1. Section of Epidemiology, Department of Public Health, University of Copenhagen , Øster Farimagsgade 5, DK-1353 Copenhagen , Denmark
2. Department of Epidemiology Research, Statens Serum Institut , Artillerivej 5, DK-2300 Copenhagen , Denmark
3. Department of Cardiology, Bispebjerg-Frederiksberg University Hospital , Bispebjerg Bakke 23, DK-2400 Copenhagen , Denmark