1. Department of Family Medicine, Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada.
2. Cedars-Sinai Medical Center, Los Angeles, California.
3. Department of General Internal Medicine, University of California, Los Angeles, California.
4. Department of Family Medicine, David Geffen School of Medicine, University of California, Los Angeles, California.