1. aDepartment of Chronic Disease and Health Promotion, World Health Organization, 20 avenue Appia, CH-1211, Geneva 27, Switzerland.
2. bDepartment of Neurology, University of California, San Francisco, United States of America.
3. cNational Center for Chronic and Noncommunicable Disease Control and Prevention, Beijing, China.
4. dCollege of Medicine, University of Ibadan, Ibadan, Nigeria.