Racial Differences in the Prevalence of Monoclonal Gammopathy in a Community-based Sample of the Elderly

Abstract Purpose: To determine if there is an increased prevalence of monoclonal gammopathy in elderly blacks compared with whites, analogous to the difference in incidence of multiple myeloma reported for the two racial groups and to confirm age and gender relationships. Patients and methods: Subjects were from the Duke Established Populations for the Epidemiologic Study of the Elderly, selected on the basis of stratified random household sampling. Blacks were oversampled to allow for increased statistical precision in racial comparisons. In all, 1,732 subjects (aged >70 years) consented to blood drawing and constitute the sample for this study. Monoclonal immunoglobulins were determined by agarose gel electrophoresis and immunofixation. Results: One hundred six subjects (6.1%) had a monoclonal gammopathy. There was a greater than twofold difference in prevalence between blacks (8.4%) and whites (3.8%) ( P Conclusion: Prevalence of monoclonal gammopathy is significantly greater among blacks than whites in a community-based sample, in approximately the same ratio that multiple myeloma has been reported in the two groups. Given the absence of correlation with environmental factors, there may be a biological racial difference in susceptibility to an early event in the carcinogenic process leading to multiple myeloma.