1 From the Departments of Internal Medicine and Community Health Sciences (R.A.M.), University of Manitoba, Canada; and Department of Biostatistics and Computational Biology (C.A.B.), University of Rochester Medical Center, NY. rmarrie@hsc.mb.ca.
2 From the Departments of Internal Medicine and Community Health Sciences (R.A.M.), University of Manitoba, Canada; and Department of Biostatistics and Computational Biology (C.A.B.), University of Rochester Medical Center, NY.