Table 2.

Risk of bias items for each included non-randomized control trial study

	Bias due to confounding	Bias in the selection of participants for the study	Bias in classification of interventions	Bias due to deviations from intended intervention	Bias due to missing data	Bias in measurement of outcomes	Bias in the selection of the reported results	Overall
Espie et al. [11]	Serious	Low	Low	Serious	Critical	Critical	Serious	Critical
Burton et al. [17]	Serious	Low	Low	Serious	Critical	Critical	Serious	Critical
Mills et al. [32]	Serious	Low	Low	Serious	Moderate	Moderate	Serious	Serious