Contribution to Authorship
SL, SR and MLW designed and planned the study. SL, SR and MLW performed the search. SL, SR, YJ, DN, and MLW independently screened and selected eligible studies, and completed data extraction, verifying each other’s work. SL, SR, YJ and MLW contributed to the interpretation of the data and the writing of the article. All authors reviewed and approved the final version of the manuscript and accepted responsibility for the paper as published.