“…The search identified 7,205 studies (see Figure S1). A total of 21 studies (Abrahamsen et al, 2014(Abrahamsen et al, , 2016Chen et al, 2002;Dejong et al, 2009;Fiorini et al, 2013;Galizia et al, 2018;Gustavson et al, 2019;Herfjord et al, 2014;Hong et al, 2019;Jette et al, 2004;Jung et al, 2016;Lawler et al, 2019;Lenze et al, 2012Lenze et al, , 2019Leung et al, 2016;Mallinson et al, 2014;Millar et al, 2017;Morita et al, 2018;O'Brien & Zhang, 2018;Parker et al, 2015;Zhang et al, 2019) enrolling 1,206,769 participants were included. Characteristics of included studies are summarised in Table S1 (Appendix S1).…”