1. Department of Family and Community Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
2. Division of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
3. National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
4. Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
5. School of Nursing, University of Pennsylvania, Philadelphia, Pennsylvania, USA
6. School of Public Health, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey, USA