Census-based cohort study of residential exposure to solar ultraviolet radiation and risk of childhood hematological malignancies in Switzerland

Little is known about the etiology of childhood hematological malignancies (CHM). Ultraviolet radiation (UVR) could have an impact on these cancers through different pathways, such as immunosuppressive effects or photosynthesis of vitamin D. A census-based cohort study in Switzerland, a coutry with strongly varying UVR, evaluated the association between ambient solar UVR and the risk of CHM in children aged 0-15 years. There was a 24% decreased risk of acute lymphoblastic leukemia per one-unit increase of UV index (HR 0.76; 95% CI 0.59-0.98) whereas there was no evidence for an association of UVR exposure with risk of childhood lymphoma (1.14; 0.59-2.19).