Department of Family Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea. Department of Family Medicine, Jeju National University Hospital, Jeju, South Korea. Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea. Department of Internal Medicine, Konkuk University School of Medicine, Konkuk University Medical Center, Seoul, South Korea. Department of Family Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea. Department of Family Medicine, College of Medicine, Hanyang University, Myongji Hospital, Goyang, South Korea. Daejeon Endo Internal Medicine Clinic, Daejeon, South Korea. Department of Family Medicine, Obesity and Metabolic Disease Center, Seongnam Central Hospital, Seongnam, South Korea. Department of Family Medicine, CHAUM Medical Check-Up Center, CHA Bundang Medical Center, CHA University, Seongnam, South Korea. Department of Family Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, South Korea. Department of Endocrinology and Metabolism, Kyung Hee University College of Medicine, Kyung Hee University Hospital, Seoul, South Korea. Department of Internal Medicine, Kosin University College of Medicine, Busan, South Korea. Department of Internal Medicine, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin, South Korea. Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea. limsoo@snu.ac.kr.