Table 1.

Bias risk of different aspects for the selected studies.

Study	Randomized (Selection Bias)	Blinding of Participants (Performance Bias)	Blinding of Outcome Assessment (Detection Bias)
Nieman et al., 2013 [32]	+	+	+
Shanely et al., 2014 [33]	+	+	+
Parsaie et al., 2019 [34]	+	+	+
Ashtary-Larky et al., 2020 [35]	+	+	+
Pilch et al., 2020 [36]	+	−	−
Żebrowska et al., 2020 [37]	−	+	+

(+) indicates low bias risk and (−) indicates high bias risk.