All GSHS surveys were approved in each country by both a national government administrative body and an institutional review board or ethics committee

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. SUDAAN software, version 10.1 (RTI International), which accounts for weighted data and the complex sample design Student consent was assumed with the completion of the questionnaire. The IRB at the University of Massachusetts Medical School reviewed the protocol and exempted it from the full committee review