Indoor ultraviolet tanning: what the data do and do not show regarding risk of melanoma and keratinocyte malignancies.

Recreational indoor tanning with ultraviolet (UV) radiation has become popular in recent decades, particularly among teenagers and young adults. The consequences for public health have become an important area of concern. The link between this form of UV exposure and both melanoma and non-melanoma skin cancers has been clarified through multiple lines of evidence from epidemiology and laboratory science reflected in recent reports by multiple prestigious bodies. Some have suggested that this form of indoor tanning has a role in vitamin D generation, but a review of existing evidence suggests that indoor tanning is neither a reliable nor advisable source. In addition, laboratory data suggest that tanning promotes a common molecular intermediate in skin carcinogenesis, DNA damage, which thus precludes the concept of a "safe tan." Finally, emerging evidence links UV signaling in skin to dependency/addiction, thus having implications for the organic (rather than cosmetic) impact of the process. This article presents the epidemiologic and mechanistic data relevant to the safety considerations for indoor tanning.