GFAP and Atrophy: In bivariate analyses, older age (r = −0.11, p = 0.029), male sex (t = −3.00, p = 0.003), larger ICV (r = −0.17, p < 0.001), larger WML volume (r = −0.16, p = 0.002), carrying an APOEe4 allele (t = −2.71, p = 0.007), having a lower Aβ42/40 ratio (t = −4.05, p < 0.001), and higher levels of p-tau181 (r = −0.22, p < 0.001), GFAP (r = −0.15, p = 0.003), and NfL (r = −0.34, p < 0.001) were significantly associated with the residual measure (i.e. worse than expected cognitive trajectory given the level of atrophy).