1. Department of Preventative Medicine, School of Medicine, Kyungpook National University, Daegu, Korea
2. Department of Laboratory Medicine and Pathology, School of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
3. Organic Analytical Toxicology Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
4. Division of Epidemiology, School of Public Health, University of Minnesota, Minneapolis, Minnesota, USA
5. Department of Nutrition, University of Oslo, Oslo, Norway