1. National Center for Complementary and Integrative Health (NCCIH), National Institutes of Health, Bethesda, MD, USA.
2. National Center for Health Statistics, Hyattsville, MD, USA.
3. Department of Preventive Medicine and Biostatistics, School of Medicine, Uniformed Services University, Bethesda, MD, USA.
4. Kelly Government Solutions, Rockville, MD, USA.