Ecological study on the risks of esophageal cancer in Ci-Xian, China: The importance of nutritional status and the use of well water

Our purpose was to determine the environmental risks in the development of esophageal cancer in Ci-Xian, which has one of the highest incidences of es ophageal cancer in China. The subjects included 404, 352 and 400 inhabitant s living in high-, medium-, and low-incidence areas of esophageal cancer, a s well as 301 esophageal cancer patients. A food intake-frequency survey us ing a 7-day weighted inventory questionnaire was conducted on these individ uals. Questions on occupation, working conditions, income per year, family disease history, medical complaints, and demographic features were also inc luded in the questionnaire. The levels of nitrogen compounds in selected sa mples of well water were also measured in each of the 3 areas. Clear-cut di fferences in food intake were seen among inhabitants living in the 3 differ ent areas, suggesting that regional differences in nutritional styles do ex ist. In both males and females, the intake of potatoes, fruit, vegetables, and meat were significantly lower in inhabitants living in the high-inciden ce area than in the other inhabitants, much the same as that of cancer pati ents. A low intake of carotene, and vitamins A and C was also seen in popul ations living in the high-incidence area of esophageal cancer. The well wat er polluted with nitrogen compounds was significantly related to the high i ncidence of esophageal cancer. In contrast, tobacco, alcohol consumption, a nd the intake of pickled vegetables and moldy foods did not relate to the d ifferent incidence rates. Our results suggest that low intake of fruit, veg etables, potatoes and meat, and the quality of well water may be important factors in the development of esophageal cancer in Ci-Xian. (C) 1999 Wiley- Liss, Inc.