1. Department of Epidemiology and Biostatistics School of Public Health, Texas A&M University, College Station, TX, USA;
2. Department of Statistics, Texas A&M University, College Station, TX, USA;
3. Global Medical Affairs Andrology, Bayer AG, Berlin, Germany and Research Department, Gulf Medical University, Ajman, UAE;
4. Private Urology Practice, Bremerhaven, Germany