AUTHOR CONTRIBUTIONS
All the listed authors contributed significantly to this study. Vernon A. Chuabio and Ron Michael L. Castillo prepared the study protocol, searched the literature, pooled the retrieved data, synthesized results using statistical software, and drafted the article. Jereel R. Sahagun and Rey Jaime M. Tan provided revisions to the study with respect to methods, content, interpretation of results, as well as gave final approval for this study.