GFAP and Alzheimer disease: GFAP in AD showed an even steeper early effect, with HRs of 13.3 (95% CI, 10.3–17.2) at 2 years, 4.64 (95% CI, 4.06–5.29) at 5 years, and 2.09 (95% CI, 1.96–2.23) at 10 years.