Ethical approval was granted from the Ethics Committee of Stockholm.

Ethical approval was not sought as the data were already publicly available online. We checked the robustness of our findings The aim of this study was twofold. This systematic review and meta-analysis includes previously published observational studies. This indicated there was no requirement for proceeding to a full formal ethics and data protection review by the Usher Research Ethics Group. No overall prospective analysis plan was used. Complete case analyses were used. Study approval was received from Institutional Review Boards (IRBs) of the primary research institution These findings must be interpreted in light of several limitations We excluded those with missing data for the primary exposure The data analysis had been planned in advance of the data gathering Data for the NHIS analyses were weighted using the final person weights Consistent with those of other studies, our findings show that This study is subject to certain limitations. Reductions in indoor tanning could be attributed to several factors.