GFAP and Alzheimer disease: There was a significant SN:group interaction in predicting GFAP (b = −117.33, SE = 43.17, t[53] = −2.72, p < 0.01) due to a significant negative relationship in controls (b = −90.51, SE = 41.31, t[20] = −2.19, p = 0.04), but not in AD (p > 0.05).