Contribution to authorship
All authors contributed to the study protocol. The literature search was performed by A.H, N.T and B.H.R. Literature screening, data extraction, were performed by D.P, A.H, N.T and B.H.R. Risk of bias evaluation was performed by A.H and N.T.
A.H and B.H.R conducted the analyses. The draft of the manuscript was written by A.H, B.H.R and R.R., and all authors commented on earlier versions of the manuscript. All authors read and approved the final manuscript
Disclosure statement: The authors report no conflict of interest.Source of funding: None
Acknowledgments: Not applicable