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.
Koopman C, van Oeffelen AA, Bots ML, Engelfriet PM, Verschuren WM, van Rossem L, van Dis I, Capewell S, Vaartjes I.Koopman C, et al. Among authors: van oeffelen aa, van dis i, van rossem l.BMC Public Health. 2012 Aug 7;12:617. doi: 10.1186/1471-2458-12-617.BMC Public Health. 2012.PMID: 22870916Free PMC article.