1. Department of Public Health; Norwegian University of Science and Technology; Trondheim Norway
2. Department of Endocrinology; Trondheim University Hospital; Trondheim Norway
3. Department of Obstetrics and Gynecology; Akershus University Hospital and Institute of Clinical Medicine; University of Oslo; Lørenskog Norway
4. Division of Mental Health; Norwegian Institute of Public Health; Oslo Norway
5. Department of Epidemiology; Harvard School of Public Health; Boston Massachusetts USA