The incidence of diffuse large B-cell lymphoma (DLBCL) among Hispanic individuals and chronic lymphocytic leukemia (CLL) among non-Hispanic black individuals was associated with urban status, according to a study reported in Clinical Lymphoma, Myeloma and Leukemia.
Using the 21 Surveillance, Epidemiology, and End Results (SEER) population-based registries for the period of 2000 to 2016, study researchers identified 328,118 adults with non-Hodgkin lymphoma (NHL), many of whom had DLBCL (136,917 cases). The remaining cases had either CLL (120,319 cases) or follicular lymphoma (FL; 70,882 cases).
Most DLBCL cases were non-Hispanic white (73.6%), followed by with Hispanic (11.8%) and non-Hispanic black (7.3%). The racial and ethnic distribution was similar for CLL and FL cases. Nearly 90% of cases for all 3 subtypes lived in metropolitan urban areas, and the rest lived in non-metropolitan urban areas (4%) or less urban or rural areas (6%).
A multivariate analysis that adjusted for age, sex, and family poverty revealed an overall higher incidence of DLBCL in metropolitan urban areas compared with rural areas (incidence rate ratio [IRR], 1.20; 95% CI, 1.11-1.30).
Also revealed was a higher incidence of DLBCL for Hispanics living in nonmetropolitan urban (IRR, 1.32; 95% CI, 1.16-1.51) and metropolitan urban areas (IRR, 1.55; 95% CI, 1.36-1.76) compared with living in rural areas.
In addition, for non-Hispanic blacks, living in a nonmetropolitan urban area was linked to a higher incidence of CLL compared with living in a rural area (IRR, 1.49; 95% CI, 1.27-1.72).
“Overall, our findings suggest that factors related to urban status may be associated with DLBCL and CLL pathogenesis,” the study authors wrote. “Our results may help provide epidemiological clues to understanding the racial disparities seen among hematological malignancies, particularly regarding the risk of DLBCL in Hispanics and CLL in non-Hispanic blacks.”
Blansky D, Mantzaris I, Rohan T, and Hosgood III HD. The influence of rurality, race and ethnicity on non-Hodgkin lymphoma incidence [published online May 16, 2020]. Clin Lymphoma Myeloma Leuk. doi: 10.1016/j.clml.2020.05.010