1. Department of Clinical Science and Education, Karolinska Institute, Södersjukhuset , Stockholm , Sweden
2. Stockholm Hernia Center , Stockholm , Sweden
3. Women's Health Department, Hela Kvinnans Klinik , Stockholm , Sweden
4. Department of Surgery, Södersjukhuset , Stockholm , Sweden
5. Unit of Nutritional Epidemiology, Karolinska Institute, Institute of Environmental Medicine , Stockholm , Sweden