Multiple myeloma and family history of cancer among blacks and whites in the U.S.

BACKGROUND: In the U.S., the incidence rate of multiple myeloma is more than twice as high for blacks as for whites, but the etiology of this malignancy is not well understood. METHODS: A population-based case-control interview study of 565 subjects (361 white, 204 black) with multiple myeloma and 2104 controls (1150 white, 954 black) living in 3 areas of the U.S. offered the opportunity to explore whether family history, of cancer contributes to the risk of multiple myeloma and explains the racial disparity in risk. RESULTS: For both races combined, the risk of multiple myeloma was significantly elevated for subjects who reported that a first-degree relative had multiple myeloma (odds ratio [OR] = 3.7, 95% confidence interval [CI] = 1.2-12.0). Increased risk was also associated with a family history of any hematolymphoproliferative (HLP) cancer (OR = 1.7, 95% CI = 1.0-2.8), especially in a sibling (OR = 2.3, 95% CI = 1.1-4.5). The risk associated with familial occurrence of HLP cancer was higher for blacks than for whites, but the difference between the ORs was not statistically significant. CONCLUSIONS: These data are consistent with previous studies that indicate a familial risk of multiple myeloma, but they explain little of the race-related difference in incidence rates.