Study Year of
publication 		Random sequence generation Allocation concealment Blinding of
participants and personnel 		Blinding of
outcome assessment 		Incomplete outcome data Selective reporting Other bias
Siebert et al. [33] 2015 High High Low High Low Low Low
Lazarovici et al. [34] 2010 High High Unclear High Low Low Low
Shabestari et al. [36] 2010 High High Unclear High Low Low High
Bell and Bell [37] 2008 High High Unclear High Low Low Low
Fugazzotto et al. [38] 2007 High High Unclear High Low Low High
Jeffcoat [39] 2006 High Low Low High Low Low Low