Ultraviolet radiation and incidence of non-Hodgkin's lymphoma among Hispanics in the United States

Abstract

Non-Hodgkin's lymphoma (NHL) is one of the most common cancers among American Hispanics. Several studies suggest that solar UV radiation (UVR) may be an environmental risk contributing to the rise of NHL over the past decades. These studies focused primarily on light-skinned Caucasian populations; it is unknown what role UVR plays in NHL for Hispanics. We described the incidence of NHL in Hispanics from selected states in the United States between 1989 and 2000. To evaluate the role of UVR, we correlated cancer rates with the UV index and latitude of residency. Variations in NHL incidence rates with estimated amount of UVR among whites and blacks from the selected states were also analyzed. We found that NHL occurred less frequently in Hispanics than in whites. Hispanic men had higher incidence of NHL than Hispanic women. Incidence rates of NHL in Hispanics were inversely associated with estimated amount of UVR as an increase in NHL was observed with decreasing UV index (r = -0.7 in men; r = -0.41 in women) or increasing latitude of residency (r = 0.59 in men; r = 0.48 in women). This trend, although it did not reach statistical significance, was also observed in whites and blacks. Our findings do not support previous reports of a positive association between solar radiation and NHL. The inverse relationship between UVR and incidence of NHL is unexplained but presents the need for generation of hypotheses regarding the epidemiology of causal factors for NHL in the United States. Additional studies should be conducted to clarify whether sunlight exposure contributes to the development of NHL.