp., Butyricimonas spp., Dehalobacterium spp., Methanobrevibacter spp., Odoribacter spp.

G3–G1

0.15

0.13

0.264

G4–G1

0.35

0.17

0.045

G2–G1

0.2

0.17

0.241

0.001

sCD14, sCD163, A. muciniphila, B. caccae, B. fragilis, B. uniformis, Bacteroides spp., Butyricimonas spp., Dehalobacterium spp., Methanobrevibacter spp., Odoribacter spp.

G3–G1

0.29

0.17

0.087

G4–G1

0.74

0.24

0.002