ORIGINAL ARTICLE: CLINICAL Incidence rates of the major leukemia subtypes among U.S. Hispanics, Blacks, and non-Hispanic Whites MATTHEW J. MATASAR 1,2 , ELLEN K. RITCHIE 2,3 , NATHAN CONSEDINE 4 , CAROL MAGAI 4 , & ALFRED I. NEUGUT 1,2,3 1 Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA, 2 Department of Medicine, College of Physicians & Surgeons, Columbia University, New York, NY, USA, 3 Herbert Irving Comprehensive Cancer Center, College of Physicians & Surgeons, Columbia University, New York, NY, USA and 4 Long Island University, Brooklyn, NY, USA (Received 18 October 2005; accepted 3 May 2006) Abstract While leukemia rates are thought to be lower in South and Central America, no study has systematically investigated incidence rates of the leukemia subtypes among Hispanics in the U.S. This was a retrospective cohort study, using data from the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute, 1992 – 2001, to compare leukemia incidence rates as a function of race and ethnicity. It was found that in adults, Hispanics had lower incidence rates for each of the major types of leukemia as compared to non-Hispanic Whites: For AML, elderly Whites had an incidence rate ratio (IRR) of 1.61 in comparison to Hispanics (p 5 0.001) and 1.27 in comparison to Blacks (p 5 0.001); for CML, the IRR among the elderly was 1.42 that of Hispanics (p 5 0.001) and 1.22 that of Blacks (p ¼ 0.003); and for CLL, the IRR was 2.31 times that of Hispanics (p 5 0.001) and 1.48 times that of Blacks (p 5 0.001). In ALL, however, Hispanics aged 0 – 19 had a significantly higher incidence rate than Whites and Blacks, with an IRR of 1.32 compared to Whites (p 5 0.001), and 2.62 compared to Blacks (p 5 0.001). In AML, CML, and CLL, among people age 65 or older, white non-Hispanics have higher incidence rates than Blacks, and Blacks have higher incidence rates than Hispanics. Childhood ALL incidence rates are highest among Hispanics, and lowest among Blacks. Keywords: Leukemia [epidemiology], ethnic groups, SEER program Background Despite recent therapeutic advances, there are ex- pected to be 23 300 deaths from leukemia in the U.S. in 2004 [1]. While genetic and environmental exposures have been identified as risk factors for leukemia, these can account for only a minority of cases, with the majority having no clearly identifiable cause [2]. Several recent reports have examined leukemia incidence among specific populations in an attempt to gain insights into its etiology; they have found that overall leukemia incidence rates differ by race (greater among Whites than Blacks or Asian-Americans) and by gender (greater among men than women) [3 – 5]. Little is known, however, about the incidence of leukemia or its subtypes among American Hispanics, although studies have suggested that Hispanic children have a greater incidence of acute lymphocytic leukemia (ALL) than non-Hispanic children [6,7]. Materials and methods We conducted a population-based investigation to determine the incidence rates among Hispanics of the major leukemia subtypes and to determine whether their incidence rates differed from those of white non-Hispanics (here, ‘‘Whites’’) or Blacks. The Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute is a collection of 11 population-based tumor registries covering approximately 14% of the U.S. population; the SEER database is comparable to the total U.S. Correspondence: Alfred I. Neugut, Department of Epidemiology, Mailman School of Public Health, 722 West 168 th Street, R725, New York, NY 10032, USA. Tel: 212 305 9414. Fax: 212 305 9413. E-mail: ain1@columbia.edu 5mailto:ain1@columbia.edu4 Leukemia & Lymphoma, November 2006; 47(11): 2365 – 2370 ISSN 1042-8194 print/ISSN 1029-2403 online Ó 2006 Informa UK Ltd. DOI: 10.1080/10428190600799888