1. Queen's University Belfast; School of Nursing and Midwifery; Medical Biology Centre 97 Lisburn Road Belfast Northern Ireland UK
2. Nuffield Department of Population Health, University of Oxford; National Perinatal Epidemiology Unit; Oxford UK
3. Retired Honorary Professor of Child Health, Queen's University Belfast; 74 Deramore Park South Belfast Northern Ireland UK BT9 5JY
4. University of Alberta; Department of Pediatrics; 8B19 11111 Jasper Avenue Edmonton AB Canada T5K 0L4
5. University of Toronto; Lawrence S Bloomberg Faculty of Nursing; Health Sciences Building 155 College Street Toronto Ontario Canada M5T 2S8
6. Soochow University; Taipei Taiwan
7. The University of Melbourne; Melbourne Australia