Fig 1. Prisma flow diagram.

Fig 1 shows the process of selecting relevant studies from 41138 records. After removing 3476 duplicates, 37662 records were screened; 37602 of the records were excluded based on the title and abstract. Full texts of 60 potential eligible articles were retrieved and reviewed for inclusion. Of the 60 records, 17 studies met our inclusion criteria and 43 studies were excluded.