Sun exposure, vitamin D, and risk of Hodgkin and non-Hodgkin lymphoma.

Similarities in the epidemiology of melanoma, other skin cancers, and non-Hodgkin lymphoma (NHL) have led to the hypothesis that UV exposure, the major risk factor for cutaneous cancers, could play a role on NHL risk too. Epidemiologic studies, however, including a pooled analysis of 10 case-control studies performed by the Interlymph consortium, have failed to confirm this hypothesis. If anything, an inverse association between sun exposure and NHL risk was reported, which appeared confined to recreational sun exposure. Given that sun exposure is the major determinant of vitamin D status in several populations and that vitamin D has been suggested to protect against cancer at several sites, it has been postulated that vitamin D may protect against NHL. Studies that have investigated the association of nutritional sources of vitamin D or serum levels of 25 hydroxy-vitamin D-an indicator of vitamin D status-with NHL are scanty and not totally consistent. Thus, the epidemiologic evidence to date suggests that sun exposure is not likely to increase NHL risk, whereas the vitamin D-NHL relation remains largely undefined. The paucity of information on the relation of sun exposure or vitamin D with adult Hodgkin lymphoma (HL) or childhood lymphomas prevents any definite conclusion.