Received: 8 March 2021
Accepted: 23 September 2021
First Online: 12 October 2021
: The regional ethics committee (EC,Canton Zurich) approved the study on 4<sup>th</sup> May 2015 (<i>PB_2016-01523</i>). Data collection was conducted in accordance with Good Clinical Practice protocols and the Declaration of Helsinki principles. The COPD participants received written and oral information about the study. Written informed consent was obtained from all participants prior to baseline measurement.
: Not applicable.
: All authors declare that they have no competing interests.