Table 2.

Quality assessment of the quantitative studies

Reference	A Selection bias	B Study design	C Confounder	D Binding	E Data collection	F Withdrawals and drop-outs
Lowery et al., 2014 [41]	+	+	+	+	+	+
McCurry et al., 2010 [42]	+	+	+	+	+	+/−
Rantakokko et al., 2017 [43]	+	+	+	+	+	+
Van Uffelen et al., 2009 [44]	+	+	+	+	+	+/−

+ strong; +/− moderate; − weak