Researchers from Sweden and Denmark have reported that ultraviolet (UV) exposure does not increase the incidence of malignant lymphomas, but instead is associated with a lower incidence of non-Hodgkin’s lymphoma (NHL). The incidence of malignant lymphoma has been increasing over the past several decades in the US population. The reasons for this increase are unknown. In fact, the causes of most lymphomas are unknown, except for the relatively few that are associated with specific bacteria (Helicobacter pylori in gastric lymphoma), or viruses such as the Epstein-Barr virus (Burkitt’s lymphoma), HIV-related lymphomas, body cavity lymphomas (human herpes virus-8) or T-cell lymphoma (HTLV-1). However, none of these specific causes explains the increased incidence of lymphomas observed in recent years.
There is speculation that exposure to chemicals, such as certain solvents, pesticides, herbicides, and water contaminated with nitrate, are responsible for the increased incidence of lymphomas. Another speculation is that the increased incidence of lymphomas is due to an increase in sun exposure.
Researchers carrying out the current study looked at sun exposure in 3,740 patients with non-Hodgkin’s lymphoma, Hodgkin’s lymphoma or chronic lymphocytic leukemia and 3,187 individuals without lymphoma. They found that different types of sun exposure were associated with a decreased incidence of NHL. The types of sun exposure associated with a 30-40% decrease in the incidence of NHL included high frequency of sun bathing, sun vacations and sunburns.
Sun exposure is linked to other types of cancer, though and sunscreen and protective clothing is still a safe bet.
