Fig. 4

Mediation analysis. A Three mediation pathways were conducted between ANU-ADRI scores and MMSE: (1) ANU-ADRI → t-tau → sTREM2 → MMSE; (2) ANU-ADRI → t-tau → MMSE; (3) ANU-ADRI → sTREM2 → MMSE. The serial mediation pathway via t-tau and sTREM2 was not significant (β ₁ = -0.003, P = 0.408). sTREM2 was not significant mediator for this association (β ₃ = -0.004, P = 0.452), but t-tau was significant mediator for this association (β ₂ = -0.031, P < 0.001). B Three mediation pathways were conducted between ANU-ADRI scores and MoCA: (1) ANU-ADRI → t-tau → sTREM2 → MoCA; (2) ANU-ADRI → t-tau → MoCA; (3) ANU-ADRI → sTREM2 → MoCA. The serial mediation pathway via t-tau and sTREM2 was not significant (β ₁ = -0.004, P = 0.324). sTREM2 was not significant mediator for this association (β ₃ = -0.005, P = 0.377), but t-tau was significant mediator for this association (β ₂ = -0.027, P = 0.002). C Three mediation pathways were conducted between ANU-ADRI scores and MMSE: (1) ANU-ADRI → p-tau → sTREM2 → MMSE; (2) ANU-ADRI → p-tau → MMSE; (3) ANU-ADRI → sTREM2 → MMSE. The serial mediation pathway via p-tau and sTREM2 was not significant (β ₁ = -0.002, P = 0.468). sTREM2 was not significant mediator for this association (β ₃ = -0.004, P = 0.449), but p-tau was significant mediator for this association (β ₂ = -0.023, P = 0.001). D Three mediation pathways were tested between ANU-ADRI scores and MoCA: (1) ANU-ADRI → p-tau → sTREM2 → MoCA; (2) ANU-ADRI → p-tau → MoCA; (3) ANU-ADRI → sTREM2 → MoCA. The serial mediation pathway via p-tau and sTREM2 was not significant (β ₁ = -0.002, P = 0.333). sTREM2 was not significant mediator for this association (β ₃ = -0.005, P = 0.369), but p-tau was significant mediator for this association (β ₂ = -0.018, P = 0.009). These three pathways are presented using green, blue, red lines. All mediation paths are adjusted for APOE ɛ4 allele status. The β coefficients in each path and P-values for mediation effects were calculated by a bootstrap test with 10,000 resampling iteration. The dotted line indicates that the indirect effect is not significant (P ≥ 0.05), the solid line indicates that the indirect is significant (P < 0.05). *P < 0.05, **P < 0.01 and ***P < 0.001