Folate intake and stomach cancer incidence in a prospective cohort of Swedish women.
ABSTRACT Experimental and epidemiologic evidence suggests that folate may play a role in the development of some cancers. Case-control studies and one prospective cohort study on folate intake in relation to stomach cancer risk have yielded inconsistent results.
We prospectively investigated the relation between folate intake and the incidence of stomach cancer among 61,433 women in the Swedish Mammography Cohort. Participants completed a food frequency questionnaire at baseline (1987-1990) and again in 1997. During follow-up through December 2004, 156 incident stomach cancer cases were diagnosed. Cox proportional hazards models were used to calculate multivariate-adjusted hazard ratios.
There was no association between dietary folate intake (i.e., folate from food sources) and the risk of stomach cancer. The multivariate hazard ratio for the highest compared with the lowest category of updated average dietary folate intake was 1.04 (95% confidence interval, 0.61-1.86; P(trend) = 0.91). The relation between dietary folate intake and stomach cancer did not vary significantly by intake of alcohol, methionine, or caffeine.
Results from this prospective study do not support an association between dietary folate intake and risk of stomach cancer.
Article: The association of gastric cancer risk with plasma folate, cobalamin, and methylenetetrahydrofolate reductase polymorphisms in the European Prospective Investigation into Cancer and Nutrition.[show abstract] [hide abstract]
ABSTRACT: Previous studies have shown inconsistent associations of folate intake and polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene with gastric cancer risk. Our nested case-control study within the European Prospective Investigation into Cancer and Nutrition cohort is the first prospective study of blood folate levels and gastric cancer. Gastric cancer cases (n=247) and controls (n=631) were matched for study center, age, sex, and time of blood donation. Two common single nucleotide polymorphisms of the MTHFR gene were determined, as were plasma concentrations of folate, cobalamin (vitamin B12), total homocysteine, and methylmalonic acid (cobalamin deficiency marker) in prediagnostic plasma. Risk measures were calculated with conditional logistic regression. Although no relations were observed between plasma folate or total homocysteine concentrations and gastric cancer, we observed a trend toward lower risk of gastric cancer with increasing cobalamin concentrations (odds ratio, 0.79 per SD increase in cobalamin; P=0.01). Further analyses showed that the inverse association between cobalamin and gastric cancer was confined to cancer cases with low pepsinogen A levels (marker of severe chronic atrophic gastritis) at the time of blood sampling. The 677 C-->T MTHFR polymorphism was not associated with gastric cancer, but we observed an increased risk with the variant genotype of the 1298 A-->C polymorphism (odds ratio, 1.47 for CC versus AA; P=0.04). In conclusion, we found no evidence of a role of folate in gastric cancer etiology. However, we observed increased gastric cancer risk at low cobalamin levels that was most likely due to compromised cobalamin status in atrophic gastritis preceding gastric cancer.Cancer Epidemiology Biomarkers & Prevention 11/2007; 16(11):2416-24. · 4.12 Impact Factor
Article: Vitamins B2 and B6 and genetic polymorphisms related to one-carbon metabolism as risk factors for gastric adenocarcinoma in the European prospective investigation into cancer and nutrition.[show abstract] [hide abstract]
ABSTRACT: B vitamins and polymorphisms in genes coding for enzymes involved in one-carbon metabolism may affect DNA synthesis and methylation and thereby be implicated in carcinogenesis. Previous data on vitamins B2 and B6 and genetic polymorphisms other than those involving MTHFR as risk factors for gastric cancer (GC) are sparse and inconsistent. In this case-control study nested within the European Prospective Investigation into Cancer and Nutrition cohort, cases (n = 235) and controls (n = 601) were matched for study center, age, sex, and time of blood sampling. B2 and B6 species were measured in plasma, and the sum of riboflavin and flavin mononucleotide was used as the main exposure variable for vitamin B2 status, whereas the sum of pyridoxal 5'-phosphate, pyridoxal, and 4-pyridoxic acid was used to define vitamin B6 status. In addition, we determined eight polymorphisms related to one-carbon metabolism. Relative risks for GC risk were calculated with conditional logistic regression, adjusted for Helicobacter pylori infection status and smoking status. Adjusted relative risks per quartile (95% confidence interval, P(trend)) were 0.85 (0.72-1.01, 0.06) for vitamin B2 and 0.78 (0.65-0.93, <0.01) for vitamin B6. Both relations were stronger in individuals with severe chronic atrophic gastritis. The polymorphisms were not associated with GC risk and did not modify the observed vitamin-cancer associations. In summary, results from this large European cohort study showed an inverse association between vitamin B2 and GC risk, which is borderline significant, and a significant inverse association between vitamin B6 and GC risk.Cancer Epidemiology Biomarkers & Prevention 01/2010; 19(1):28-38. · 4.12 Impact Factor