Chin-Hsiao Tseng1,2,3. 1. Department of Internal Medicine, National Taiwan University College of Medicine, Taipei, Taiwan ccktsh@ms6.hinet.net. 2. Division of Endocrinology and Metabolism, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan. 3. Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Taiwan.