| Study | Reason for exclusion |
|---|---|
| Aoki 1995 | Observational, not randomized, no control group. |
| Falk 1992 | Interventional but not randomized, no control group. |
| Fitzhugh 2005 | Observational, not randomized, no control group. |
| McKie 2007 | Observational, not randomized, no control group. |
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.