Vitamin E intake and risk of esophageal and gastric cancers in the NIH-AARP Diet and Health Study.Int J Cancer 2009; 125(1):165-70IJ
We investigated the association of dietary alpha-tocopherol, gamma-tocopherol and supplemental vitamin E intake with the risk of esophageal squamous cell carcinoma (n = 158), esophageal adenocarcinoma (n = 382), gastric cardia adenocarcinoma (n = 320) and gastric noncardia adenocarcinoma (GNCA; n = 327) in the NIH-AARP Diet and Health Study, a cohort of approximately 500,000 people. Data on dietary and supplemental vitamin E intake were collected using a validated questionnaire at baseline and were analyzed using Cox regression models. Intakes were analyzed as continuous variables and as quartiles. For dietary alpha-tocopherol, we found some evidence of association with decreased esophageal squamous cell carcinoma and increased esophageal adenocarcinoma risk in the continuous analyses, with adjusted hazard ratios and 95% confidence intervals of 0.90 (0.81-0.99) and 1.05 (1.00-1.11), respectively, per 1.17 mg (half the interquartile range) increased intake. However, in quartile analyses, the p value for trend was nonsignificant for both these cancers. There was no association between dietary alpha-tocopherol and gastric cardia adenocarcinoma or GNCA. We observed no statistically significant associations with gamma-tocopherol. For supplemental vitamin E, the results were mainly null, except for a significantly lower risk of GNCA with higher doses of supplemental vitamin E. An increase of 71 mg/day (half the interquartile range) in supplemental vitamin E had an hazard ratio (95% confidence interval) of 0.92 (0.85-1.00) and the p value for trend in the quartile analysis was 0.015.