No Proven Causal Relationship Between Solarium Use and Melanoma Risk
Based on current evidence, we would like to critically discuss the study’s finding that an estimated 892 (5%) melanomas are due to solarium (UV tanning bed) use (1), before far-reaching conclusions are drawn. The risk estimators come from an older meta-analysis (2), which shows only associations but not causality (3, 4). Studies on this topic face the challenge of adjusting for solar UV exposure and other confounding factors (2, 3). Subgroup analyses of recent meta-analyses (3, 4) support the hypothesis that solarium users are sun worshippers and increase their risk of melanoma due to solar UV radiation.
A recent meta-analysis (3) reports the following risk estimates for association of melanoma rate with solarium use (odds ratios [95% confidence intervals]):
- worldwide (1.19 [1.04; 1.35])
- Europe (1.10 [0.95; 1.27])
- America (1.32 [1.05; 1.66])
- Australia / Oceania (1.30 [1.00–1.69]).
It is unlikely that the lack of statistical significance in the subgroup “Europe” is due to low statistical power, as the association is significant in the subgroup “America” (which has higher levels of solar UV exposure) despite having a significantly lower number of study participants (Europe: 93 630; America: 10 229; Australia: 1083) (3).
The risk estimates used in Gredner et al. (1) are based on a meta-analysis (2) that takes into account worldwide studies. Regional factors, such as levels of solar UV exposure, the ethnicity of the study population, and the legal regulations for solarium use (concerning age restrictions or technical details of equipment) play a major role and differ significantly in individual countries. Thus, only Germany-wide or Europe-wide studies should be considered for calculating the cancer burden in Germany; however, meta-analyses of these studies (3, 4) show no statistically significant differences in the risk for melanoma following solarium use (for instance, odds ratio 1.10 [0.95, 1.27]) in Burgard et al. ).
We therefore consider estimates whether or not (and if so, how many) melanoma cases in Germany can be attributed to the use of solariums scientifically not sufficiently justified.
Prof. Dr. med. Jörg Reichrath
Zentrum für Klinische und Experimentelle Photodermatologie und
Klinik für Dermatologie, Venerologie und Allergologie
Universitätsklinikum des Saarlandes, Homburg
Prof. Dr. med. Stefan Pilz
Medizinische Universität Graz
Klinische Abteilung für Endokrinologie und Diabetologie
Univ.-Prof. Dr. Winfried März
Medizinische Universität Graz, Klinisches Institut für Medizinische
und Chemische Labordiagnostik und Medizinische Fakultät Mannheim
der Universität Heidelberg,
Universitätsmedizin Mannheim, Medizinische Klinik V (Nephrologie, Rheumatologie, Hypertensiologie, Endokrinologie und Diabetologie)
Conflict of interest statement
Prof. Reichrath is member of the Arnold Rikli-Award Jury of the Jörg Wolff Foundation. The Saarland University, together with Prof. Reichrath as one of several responsible group leaders, has received a research grant from the Jörg Wolff Foundation. One goal of the Jörg Wolff Foundation is the promotion of research and teaching on the health impact of natural or artificially generated optical radiation on humans. The foundation holds significant shares of JW Holding GmbH, which is an international group of companies that focuses on the manufacture and sale of radiation sources for cosmetic, medical, and technical applications.
Univ.-Prof. März has received financial support from the companies Siemens Healthingeneers, Aegerion Pharmaceuticals, AMGEN, AstraZeneca, Sanofi, Alexion Pharmaceuticals BASF, Abbott Diagnostics, Numares AG, Berlin-Chemie, Synlab Holding Deutschland GmbH, Akzea Therapeutics, Bayer Vital GmbH, bestbion dx GmbH, Boehringer Ingelheim Pharma GmbH & Co. KG, Immundiagnostik GmbH, Merck Chemicals GmbH, MSD Sharp and Dohme GmbH, Novartis Pharma GmbH, and Olink Proteomics.
Prof. Pilz states that no conflict of interest exists.
|1.||Gredner T, Behrens G, Stock C, Brenner H, Mons U: Cancers due to infection and selected environmental factors—estimation of the attributable cancer burden in Germany. Dtsch Arztebl Int 2018; 115: 586–93 VOLLTEXT|
|2.||Boniol M, Autier P, Boyle P, Gandini S: Cutaneous melanoma attributable to sunbed use: systematic review and meta-analysis. BMJ 2012; 345: e4757 CrossRef MEDLINE PubMed Central|
|3.||Burgard B, Schöpe J, Holzschuh I, et al.: Solarium use and risk for malignant melanoma: meta-analysis and evidence-based medicine systematic review. Anticancer Res 2018; 38: 1187–99 MEDLINE|
|4.||Colantonio S, Bracken MB, Beecker J: The association of indoor tanning and melanoma in adults: systematic review and meta-analysis. J Am Acad Dermatol 2014; 70: 847–57.e1–18.|