1. Division of General Internal Medicine; Department of Medicine; St. Luke's International Hospital; Tokyo Japan
2. Center for Clinical Epidemiology; St. Luke's International Hospital; Tokyo Japan
3. Fujita Health University; Toyoake Japan
4. Division of Rheumatology; JR Tokyo General Hospital; Tokyo Japan
5. Department of Epidemiology for Community Health and Medicine; Kyoto Prefectural University of Medicine; Kyoto Japan