Center for Epidemiology and Environmental Health, Consultants in Epidemiology and Occupational Health (CEOH), Washington, DC 20016, USA. Steve@CEOH.com. Department of Health Policy and Management, School of Public Health, Johns Hopkins University-Bloomberg, Baltimore, MA 21205, USA. Steve@CEOH.com. Department of Pediatrics, School of Medicine, Georgetown University, Washington, DC 20057, USA. Steve@CEOH.com. Center for Epidemiology and Environmental Health, Consultants in Epidemiology and Occupational Health (CEOH), Washington, DC 20016, USA. Hamid@CEOH.com. Department of Epidemiology and Biostatistics, School of Public Health, George Washington University-Milken Institute, Washington, DC 20052, USA. Hamid@CEOH.com. Center for Epidemiology and Environmental Health, Consultants in Epidemiology and Occupational Health (CEOH), Washington, DC 20016, USA. Elisabeth.Dissen@gmail.com. Department of Pathology, School of Medicine, Johns Hopkins University, Baltimore, MA 28217, USA. JLi42@JHMI.edu. Department of Biostatistics, Bioinformatics, and Biomathematics, School of Medicine, Georgetown University, Washington, DC 20057, USA. JA1030@Georgetown.edu.