“…The 13 included studies were published from 1987 to 2019, including three RCTs (Baum et al, 2007;Eriksen et al, 2007;de Sousa et al, 2019), three NRCTs (Opitz et al, 2014a(Opitz et al, , 2015Støa et al, 2017), and seven case-control studies (Schneider et al, 1987;Dela et al, 1995;Holton et al, 2003;Juel et al, 2004;Michishita et al, 2008;Mogensen et al, 2009;Scheede-Bergdahl et al, 2014). Three studies (Mogensen et al, 2009;Opitz et al, 2015;Støa et al, 2017) were assessed as "good" quality, nine studies (Schneider et al, 1987;Dela et al, 1995;Holton et al, 2003;Juel et al, 2004;Baum et al, 2007;Eriksen et al, 2007;Michishita et al, 2008;Opitz et al, 2014a;de Sousa et al, 2019) were of "fair" quality, and one study (Scheede-Bergdahl et al, 2014) was rated with "poor" quality. The detailed quality assessment of studies can be found in Supplementary Table 4.…”