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.
The error bars indicate 95% CIs. ECG indicates electrocardiography.
aDefined as permanent use of a cane or wheelchair.
