1. Department of Family and Community Medicine, Northeast Ohio Medical University, Rootstown, Ohio.
2. College of Public Health, Kent State University, Kent, Ohio.
3. Epidmiology and Biostatistics, Case Western Reserve University School of Medicine, Center for Health Care Research and Policy, Case Western Reserve University and The MetroHealth System, Cleveland, Ohio.
4. Department of Community and Family Medicine, Duke University School of Medicine, Durham, North Carolina.