Author contributions:
Concept/design: Can Öztürk, Robert Schueler
Data analysis/interpretation: Can Öztürk, Robert Schueler, Marcel Weber, Noriaki Tabata, Atsushi Sugiura
Drafting article: Can Öztürk, Robert Schueler, Georg Nickenig
Critical revision of the article: Robert Schueler, Georg Nickenig, Marcel Weber
Statistics: Can Öztürk, Kim Sprengler, Robert Schueler
Data collection: Kim Sprengler, Can Öztürk, Noriaki Tabata, Atsushi Sugiura