1. University of British Columbia, School of Occupational and Environmental Hygiene, Vancouver, British Columbia, Canada
2. GSF–National Research Center for Environment and Health, Institute of Epidemiology, Neuherberg, Germany
3. Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands
4. Department of Pediatrics, Division of Respiratory Medicine, Erasmus Medical Center–Sophia Children’s Hospital, Erasmus University, Rotterdam, the Netherlands
5. Department of Pediatric Respiratory Medicine, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
6. Julius Centre for Health Sciences and Primary Care, University Medical Centre, Utrecht, the Netherlands
7. Centre for Prevention and Health Services Research, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands