Submitted for Publication: October 25, 2012; final revision received January 16, 2013; accepted April 15, 2013.
Author Contributions: All authors had full access to all 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: Mohamed, El-Anwar, Quriba.
Acquisition of data: Mohamed, Sorour, El-Anwar.
Analysis and interpretation of data: All authors.
Drafting of the manuscript: All authors.
Critical revision of the manuscript for important intellectual content: Mohamed, El-Anwar, Quriba, Mahdy.
Statistical analysis: Quriba.
Obtained funding: Mohamed, Sorour, El-Anwar, Quriba.
Administrative, technical, and material support: El-Anwar, Quriba.
Study supervision: Mohamed, Sorour.
Published Online: August 22, 2013. doi:10.1001/jamaoto.2013.3554.
Conflict of Interest Disclosures: None reported.
Previous Presentation: This study was an oral presentation at the Zagazig Faculty of Medicine Conference; March 23, 2012; Zagazig, Egypt.