1. Departments of Family and Community Medicine and of Epidemiology, The University of Texas Health Science Center , Houston, TX, USA
2. Department of Surgical Sciences, Uppsala University , Uppsala, Sweden
3. Department of Urology, Stanford University School of Medicine , Stanford, CA, USA
4. Center for Primary Health Care Research, Department of Clinical Sciences, Lund University , Malmö, Sweden
5. Department of Psychiatry, Virginia Commonwealth University , Richmond, VA, USA
6. Department of Epidemiology, The University of Texas M.D. Anderson Cancer Center , Houston, TX, USA