1. From the Institute of Nutrition and Food Hygiene, Chinese Academy of Preventive Medicine, Beijing, China (YX); the Anti-Epidemic Station of Mianning, Sichuan Province, China (JX); the Department of Biostatistics (DWB) and the Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine (KEH and RFB), Vanderbilt University School of Medicine, Nashville, TN.