Correlations of dietary intake and blood nutrient levels with esophageal cancer mortality in China.

Using dietary, blood nutrient, and esophageal cancer mortality data from 65 Chinese counties, we examined several correlations to help provide clues to the influence of diet and nutrition on the geographic variation of esophageal cancer in China. Esophageal cancer mortality was significantly inversely related to reported fruit consumption and to plasma ascorbic acid concentration. The age-adjusted mortality rates were more than three times higher for counties in the lowest compared with the highest quartile of fruit intake or plasma vitamin C. Positive correlations with intake of moldy vegetables were observed but not with tobacco and alcohol consumption. There were suggestive inverse associations with blood selenium and riboflavin but little effect of fat-soluble vitamins. Limitations of ecological data preclude causal inferences, but the relationships provide leads to dietary factors that may contribute to the exceptionally high rates of esophageal cancer in several areas of China.