1. Department of Epidemiology; University of North Carolina; Chapel Hill North Carolina USA
2. Carolina Population Center; University of North Carolina; Chapel Hill North Carolina USA
3. Division of Epidemiology, Department of Preventive Medicine; Northwestern University; Chicago Illinois USA
4. Division of Epidemiology, Department of Family Medicine and Population Health; Virginia Commonwealth University; Richmond Virginia USA
5. Institute for Social Research; University of Michigan; Ann Arbor Michigan USA
6. Department of Sociology; University of Washington; Seattle Washington USA
7. Department of Public Health and Health Sciences; University of Michigan-Flint; Flint Michigan USA