CHI3L1 and Alzheimer disease: Baseline levels of YKL-40 were predictive for cognitive decline in AD (β (SE) 0.65 (0.29), p = 0.03), but not in those who were cognitively normal or had MCI (β (SE) –0.10 (0.13), p = 0.44 and −0.32 (0.19), p = 0.11, respectively).