2.2. Searching, selection of studies and data extraction

PubMed, Embase and Cochrane Library were searched from inception to October 2021. Two authors (S-RJ and T-HK) conducted selection of the studies independently, and discussed the results until an agreement was reached. After selection of the studies, data extraction was conducted by two authors (S-RJ and T-HK) independently with a predefined extraction form, and disagreement was solved through discussion. Data including intervention types, review objectives, population, number of included studies, summary effect estimates and overall risk of bias were extracted from the original SRs. Search strategies were modified according to the specific features of the electronic databases (Supplementary file 1).