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.
Rivina L, Schiestl R.Rivina L, et al.Int J Environ Res Public Health. 2012 Dec 27;10(1):107-43. doi: 10.3390/ijerph10010107.Int J Environ Res Public Health. 2012.PMID: 23271302Free PMC article.Review.