1. Cooperative Studies Program Epidemiology Center, Durham VA Medical Center, Durham, NC, USA
2. Sanford School of Public Policy, Duke University, Durham, NC, USA
3. Carolina Population Center, University of North Carolina, Chapel Hill, NC, USA
4. Duke Molecular Physiology Institute and Department of Biostatistics and Bioinformatics, Duke University, Durham, NC, USA
5. Division of Human Genetics, Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
6. Veteran Affairs Connecticut Healthcare System, West Haven, CT, USA