Table 3.

Results using the risk of bias tool 2

Ref.	D1	D2	D3	D4	D5	Overall
Stahl et al[44], 2017	+	+	+	+	+	+
Burmeister et al[43], 2011	+	+	+	+	+	+
Visser et al[42], 2018	!	+	+	+	+	!
Markar et al[41], 2017	!	+	+	+	+	!
Goense et al[40], 2017	!	+	+	+	+	!
Favi et al[39], 2017	!	+	+	+	+	!
Anderegg et al[35], 2017	!	+	+	+	+	!
Spicer et al[38], 2016	!	+	+	+	+	!
Luc et al[36], 2015	!	+	+	+	+	!
Münch et al[37], 2018	!	+	+	!	+	!

+: Low risk; !: Some concerns; -: High risk. D1: Randomization process; D2: Deviation from the intended interventions; D3: Missing outcome data; D4: Measurement of the outcome; D5: Selection of the reported result.