1. Cardiovascular Medicine, Nambu Hospital, Okinawa, Japan
2. Department of Preventive Medicine and Public Health, Fukuoka University, Fukuoka, Japan
3. Department of Biostatistics, University of Kentucky, KY, USA
4. Okinawa Heart and Renal Association, Okinawa, Japan
5. Okinawa Health Promotion Foundation, Okinawa, Japan