1. International Epidemiology Institute, Rockville, MD, USA;
2. EpidStat Institute, Ann Arbor, MI, USA;
3. Center for Epidemiologic Research, Oak Ridge Associated Universities, Oak Ridge, TN, USA;
4. National Council on Radiation Protection and Measurements, Bethesda, MD, USA;
5. Department of Medicine, Division of Epidemiology, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA