1. Department of Family and Preventive Medicine University of Arkansas for Medical Sciences Little Rock Arkansas
2. Occupational and Environmental Epidemiology Branch Division of Cancer Epidemiology and Genetics National Cancer InstituteNational Institutes of Health Rockville Maryland
3. Department of Population Medicine Harvard Medical School and Harvard Pilgrim Health Care Institute Boston Massachusetts
4. Department of Environmental Health Harvard T.H. Chan School of Public Health Boston Massachusetts
5. Radiation Epidemiology Branch Division of Cancer Epidemiology and Genetics National Cancer Institute Bethesda Maryland
6. Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health The University of Texas Health Science Center at Houston Houston Texas