1. Division of Gastroenterology; Hepatology and Nutrition; Vanderbilt University Medical Center; Nashville; Tennessee; U.S.A.
2. Department of Biostatistics; the Vanderbilt Voice Center; Vanderbilt University Medical Center; Nashville; Tennessee; U.S.A.
3. Department of Otolaryngology; Vanderbilt University Medical Center; Nashville; Tennessee; U.S.A.
4. Allergy, Sinus and Asthma Program; Vanderbilt University Medical Center; Nashville; Tennessee; U.S.A.