1. Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA
2. Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA
3. Texas Department of State Health Services, Austin, Texas, USA
4. School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA
5. Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts, USA
6. Medical Institute, Austin, Texas, USA