Bastiaan Sallevelt

23 General Introduction Declarations Authors’ contributions Bastiaan Sallevelt wrote the general introduction of this thesis. His supervisors Wilma Knol, Ingeborg Wilting, Eugène van Puijenbroek and Toine Egberts reviewed the manuscript critically for important intellectual content and approved the final version. Acknowledgement Bastiaan would also like to thank his parents, who reviewed the general introduction on comprehensibility for people not professionally involved in the field of medicine. Competing interests The author(s) declare that they have no competing interests. 1