Immunotherapy with cytokines can induce delirium (IL-2, IFN) (Adams et al., 1988; Lerner et al., 1999; van Steijn et al., 2001) and increased systemic cytokines and acute phase proteins (IL-6, IL-8, CRP) are associated with delirium post hip fracture (Beloosesky et al., 2007; de Rooij et al., 2007; van Munster et al., 2008). This evidence concerns the gene IFNA1 and hip fracture.