1 Department of Medicine, University of California, San Francisco, San Francisco, California; Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California. Electronic address: Judy.hahn@ucsf.edu.
2 School of Nursing, Vanderbilt University, Nashville, Tennessee.
3 Department of Kinesiology, University of Texas at Arlington, Arlington, Texas.
4 General Internal Medicine, Yale School of Medicine, New Haven, Connecticut.