MAIN MANUSCRIPT - Submitted to New England Journal of Medicine on February 22, 2002. On May 10, 2002, New Englad Journal of Medicine rejected the manuscript. Manuscript was submitted to LANCET on June 17, 2002 and rejected on July 29, 2002. Manuscript was submitted to JAMA on August 30, 2002 and rejected on September 6, 2002. Manuscript has been resubmitted to JAMA on March 24, 2003.