Figure 4. Decades in which treatments have been tested.
Most treatment comparisons have been implemented in the decades of the 1990s and 2000s.
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.