1. Institute for Health Research, Kaiser Permanente Colorado, Denver, Colorado
2. Colorado Permanente Medical Group, Denver, Colorado
3. Division of General Internal Medicine, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
4. National Addiction Centre, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
5. Department of Epidemiology, Colorado School of Public Health, Aurora, Colorado, USA