1. Department of Internal Medicine, Division of Epidemiology, University of Utah School of Medicine, Salt Lake City, UT, USA
2. Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
3. Study Design and Biostatistics Center, University of Utah, Salt Lake City, UT, USA
4. Department of Family and Preventive Medicine, University of Utah School of Medicine, Salt Lake City, UT, USA
5. Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
6. Department of Neurosurgery, Clinical Neurosciences Center, University of Utah School of Medicine, Salt Lake City, UT, USA