Accepted for Publication: December 20, 2012.
Author Contributions: All authors had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Tribó. Acquisition of data: Tribó, Rozas-Muñoz, Gallardo, Casanova, and Pujol. Analysis and interpretation of data: Tribó, Casanova, Ros-Montalban, and Bulbena. Drafting of the manuscript: Tribó and Rozas-Muñoz. Critical revision of the manuscript for important intellectual content: Tribó, Gallardo, Casanova, Ros-Montalban, Bulbena, and Pujol. Statistical analysis: Tribó and Rozas-Muñoz. Administrative, technical, and material support: Casanova. Study supervision: Tribó, Gallardo, Ros-Montalban, Bulbena, and Pujol.
Financial Disclosure: None reported.