In the geographic subgroup analysis, significant NSFR blunting was observed in Asian and North American cohorts, whereas the pooled effect for European cohorts approached but did not reach statistical significance ( p = 0.0572).
Regarding control sources (Table 2 and Figure 4 B), significant effect sizes were observed in studies with controls recruited from the community or social settings (SMD = −0.37, 95% CI: [−0.58; −0.16]) and hospitals (SMD = −0.80, 95% CI: [−1.30; −0.29]), with studies using unspecified control sources showing a trend toward significance (SMD = −1.60, 95% CI: [−3.30; 0.09]).