1. Division of Biostatistics; Institute of Environmental Medicine; Karolinska Institutet; Stockholm Sweden
2. Department of Health Promotion; Education, and Behavior, Arnold School of Public Health University of South Carolina; South Carolina USA
3. Department of Exercise Science; Arnold School of Public Health University of South Carolina; South Carolina USA
4. Department of Epidemiology and Biostatistics; Arnold School of Public Health University of South Carolina; South Carolina USA
5. Greenville Health System; Greenville South Carolina USA
6. Department of Epidemiology; University of Iowa; Iowa USA