1. Population Health Research Institute, St. George's, University of London, Cranmer Terrace, London, United Kingdom
2. Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, Massachusetts, United States
3. Bristol Medical School: Population Health Sciences, University of Bristol, Bristol, United Kingdom
4. National Research and Applied Medicine Mother and Child Centre, Minsk, Republic of Belarus
5. Departments of Pediatrics and of Epidemiology, Biostatistics and Occupational Health, McGill University Faculty of Medicine, Montreal, Canada
6. University Hospitals Bristol NHS Foundation Trust and University of Bristol National Institute for Health Research Bristol Biomedical Research Centre, Bristol, United Kingdom
7. Medical Research Council Integrative Epidemiology Unit at the University of Bristol, Bristol, United Kingdom