Relationship Between Ambient Ultraviolet Radiation And Non-Hodgkin Lymphoma Subtypes: A Us Population-Based Study Of Racial And Ethnic Groups

Associations between ultraviolet radiation (UVR) exposure and non-Hodgkin lymphoma (NHL) have been inconsistent, but few studies have examined these associations for specific subtypes or across race/ethnicities. We evaluated the relationship between ambient UVR exposure and subtype-specific NHL incidence for whites, Hispanics and blacks in the United States for years 2001-2010 (n=187,778 cases). Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were calculated for UVR quintiles using Poisson regression. Incidence was lower for the highest UVR quintile for chronic/small lymphocytic/leukemia (CLL/SLL) (IRR=0.87, 95% CI: 0.77-0.97), mantle cell (IRR=0.82, 95% CI: 0.69-0.97), lymphoplasmacytic (IRR=0.58, 95% CI: 0.42-0.80), mucosa-associated lymphoid tissue (MZLMALT) (IRR=0.74, 95% CI: 0.60-0.90), follicular (FL) (IRR=0.76, 95% CI: 0.68-0.86), diffuse large B-cell (IRR=0.84, 95% CI: 0.76-0.94;), peripheral T-cell other (PTCL) (IRR=0.76, 95% CI: 0.61-0.95) and PTCL not otherwise specified (PNOS) (IRR=0.77, 95% CI: 0.61-0.98). Trends were significant for MZLMALT, FL, DLBCL, BNOS and PTCL, with FL and DLBCL still significant after Bonferroni correction. We found interaction by race/ethnicity for CLL/SLL, FL, Burkitt, PNOS and MF/SS, with CLL/SLL and FL still significant after Bonferroni correction. Some B-cell lymphomas (CLL/SLL, FL and Burkitt) suggested significant inverse relationships in whites and Hispanics, but not in blacks. Some T-cell lymphomas suggested the most reduced risk for the highest quintile of UVR among blacks (PNOS and MF/SS), though trends were not significant. These findings strengthen the case for an inverse association of UVR exposure, support modest heterogeneity between NHL subtypes and suggest some differences by race/ethnicity.What's new? Studies have yielded mix results as to whether exposure to ultraviolet radiation (UVR) increases or decreases risk of non-Hodgkin lymphoma (NHL). In the present analysis of data from population-based cancer registries in the United States, increasing ambient UVR exposure was associated with a reduction in risk of most NHL subtypes, The reduction occurred for all races, including non-Hispanic whites, Hispanic whites, and blacks. The findings emphasize the importance of exploring NHL etiology according to subtypes and across races and ethnicities, as NHL is increasingly recognized as comprising a diverse group of cancers, each potentially involving unique mechanisms.