Jay H Fowke1, John D Potter2. 1. Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN. 2. Fred Hutchinson Cancer Research Center, Seattle, WA Epidemiology Department, School of Public Health, University of Washington, Seattle, WA Centre for Public Health Research, Massey University, Wellington, New Zealand.