Although medical restraints, used properly, can help prevent injury, they can also be dangerous. The United States Food and Drug Administration (FDA) estimated in 1992 that improper use of restraints results in at least 100 deaths each year, most by strangulation. FDA also noted reports of injuries — including broken bones and burns — caused by the improper use of restraints. Medical restraints in psychiatric hospitals in Japan are sometimes kept on patients for weeks and months, and they are thought to have caused several deaths due to deep vein thrombosis and pulmonary embolism. More information about Japanese use of restraints is described in the page on physical restraints.