1. Department of Endocrinology, Morbid Obesity and Preventive Medicine; Oslo University Hospital; Oslo Norway
2. Department of General Practice; Institute of Health and Society; Faculty of Medicine; University of Oslo; Oslo Norway
3. Oslo Center for Biostatistics and Epidemiology; Oslo University Hospital; Oslo Norway
4. Institute of Clinical Medicine; Faculty of Medicine; University of Oslo; Oslo Norway
5. Norwegian Institute of Public Health; Oslo Norway
6. Department for Women's and Children's Health; Norwegian Resource Centre for Women's Health; Oslo University Hospital; Oslo Norway
7. Faculty of Health Sciences; Oslo and Akershus University College of Applied Sciences; Oslo Norway
8. Norwegian Resource Centre for Breastfeeding; Oslo University Hospital; Oslo Norway