Contribution to authorship:
AA&HB&AB&MD designed the study. HB&AB had full access to all of the
data in the study and takes responsibility for the integrity of the data
and the accuracy of the data analysis. HB&AB acquired the data and
performed statistical analysis. AA&MP wrote and drafted the manuscript.
MD contributed to study design and to statistical analysis and
interpretation of data. All authors provided critical revision of the
manuscript.