[1] Michael E DeBakey VA Med Ctr, Houston Ctr Qual Care & Utilizat Studies, Houston, TX 77030 USA
[2] Baylor Coll Med, Scott Dept Urol, Houston, TX 77030 USA
[3] Univ So Calif, Keck Sch Med, Dept Urol, Los Angeles, CA USA
[4] Univ So Calif, Keck Sch Med, Dept Prevent Med, Los Angeles, CA USA
[5] Univ Illinois, Sch Publ Hlth, Chicago, IL USA
[6] Genentech Inc, San Francisco, CA 94080 USA
[7] Univ Calif San Francisco, Dept Urol, San Francisco, CA 94143 USA