Non-Hodgkin's Lymphoma and Sunlight

Abstract

Incidence and mortality rates for nonHodgkin's lymphoma (NHL) continue to rise dramatically throughout the world (7,2). Changes in diagnostic practices and in levels of exposure to the established risk factors for NHL (including genetic predisposition, immunosuppression, infection with human immunodeficiency virus [HIV], and various occupational exposures) cannot account for the long-term, worldwide increases (3). On the basis of epidemiologic and experimental observations, some investigators (4,5) recently suggested that sunlight may contribute to the development of NHL and its upward trend. In particular, the rise in NHL incidence parallels the global rise in melanoma incidence (6), patients with NHL are at an elevated risk of developing melanoma (7-10), and experimental data show immunosuppressive effects of UV radiation that may predispose to melanoma or other cancers (//). The hypothesis that sunlight exposure may affect NHL risk (4Jj,10) prompted us to review the geographic patterns of mortality rates in the United States for the following three decades: 1950-1959, 1960-1969, and 1970-1980 (12). In white men and white women, NHL mortality was consistently lower in the southern half of the United States, particularly during the earliest period. In contrast, mortality from melanoma of the skin and nonmelanoma skin cancer A. White men