Y Kuroda wrote the first draft of the manuscript, and all authors participated in writing the subsequent drafts and agreed to submit this manuscript for publication. Y Kuroda, H Abe, T Ito-Ihara, R Asada, S Morita, S Matsuda and H Akiyama were responsible for study conception, trial design, obtaining grant funding and trial management. T Tanaka, T Miyagawa, H Hamada, Y Fujimoto, D Takahashi, T Tetsunaga, A Kaneuji, M Takagi, Y Inaba, N Sugano and S Tanaka were responsible for data acquisition. H Abe and S Morita were responsible for the statistical analysis. All authors were responsible for the data interpretation and for drafting and approving the final submitted manuscript. List of the TRION collaborators: Tsuyoshi Asano, Juji Ito, Hirofumi Oshima, Taizo Kaneko, Yoko Fukasawa, Hyonmin Choe, Shusuke Ueda, Kayoko Enomoto, Harue Tada, Akiko Kuroda, Yasuhiko Tabata, Yaichiro Okuzu, Toshiyuki Kawai, Koji Goto, Manabu Nankaku, Masaki Takao, Wataru Ando, Kazuki Yamada, Michio Yamamoto, Takashi Sakai, Yasuhiro Ishidou, Shigeru Yamada, Hidetsugu Ohara, Hiroshi Fujita, Hirotsugu Ohashi, Hirokazu Iida, Takashi Nakamura.