Approximately10-20% of the adult population has GERD and 0.5 to 2% of the adult population (1-4 million individuals) is estimated to have BE and it is a known precursor to esophageal adenocarcinoma. However, we are not yet able to reliably identify those individuals with GERD that are at risk for developing BE and with BE who are at high risk for progressing to esophageal adenocarcinoma. The identification of risk factors as the ultimate goal of this study will enable us to better identify the high-risk patients and provide early intervention and therapeutic strategies in a cost-effective manner.