Assessment of Risk of Bias
We assessed risk of bias of the studies using the risk of
bias tool of the Cochrane collaboration (Higgins, Altman,
Gøtzsche et al., 2011; Higgins, Altman, & Sterne, 2011). The
tool consists of six domains: selection bias, performance
bias, detection bias, attrition bias, reporting bias, and other
bias (Higgins, Altman, Gøtzsche, et al., 2011; Higgins,
Altman, & Sterne, 2011). Two authors (M.J. and A.C.)
independently rated the risk of bias in the format as low,