Table 1 Methodological quality summary and level of evidence (LoE)

Allaire 1992 [11]

O

O

-

-

+

O

2

Andrieu 2009 [12]

O

O

-

-

O

-

2

Aribogan 2002 [13]

O

O

-

+

O

-

2

Bilgin 2011 [14]

+

O

+

+

O

-

1

Borazan 2010 [15]

+

O

+

O

O

O

1

Brown 2004 [16]

+

O

+

O

+

O

1

Chelly 2011 [17]

+

O

+

+

+

-

1

Fant 2011 [18]

+

O

+

O

+

O

1

Gaitini 1996 [19]

O

O

-

-

O

-

Gottschalk 1998 [20]

O

O

+

+

O

O

1

Groudine 1998 [21]

+

O

+

+

+

O

1

Gupta 20 06 [22]

+

O

+

+

+

-

1

Habib 2008 [23]

O

O

+

+

+

O

1

Habib 20 09 [24]

+

+

+

+

+

-

1

Haythornthwaite 1998 [25]

O

O

-

+

O

O

Heid 20 07 [26]

+

O

+

+

O

-

1

Hohwu 20 06 [27]

O

+

-

-

+

O

1

Hong 2011 [28]

+

O

+

+

+

O

1

Huang 2001 [29]

+

O

+

+

O

O

1

Katz 2004 [30]

+

+

+

+

+

O

1

Liu 1995 [31]

O

O

+

+

O

O

1

Mayson 2000 [32]

+

O

+

+

+

O

1

Mazaris 2008 [33]

O

O

_-

_-

O

O

2

Ormiston 1981 [34]

O

O

+

O

+

-

1

Salonia 20 06 [36]

+

O

-

-

O

O

2

Shir 1994 [37]

O

O

-

+

O

O

2

Snijdelaar 2004a [38]

+

O

+

O

+

O

1

Snijdelaar 2004b [39]

+

O

+

+

+

-

1

Tauzin-Fin 2006 [40]

+

O

+

+

O

O

1

Tauzin-Fin 2007 [41]

+

O

+

+

+

O

1

Tauzin-Fin 2009 [42]

+

O

+

+

+

O

1

Wu 2005 [43]

+

O

+

+

O

O

1

Lauwick 20 09 [44]

+

+

+

O

O

O

1

Hong 20 09 [45]

+

O

-

+

+

-

1

Lee 2011 [46]

O

O

-

+

O

O

Lukasewycz 20 1 0 [47]

+

O

+

+

+

-

1

Larijani 2004 [48]

O

O

+

O

O

-

Weinberg 2014 [49]

+

O

+

+

+

O

1

Fuller 2013 [50]

+

+

O

+

+

+

1

Dirkmann 2015 [55]

+

+

+

+

+

+

1

Nuri-Deniz 2013 [56]

+

O

-

+

+

+

1

Ozbek 2013 [57]

+

-

+

+

O

+

1

Elkassabany 2013 [59]

+

+

+

+

+

+

1

Kristensen 2013 [61]

+

+

+

+

+

+

1

Deniz 2012 [62]

+

-

-

O

+

O

1