Résumé
Daily dietary intakes of nitrate, nitrite and vitamin C were investigated in Chanle county, Fujian province, where gastric cancer was very common, with a marked geographic variation in mortality. The average daily intake of nitrate of residents in Zhanggang village (high risk area) was 132.75 mg, which was significantly higher than that (84.65 mg) in Shouzhan village (moderate risk area), but similar to that (113.12 mg) in Meihua village (low risk area). However, nitrite intake in Zhanggang village was greatly higher than that in Shouzhan and Meihua villages (3.36 mg vs 0.21 and 0.37 mg, respectively). The average daily intake of vitamin C in Shouzhan village was 56.37 mg, significantly lower than that in Zhanggang village (123.09 mg) and in Meihua village (105.90 mg). The molar ratio of vitamin C intake to nitrite in the three villages was 3.22, 3.30 and 4.33, respectively. It was invesely associated with the mortality of gastric cancer. The results suggested that nitrate and nitrite might be etiological factors of gastric cancer in the county.