The authors declare they have no competing interests.
All authors made significant contributions and participated sufficiently in the present manuscript. SS, VP, JG, AB and PN were involved in the conception of the study. SS, VP, KC and AB were involved in recruitment, data collection, data (statistical) analysis and were also involved in the writing process and critical analyses. FT and EB were involved in the recruitment process and manuscript review. PN was involved in all aspects of this manuscript. All authors read and approved the final manuscript.
The online version of the original article can be found under doi:10.1186/s12947-016-0053-8.