[1] Univ Bern, Inst Social & Prevent Med, Bern, Switzerland
[2] Univ Bern, Grad Sch Hlth Sci, Bern, Switzerland
[3] Univ Childrens Hosp Bern, Dept Resp Med, Bern, Switzerland
[4] Univ Childrens Hosp Zurich, Dept Resp Med, Zurich, Switzerland
[5] Univ Zurich, Childrens Res Ctr, Zurich, Switzerland
[6] Univ Basel, Univ Childrens Hosp Basel UKBB, Basel, Switzerland
[7] Cantonal Hosp Luzern, Childrens Hosp, Div Paediat Pulmonol, Luzern, Switzerland