The effects of folic acid supplementation on endothelial function in adults: a systematic review and dose-response meta-analysis of randomized controlled trials

Table 2 Quality assessment

Studies	Random sequence generation	Allocation concealment	Selective reporting	Other sources of bias	Blinding (participants and personnel)	Blinding (outcome assessment)	Incomplete outcome data	Overall risk of bias
Woo et al. 1999 [32]	U	H	H	H	L	U	L	H
Bellamy et al. 1999 [43]	U	H	H	H	L	U	L	H
Thambyrajah et al. 2000 [33]	L	H	H	H	L	U	L	H
Title et al. 2000 [30]	L	H	H	H	L	U	L	H
Doshi et al. 2001 [44]	L	H	H	H	L	U	L	H
Pullin et al. 2001 [45]	L	L	H	H	L	U	L	M
Thambyrajah et al. 2001 [34]	L	H	H	H	L	U	L	H
Doshi et al. 2002 [46]	L	H	H	H	L	U	L	H
Doshi et al. 2003 [47]	L	H	H	H	L	U	L	H
Spoelstra-de Man et al. 2004 [36]	L	L	H	H	L	U	L	M
Doshi et al. 2004 [48]	L	H	H	H	L	U	L	H
Lekakis et al. 2004 [29]	L	H	H	H	L	U	L	H
Woodman et al. 2004 [35]	L	H	H	H	L	U	L	H
Durga et al. 2005 [49]	L	H	H	H	L	U	L	H
Moat et al. 2006 [50]	L	H	H	H	L	U	L	H
Title et al. 2006 [31]	L	H	H	H	L	U	L	H
Moens et al. 2007 [51]	L	H	H	H	L	U	L	H
Shirodaria et al. 2007 [52]	L	H	H	H	L	U	L	H
Woo et al. 2008 [53]	L	H	H	H	L	U	L	H
Palomba et al. 2010 [54]	L	H	H	H	L	U	L	H
Hashemi et al. 2016 [55]	L	L	H	H	L	L	L	M

Overall risk of bias: L, low-risk of bias (H < 2); M: moderate-risk of bias (H = 2); H: high-risk of bias (H > 2)
Abreviations: L low-risk of bias, U unclear-risk of bias, H high-risk of bias

ISSN: 1475-2891