IL6 and Alzheimer disease: In addition, the IFN-γ (β = 0.232, 95% CI 0.044 to 0.419; P = 0.016), IL-6 (β = 0.163, 95% CI 0.002 to 0.324; P = 0.048), and D-dimer (β = 0.179, 95% CI 0.014 to 0.343; P = 0.034) levels were also associated with the presence of AD (as shown in Table 5).