Author Contributions: Drs Sato, Yabe, and Sasaki 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: Tsuji and Sasaki. Acquisition of data: Sato, Yabe, Soma, Tsuji, and Sasaki. Analysis and interpretation of data: Sato, Yabe, Fukuda, Soma, Nakahara, Tsuji, and Sasaki. Drafting of the manuscript: Sato, Yabe, Soma, Tsuji, and Sasaki. Critical revision of the manuscript for important intellectual content: Fukuda, Nakahara, and Tsuji. Statistical analysis: Fukuda and Nakahara. Obtained funding: Sasaki. Administrative, technical, and material support: Sato, Yabe, Soma, Tsuji, and Sasaki. Study supervision: Tsuji and Sasaki.