For 43 of 87 proteins, higher levels including C-reactive protein (CRP) [HR (95% CI) 3.3 (1.3–8.2), P = 0.009], Neurofilament light (NEFL) [HR (95% CI) 4.3 (1.2–15.5), P = 0.03] and Guanosine diphosphate dissociation inhibitor 1 (GDI1) [HR (95% CI) 3.4 (1.2–9.4), P = 0.02] were associated with progression to dementia. The gene discussed is CRP; the disease is dementia.