Multiple myeloma following an episode of community-acquired pneumococcal bacteraemia or meningitis.

The risk of multiple myeloma subsequent to an episode of serious pneumococcal infection has not been ascertained. We identified 328 episodes of community-acquired pneumococcal bacteraemia and 77 episodes of pneumococcal meningitis in 227,000 persons over 40 years of age in the County of North Jutland, Denmark, in the period 1981 to 1996. The incidence rate of a subsequent diagnosis of multiple myeloma was determined by linkage to the Danish Cancer Registry. During 1,218 patient-years of follow-up in the bacteraemia cohort, 7 cases of multiple myeloma were diagnosed compared with 0.13 cases expected (standardized incidence ratio (SIR) 53.5, 95% confidence interval 21.4-111.4). During 444 patient-years of follow-up in the meningitis cohort, 4 cases of multiple myeloma were diagnosed compared with 0.05 cases expected (SIR 83.2, 95% confidence interval 22.6-214.8). Patients who survive an episode of community-acquired pneumococcal bacteraemia or meningitis are at increased risk of being diagnosed with multiple myeloma, but the absolute risk is low.