Contribution to authorship
All authors contributed to the conception, planning and carrying out of
the research. DAM conceived and designed the study and wrote the first
draft of this paper. SN, HL and VR helped with acquisition of data. DAM,
SN and HL conducted statistical analyses. SL, PH, HK and PK helped with
design and conception. All authors contributed to critically revising
the paper for important intellectual content and approved the final
version to be published. All authors accept responsibility for the
article as published.