GFAP and Alzheimer disease: When meta-analyzed based on clinical diagnosis on the AD clinical spectrum, both MCI-AD and AD dementia patients had significantly increased GFAP levels compared with CU individuals (MCI-AD vs CU effect size 1.02, 95% CI 0.68–1.36, p < 0.0001, eFigure 6; AD dementia vs CU effect size 1.33, 95% CI 1.01–1.65, p < 0.0001, eFigure 7).