1. Biodemography of Aging Research Unit, Social Science Research Institute Duke University Durham North Carolina USA
2. Division of Statistical Genomics, Department of Genetics Washington University School of Medicine St Louis Missouri USA
3. Gertrude H. Sergievsky Center Columbia University Irving Medical Center New York New York USA
4. Unit of Epidemiology, Biostatistics and Biodemography, Department of Public Health Southern Denmark University Odense Denmark