1Department of Paediatric Respiratory Medicine, School for Public Health and Primary Health Care (CAPHRI), Maastricht University Medical Centre (MUMC+), Maastricht, The Netherlands
2Department of Methodology and Statistics, CAPHRI, MUMC+, Maastricht, The Netherlands
3Department of Respiratory Medicine, CAPHRI, MUMC+, Maastricht, The Netherlands
4Department of Paediatric Respiratory Medicine, Wilhelmina Children’s Hospital, University Medical Centre Utrecht (UMCU), Utrecht, The Netherlands
5Department of Paediatric Respiratory Medicine, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
© The Author(s) 2018
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