Selected micronutrient intake and the risk of gastric cancer.

The relationship between intake of selected micronutrients and gastric cancer risk was investigated using data from a case-control study conducted in Italy between 1985 and 1992 on 723 cases of histologically confirmed, incident gastric cancer, and 2024 controls hospitalized for acute, nonneoplastic, nondigestive tract diseases. Relative risks of subsequent quintiles of intake were computed after allowance for sex, age, and other major identified potential confounding factors, including an estimate of total calorie intake. No trend in risk emerged for intake of retinol, vitamin D and vitamin E, whereas a protective pattern was observed for consumption of beta-carotene, ascorbic acid, folate, and nitrates, with risk estimates for the highest intake quintiles of 0.27, 0.40, 0.58, and 0.43, respectively. Significant direct trends in risk were found for methionine, calcium, and nitrites. When the effect of various micronutrients was taken into account, a residual protective effect was observed for beta-carotene and ascorbic acid, and a direct association with methionine remained, whereas the protective effect of folates and nitrates and the direct associations of nitrites were no longer evident. The risk estimates for the upper quintiles of beta-carotene, ascorbic acid, and methionine consumption were respectively 0.38, 0.53, and 2.40, and all the trends in risk were significant and consistent across strata of sex and age. Whether this reflects a specific effect of these micronutrients, rather than problems of collinearity or other limitations of the data, is open for discussion. Nonetheless, these data indicate that selected micronutrients may have an impact in the process of gastric carcinogenesis.