Authors’ contributions
VH and BvdB had full access to all of the data in the study and take
responsibility for the integrity of the data and the accuracy of the
data analysis.
Study concept and design: VH, DB and BvdB
Acquisition of data: VH and BvdB
Statistical analysis an interpretation of data: VH, CvdE, LvD, JV, DB
and BvdB
Drafting of the manuscript: VH and BvdB
Critical revision of the manuscript for important intellectual content:
VH, CvdE, LvD, JV, DB and BvdB
Study supervision: BvdB
All authors have read and approved the final version of this manuscript.