Table 1.

Quality assessment results for the included studies

Authors (year)	Selection bias	Study design	Confounders	Blinding	Data collection methods	Withdrawal and dropouts	Global rating
Wright et al 44 (2017)	Moderate	Strong	Weak	Moderate	Strong	Moderate	Moderate
Lee et al 45 (2016)	Strong	Strong	Strong	Moderate	Strong	Strong	Strong
Bunner et al 41 (2015)	Strong	Strong	Strong	Moderate	Strong	Strong	Strong
Soare et al 43 (2014)	Strong	Strong	Strong	Moderate	Strong	Strong	Strong
Mishra et al 39 (2013)	Moderate	Strong	Strong	Moderate	Strong	Moderate	Strong
Kahleova et al 35 (2013)	Strong	Strong	Strong	Moderate	Strong	Strong	Strong
Kahleova et al 36 (2011)	Strong	Strong	Strong	Moderate	Strong	Strong	Strong
Ferdowsian et al 40 (2010)	Moderate	Strong	Strong	Moderate	Strong	Strong	Strong
Barnard et al 37 (2009b)	Strong	Strong	Strong	Moderate	Strong	Strong	Strong
Barnard et al 38 (2009a)	Strong	Strong	Strong	Moderate	Strong	Strong	Strong
Nicholson et al 42 (1999)	Strong	Strong	Strong	Moderate	Strong	Moderate	Strong