Author Contributions: Study concept and design: Campo, Saia, and Marzocchi. Acquisition of data: Guastaroba, Ottani, and Tondi. Analysis and interpretation of data: Campo, Saia, Guastaroba, Marchesini, Varani, Manari, De Palma, and Marzocchi. Drafting of the manuscript: Campo, Saia, Guastaroba, Marchesini, and Marzocchi. Critical revision of the manuscript for important intellectual content: Guastaroba, Marchesini, Varani, Manari, Ottani, Tondi, and De Palma. Statistical analysis: Campo, Saia, Guastaroba, and De Palma. Obtained funding: Campo, Varani, De Palma, and Marzocchi. Administrative, technical, and material support: Campo, Saia, Marchesini, Varani, Tondi, and De Palma. Study supervision: Marchesini, Manari, Ottani, and Marzocchi.
Financial Disclosure: None reported.
Funding/Support: This study was supported by contract No. 13 (December 11, 2008), Bando Nazionale Ricerca Finalizzata 2007, Ministero della Salute (Italy).