Received: 6 May 2019
Accepted: 23 October 2019
First Online: 6 November 2019
Ethics approval and consent to participate
: This study was deemed exempt from medical ethical approval by the University Medical Center Groningen institutional Medical Ethical Committee.
: Not applicable.
: The authors declare, that they have no relevant conflict of interest regarding this manuscript. The authors report to have received funding from the Nutricia Research Foundation, GSK, TEVA the Netherlands, UBBO EMMIUS Foundation, TETRI Foundation, Lung Foundation of the Netherlands, which had no relation to the submitted work.