1. College of Medicine, Nursing and Health Sciences, School of Medicine, National University of Ireland , Galway H91TK33 , Ireland
2. Department of Epidemiology, Harvard T. H. Chan School of Public Health , Boston, MA 02115 , USA
3. Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine , London KT12EE , UK
4. Division of Hematology, Brigham & Women’s Hospital, Harvard Medical School , Boston, MA 02115 , USA
5. Department of Obstetrics and Gynecology, Medizinische Universitaet Graz , Graz A8036 , Austria
6. Department of Clinical Biochemistry, Saolta University Health Care Group (SUHCG), Galway University Hospitals , Galway H91YR71 , Ireland