For CRP levels of 3 mg/L or higher, ApoE4 carriers had a twofold to threefold increase of risk of AD compared with ApoE3 and ApoE2 carriers (18 of 132 [13.6%] vs 25 of 573 [4.4%] vs 6 of 122 [4.9%]; P = .001). Here, CRP is linked to Alzheimer disease.