1. Clinical Epidemiology Unit; Department of Medicine Solna; Karolinska Institute; Stockholm Sweden
2. Faculty of Medicine; Golestan University of Medical Sciences; Gorgan Iran
3. Faculty of Medicine; Mazandaran University of Medical Sciences; Sari Iran
4. Clinical Epidemiology and Biostatistics; Örebro University Hospital & Örebro University; Örebro Sweden
5. Research Department of Epidemiology and Public Health; University College London; London UK
6. Division of Obstetrics and Gynecology; Department of Women's and Children's Health; Karolinska University Hospital and Institute; Stockholm Sweden
7. Department of Women's and Children's Health; Uppsala University; Uppsala Sweden
8. Clinical Epidemiology Unit & Center for Pharmacoepidemiology; Department of Medicine; Solna, Karolinska Institute; Stockholm Sweden