IFNA1 and perivascular space measurement: Moreover, early IFN therapy was associated with lower prevalence of PVS among GC users (odds ratio [OR] 0.21, 95% CI 0.10–0.43), while an insignificant but opposite trend was observed in nonusers (OR 1.99, 95% CI 0.91–4.35) (Fig. 1e, f).