Exposure to Trace Elements and Risk of Skin Cancer: A Systematic Review of Epidemiologic Studies.

Exposure to environmental trace elements has been studied in relation to many cancers. However, an association between exposure to trace elements and skin cancer remains less understood. Therefore, we conducted a systematic review of published epidemiologic literature examining the association between exposure to trace elements, and risk of melanoma and keratinocyte carcinoma in humans. We identified epidemiologic studies investigating exposure to arsenic, cadmium, chromium, copper, iron, selenium, and zinc and risk of skin cancer in humans. Among the minerals, arsenic, selenium, and zinc had more than five studies available. Exposure to arsenic was associated with increased risk of keratinocyte carcinoma, while too few studies existed on melanoma to draw conclusions. Exposure to selenium was associated with possible increased risk of keratinocyte carcinoma. Studies of zinc and skin cancer were case-control in design and were found to have inconsistent associations. The data on the association between cadmium, chromium, copper, and iron and risk of skin cancer remain too sparse to draw any conclusions. In summary, epidemiologic studies on exposure to trace elements and cutaneous malignancies are limited. Studies with larger sample sizes and prospective designs are warranted to improve our knowledge of trace elements and skin cancer.