1. Division of Geriatrics & Center for Bioethics and Humanities, University of Colorado School of Medicine , Aurora, Colorado , USA
2. Department of Economics, University of Colorado Denver , Denver, Colorado , USA
3. Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania , USA
4. Institute for Social Research, University of Michigan , Ann Arbor, Michigan , USA
5. School of Nursing, Johns Hopkins University , Baltimore, Maryland , USA
6. Department of Mental Health, School of Public Health , Johns Hopkins, Baltimore, Maryland , USA
7. University of Michigan Medical School, University of Michigan , Ann Arbor, Michigan , USA