Ethical standards
The authors assert that all procedures contributing to this work comply with the ethical standards of the relevant national and institutional guidelines on human experimentation and with the Helsinki Declaration of 1975, as revised in 2008. Ethics approval was obtained from the Regional Ethics Review Board of Stockholm. Reference: 2016/1013-31/4, Protocol number: 2016/4:6. Written informed consent was obtained from all subjects/patients prior to participating in the study.