Author Contributions
All authors substantially conceived and designed concept, structure and design of the review, provided important intellectual input, contributed considerably to the analyses and interpretation of the data and have been involved in re-drafting the manuscript. CV, BB and MJ counter-checked the literature search, BB evaluated the methodology in the reviewed papers. All authors critically revised the manuscript and gave final approval of the version to be published. No honorarium, grant, or other form of payment was given to any of the authors to produce this manuscript.