Correction to: Journal of Exposure Science and Environmental Epidemiology (2010) 20, 615–624; doi:10.1038/jes.2010.7; published online 17 March 2010

After the above article was published online, one of the authors noticed that the following disclaimer had been omitted from the article:

“The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.”