TREM2 and Alzheimer disease: Plasma levels of three proteins had a unidirectional association with AD risk: TREM2 (Table 1, Wald ratio test, beta = −0.13, SE = 0.05, P = 8.4 × 10−17), colony stimulating factor 3 (CSF3) (Wald ratio test, beta = 0.10, SE = 0.02, P = 5.9 × 10−6), and TBCA (inverse variance‐weighted method, beta = ‐0.50, SE = 0.12, P = 1.2 × 10−5).