The association between elevated peripheral inflammatory marker concentrations including C-reactive protein (CRP) and interleukin-6 (IL-6), and cognitive decline has been reported in cross-sectional studies of the general population (Oztürk et al., 2007; Alley et al., 2008) and in people with AD and MCI (Guerreiro et al., 2007; Magaki et al., 2007; Roberts et al., 2009). This evidence concerns the gene IL6 and Alzheimer disease.