1. Department of Clinical Biochemistry and Immunology, Statens Serum Institut, Copenhagen, Denmark.
2. NANEA, Department of Epidemiology, Institute of Public Health, University of Aarhus, Aarhus, Denmark.
3. Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark.
4. Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia.