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.
Martinson M, Berridge C.Martinson M, et al. Among authors: berridge c.Gerontologist. 2015 Feb;55(1):58-69. doi: 10.1093/geront/gnu037. Epub 2014 May 9.Gerontologist. 2015.PMID: 24814830Free PMC article.Review.