Data sources and search strategy
The electronic databases of Pubmed, Embase, Cochrane library, and ClinicalTrails.gov were searched to identify all eligible studies from inception to May 5th, 2020; the search strategy of terms mainly included three parts: atrial fibrillation; anticoagulants or antithrombins or factor Xa inhibitors or dabigatran or DOAC or NOAC or warfarin or vitamin K antagonist*; dementia or Alzheimer disease or cognition disorders or cognitive dysfunction; and their entry terms in MeSH were also used. Reference lists of all included articles and previous meta-analysis articles were manually scanned to supplement the potentially eligible studies. There were no language restrictions. Two authors (Mingjie Lin and Wenqiang Han) independently searched databases and the disagreements were checked by themselves. Full search strategies for all databases are presented in Supplementary Table 1.