Results: 72.4% of subjects (83% MCI and 27% SCD) with a pathological CSF ratio (Aβ42/p-tau) met criteria for dementia during the 5-year follow-up versus 18.7% of subjects from the group with a normal ratio. The pathological CSF ratio was a powerful marker of risk for AD dementia (OR 27.1; 95% CI 10.3-71.2)..