1. Department of Family Medicine, International St. Mary's Hospital, Catholic Kwandong University College of Medicine, Incheon 404-834, Korea.
2. ENZYCHEM Lifesciences, Daejeon 305-732, Korea.
3. Biomedical Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Korea.
4. Institute for Geriatric Medicine, Yonsei Woori Geriatric Hospital, Goyang 412-802, Korea.