Affiliation: | 1 Department of Obstetrics and Gynecology, Mayo Clinic College of Medicine, Rochester, MN 2 Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, MN 3 Division of Biostatistics, Mayo Clinic College of Medicine, Rochester, MN 4 Division of Epidemiology, Mayo Clinic College of Medicine, Rochester, MN. |