2.4 Screening process
The screening process was conducted by two authors independently. After the studies were identified from search strategy, the studies were transferred into EndnoteTM to check for duplication and the studies were removed accordingly. The initial screening was conducted first on study title and abstract. In the second level screening, these articles were then checked within the full text to make sure of their relevancy and eligibility. Any disagreements among reviewers were resolved by discussion and reflection. Finally, the reference lists from the selected articles were reviewed to identify any other relevant trials.