1. Department of Health, Behavior and Society Johns Hopkins Bloomberg School of Public Health Baltimore Maryland USA
2. Department of Biostatistics Johns Hopkins Bloomberg School of Public Health Baltimore Maryland USA
3. Department of Community and Family Medicine Duke University Medical Center Durham North Carolina USA
4. Division of Biostatistics Department of Public Health Sciences Medical University of South Carolina Charleston South Carolina USA
5. Department of Exercise Science Arnold School of Public Health University of South Carolina Columbia South Carolina USA