- Correspondence to Dr Dale P Sandler, Epidemiology Branch/Chronic Disease Epidemiology Group, National Institute of Environmental Health Sciences, P.O. Box 12233, MD A3-05, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA;
- Received November 10, 2014
- Revised May 2, 2015
- Accepted June 22, 2015
- First published July 15, 2015.
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- Data supplement 1 - Online supplement
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