Solarium Use and Risk for Malignant Melanoma: Many Open Questions, Not the Time to Close the Debate.

To shed further light on the ongoing debate whether sunbed use may increase melanoma risk, we have critically assessed the scientific literature that is at present available, focussing on a meta-analysis that we published recently. Our literature search identified several meta-analyses that report a weak association for ever-exposure to UV radiation from a solarium with melanoma risk. However, the quality of studies included in these meta-analyses and the resulting evidence levels and grades of recommendation were very low due to the lack of interventional trials and because of severe limitations of many of the observational studies. The results of cohort and case-control studies published until today do not prove causality, not even by the Hill criteria. The overall quality of these observational studies and the resulting evidence levels are low due to severe limitations (including unobserved or unrecorded confounding), which leads to bias. It must be recognized that in the majority of studies, published to date, many of the confounding factors, including sun exposure, sunburns and skin type, have not been adequately and systematically recorded and adjusted for. We conclude that the many limitations of the individual studies and the resulting low levels of evidence and grades of recommendation do at present not allow postulation of a causal relationship between solarium use and melanoma risk. At present, there is no convincing evidence that moderate/responsible solarium use increases melanoma risk.