Methodological quality assessment of review studies

As suggested by the PRISMA explanation and evaluation statement (Liberati et al., 2009), a methodological quality assessment or risk of bias for each study was conducted utilizing a modified augmented Jadad scale (Sarris and Byrne, 2011). The original Jadad scale was based on the quality factors of randomization, blinding, and reported withdrawals, while the modified version also assesses methodological factors such as utilization of a control, data reporting, exclusion criteria, and intervention used to provide a quality total out of 10. Evaluation of studies was performed by one author and reviewed by the second author for agreement. Studies were not excluded on the basis of their bias scores but are presented to empirically rate study quality.