Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Phases of article selection and retrieval at each phase.
| Phase | Description | Articles included for review, N |
| 1 | Total number of articles from all digital databases | 8144 |
| 2 | Snowball sampling | 8181 |
| 3 | Removal of duplicates | 1514 |
| 4 | Exclusion based on language | 1442 |
| 5 | Exclusion based on access and type of study (eg, reviews and survey papers) | 892 |
| 6 | Exclusion based on title, abstract, and keywords | 278 |
| 7 | Exclusion based on full text and nonprimary study | 80 |
