In subjects with hypertension, increases in intima-media thickness (IMT) at four years were less in subjects also having high autoantibodies particularly IgM, to phosphorylcholine. The presence or absence of autoantibodies, particularly IgM, against phosphrylcholine is thus related to an increased or decreased risk of developing ischemic cardiovascular diseases. A method to determining antibodies, particularly IgM antibodies, toward phosphorylcholine is proposed in this invention to identify subjects at risk of developing ischemic cardiovascular diseases. Animal experiments show that medium to high levels of antibodies, particularly IgM antibodies, can be detected in plasma after active immunization with a keyhole limpet hemocyanin (KLH)-phosphorylcholine conjugate. Pharmaceutical compositions comprising a phosphorylcholine conjugate or antibody preparations, for example a monoclonal antibody, with specificity to a phosphorylcholine conjugate is proposed as is use of these compositions as active or passive immunogens in the treatment or prevention of atherosclerosis.