1. Massachusetts Veterans Epidemiology Research and information Center (MAVERIC), Veterans Affairs Boston Healthcare System, Department of Veterans Affairs Office of Research and Development–-Cooperative Studies Program, Washington DC, USA.
2. VA Ann Arbor Healthcare System, the University of Michigan Comprehensive Cancer Center, Ann Arbor, MI, USA.
3. Cedar Associates, Menlo Park, CA, USA.
4. Department of Medicine, Stanford University, Stanford, CA, USA.
5. Department of Biomedical Data Science, Stanford University, Stanford, CA, USA.
6. Department of Statistics, Stanford University, Stanford, CA, USA.