MULTIPLE-MYELOMA AMONG BLACKS AND WHITES IN THE UNITED-STATES - THE ROLE OF CHRONIC ANTIGENIC-STIMULATION

Multiple myeloma (MM) is twice as common among Blacks than Whites in t he United States. The reasons for this racial disparity are unknown, a nd the etiology of this cancer, in general, is poorly understood. Repe ated or chronic antigenic stimulation (CAS) of the immune system has b een suggested as a risk factor. Previous case-control studies have rep orted inconsistent CAS associations based on evaluations of individual and biologic categories of medical conditions. Interview data from 57 3 cases and 2,131 population-based controls were used to investigate f urther the CAS hypothesis using an immunologically based approach, and to determine whether CAS accounts for the excess of myeloma among Bla cks. Over 50 medical conditions were grouped into biologically and imm unologically related categories, and B-cell- and T-cell-mediated respo nse groups. Except for urinary tract infections among Black men (odds ratio [OR] = 2.0), no significantly increased risks of MM were observe d. However, there was a suggestion of increased risk among Blacks with an increased exposure to anaphylactic conditions. Analysis by immunog lobulin type revealed significantly elevated risks of IgG myeloma with eczema (OR = 2.1), the biologic category 'allergic conditions' (OR = 1.6), and the immunologic category 'anaphylaxis response' (OR = 1.6) a mong Whites, with Blacks having slightly lower risks. Our findings do not support a causal relationship between CAS and MM, nor do they expl ain the higher incidence among Blacks.