Data extraction

Two independent reviewers extracted the necessary data from each study using a predefined Excel spreadsheet. The spread sheet was prepared using the standardized JBI data extraction tools, where specific information regarding the participants, study procedures (design), exposure, outcome, cell values, and effect size estimates were captured. Further contacts and requests for details from the authors of the primary studies were made for missing information and additional data for clarification as deemed appropriate. Any differences between the review authors were settled through conversation or consultation with a third independent party.