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.
Hou N, Popkin BM, Jacobs DR Jr, Song Y, Guilkey DK, He K, Lewis CE, Gordon-Larsen P.Hou N, et al.Prev Med. 2011 May;52(5):365-9. doi: 10.1016/j.ypmed.2011.02.007. Epub 2011 Feb 19.Prev Med. 2011.PMID: 21338621Free PMC article.