Funding for this research was provided by:
Ministry of Science, Research and Arts, state of Baden-Wuerttemberg, Germany
Article History
First Online: 22 October 2018
Compliance with Ethical Standards
:
: The authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The study was approved by the ethics committee of Ulm University for the baseline (312/08) and the follow-up assessment (50/12).
: Informed consent was obtained from all individual participants included in the study.