A prospective study of vitamin and mineral supplement use and the risk of upper gastrointestinal cancers.

We examined the association of use of multivitamins or single vitamin/mineral supplements with risk of four upper gastrointestinal cancers in the NIH-AARP Diet and Health Study cohort with 11 years of follow-up. After exclusions, 490,593 persons were included in our analytic cohort and 1780 upper gastrointestinal cancers were accrued. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox models with adjustment for potential confounders. We observed no significant associations between multivitamin use and risk for the four cancer outcomes in crude or adjusted models. Among individual vitamin or mineral supplements, use of iron supplements was associated with significantly lower risk of esophageal adenocarcinoma (HR = 0.68, 95% CI = 0.49 to 0.94) and a significantly increased risk of gastric noncardia adenocarcinoma (HR = 1.59, 95% CI = 1.24 to 2.05). For gastric noncardia adenocarcinoma, we saw associations with zinc use (HR = 1.28, 95% CI = 1.01 to 1.62) and vitamin C use (HR = 0.79 95% CI = 0.65 to 0.96). Calcium use, some of which was reported as antacids and used to treat reflux disease, was associated with higher risk of esophageal adenocarcinoma (HR = 1.27, 95% CI = 1.06 to 1.52) and gastric cardia adenocarcinoma (HR = 1.27, 95% CI = 1.03 to 1.56) cancers. We saw no evidence that multivitamin use was associated with reduced risk of four highly fatal upper gastrointestinal cancers, but there were some differences in risk with reported use of individual supplements.