Cox proportional hazards models were used to assess the ability of CSF YKL-40/Aβ42, tau/Aβ42, and ptau/Aβ42 to predict (top) conversion from cognitive normalcy (CDR 0) to cognitive impairment (CDR>0) and (bottom) progression from very mild dementia (CDR 0.5) to mild or moderate dementia (CDR>0.5). Biomarker measures were analyzed as both continuous and categorical variables, and were converted to standard Z-scores to allow comparison of hazard ratios between different biomarkers. In evaluating risk, analyses were adjusted for age and gender. Abbreviations: HR, hazard ratio; CI, confidence interval.