1. Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
2. Health Care Center, Nishi-Nippon Railroad Co., Ltd., Fukuoka, Japan
3. Center for Cohort Studies, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
4. Division of Internal Medicine, Fukuoka Dental College, Fukuoka, Japan