Ethics approval and consent to participate
All participants were informed about the course of the study and possible risks. All participating children provided written informed assent to take part in the study. Parents provided informed consent for their children under 18 years and for their own participation in the study. The study was approved by the Ethics Committee of the Medical Faculty at the University of the LMU Munich (Study ID: 3–14). All methods were conducted in accordance with the Declaration of Helsinki.