Food groups and risk of esophageal cancer in Chaoshan region of China: a high-risk area of esophageal cancer.

The current study was designed to investigate the role of common foods in the etiology of esophageal cancer in the Chaoshan region of China. A large case-control study was conducted to investigate 1248 patients with squamous cell carcinoma of the esophagus and 1248 controls matched by sex, age, and hospitals. After adjusting for the effects of sex, age, occupation, areas of residence, income, alcohol intake, and cigarette usage, a strong association with a clear dose-response relationship was observed between the fermented fish sauce eaten weekly and esophageal cancer (P for trend less than 0.001). The results for pickles were similar to those for fermented fish sauce. A protective effect of fruits on esophageal cancer was observed, and this risk decreased (P for trend less than 0.001) as frequencies of fresh fruit intake increased. The risks from sowbelly and kipper were significantly higher in consumers than in nonconsumer, but the dose-response relationship was not statistically significant. No significant effects, however, were detected from vegetables, smoked foods, and so on. To the authors' knowledge, this is the first report on the relationship between fish juice and high risk of esophageal cancer in a population. Further epidemiological and experimental study are required to find a biological causal relationship between them.