1. Departments of Epidemiology
2. Center of Disease Prevention and Control of Jiexiu, Shanxi, China
3. General Practice, Institute of Public Health, University of Aarhus, Aarhus, Denmark
4. Department of Neurology and Department of Clinical Pharmacology, Aarhus University Hospital, Aarhus, Denmark
5. Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania
6. Department of Epidemiology, School of Public Health, University of California at Los Angeles, Los Angeles, California