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.
Luo Y, Waite LJ.Luo Y, et al.J Gerontol B Psychol Sci Soc Sci. 2014 Jul;69(4):633-45. doi: 10.1093/geronb/gbu007. Epub 2014 Feb 18.J Gerontol B Psychol Sci Soc Sci. 2014.PMID: 24550354Free PMC article.