1. Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, Washington, USA.
2. Department of Epidemiology, UNC Gillings School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
3. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
4. Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
5. Department of American Ethnic Studies, University of Washington, Seattle, Washington, USA.