1. Department of Research & Evaluation, Kaiser Permanente Southern California, Pasadena, California, USA.
2. Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena, California, USA.
3. Cousins Center for Psychoneuroimmunology, UCLA Semel Institute for Neuroscience and Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA.