Institutional Review Board Statement
MAY, POLAND
The study was conducted according to the guidelines of the Declaration of Helsinki and was approved by the Bioethics Committee of the Poznan University of Medical Sciences in Poland (protocol code: 606/12, date of approval: 14 June 2012; protocol code: 453/13, date of approval: 9 May 2013; protocol code: 358/14, date of approval: 3 April 2014; protocol code: 398/15, date of approval: 9 April 2015).