1. Section for Epidemiology, Department of Public Health, University of Aarhus, Aarhus, Denmark.
2. Section for Biostatistics, Department of Public Health, University of Aarhus, Aarhus, Denmark.
3. Department of Paediatrics, University of Aarhus, Aarhus, Denmark.
4. Section for General Practice/Family Medicine, Department of Public Health, University of Aarhus, Aarhus, Denmark.