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.
Parr N, Li J, Tickle L.Parr N, et al.Popul Stud (Camb). 2016 Jul;70(2):181-200. doi: 10.1080/00324728.2016.1190029. Epub 2016 Jun 10.Popul Stud (Camb). 2016.PMID: 27282412
Weerasinghe DP, Yusuf F, Parr NJ.Weerasinghe DP, et al.Int J Environ Res Public Health. 2009 Jan;6(1):232-245. doi: 10.3390/ijerph6010245. Epub 2009 Jan 12.Int J Environ Res Public Health. 2009.PMID: 19440280Free PMC article.