1. Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine , Sapporo, Japan
2. Department of Cardiovascular Surgery, Sapporo Medical University School of Medicine , Sapporo, Japan
3. Department of Public Health, Sapporo Medical University School of Medicine , Sapporo, Japan
4. Department of Health Checkup and Promotion, Keijinkai Maruyama Clinic , Sapporo, Japan