An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Kanner RE, Connett JE, Williams DE, Buist AS.Kanner RE, et al. Among authors: buist as.Am J Med. 1999 Apr;106(4):410-6. doi: 10.1016/s0002-9343(99)00056-x.Am J Med. 1999.PMID: 10225243Clinical Trial.