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.
Oliver TR.Oliver TR.Annu Rev Public Health. 2006;27:195-233. doi: 10.1146/annurev.publhealth.25.101802.123126.Annu Rev Public Health. 2006.PMID: 16533115Review.