1. Department of Women and Child Health, Karolinska Hospital, Stockholm, Sweden, Lotti.helströ
2. Department of Women and Child Health, Karolinska Hospital, Stockholm, Sweden
3. Department of Medical Epidemiology, Karolinska Institute, Stockholm, Sweden, Unit of Clinical Epidemiology, Department of Medicine, Karolinska Hospital, Stockholm, Sweden
4. Department of Medical Epidemiology, Karolinska Institute, Stockholm, Sweden
5. Department of Medical Epidemiology, Karolinska Institute, Stockholm, Sweden, Unit of Clinical Epidemiology, Department of Medicine, Karolinska Hospital, Stockholm, Sweden, Department of Epidemiology, Harvard School of Public Health, Boston, USA