A Nested Case–Control Study on Plasma Vitamin E and Risk of Cancer: Evidence of Effect Modification by Selenium [Erratum: July 2019, v.119(7), p.1210]

Evidence from epidemiologic studies has been inconsistent regarding the role of vitamin E in cancer incidence risk.The aim of this study was to evaluate the prospective association between baseline plasma vitamin E levels and subsequent cancer risk in Chinese adults with hypertension, and to identify effect modifiers.A nested, case–control study was conducted from 20,702 hypertensive participants in the China Stroke Primary Prevention Trial, a randomized, double-blind, controlled trial, conducted from May 2008 to August 2013.The current study included 229 new cancer cases and 229 controls matched for age (±1 year), sex, treatment group, and study site.Plasma vitamin E was measured by liquid chromatography with tandem quadrupole mass spectrometers and plasma selenium was measured by inductively coupled plasma mass spectrometry using Thermo Fisher iCAP Q ICP-MS.Odds ratios (OR) of cancer in relation to plasma concentrations of vitamin E were calculated using conditional logistic regression models.Median follow-up duration was 4.5 years. Overall, vitamin E was not associated with subsequent risk of total cancer (per 1-mg/L [2.3 μmol/L] increase: OR 1.01, 95% CI 0.93 to 1.09) and non-gastrointestinal cancer (OR 1.10, 95% CI 0.98 to 1.24). However, there was a significant, inverse association between vitamin E and gastrointestinal cancer (OR 0.86, 95% CI 0.75 to 0.99), particularly esophageal cancer (OR 0.67, 95% CI 0.48 to 0.95). Moreover, high vitamin E decreased the risk of total cancer (OR 0.91, 95% CI 0.84 to 0.99) and gastrointestinal cancer (OR 0.83, 95% CI 0.73 to 0.95) among patients with high selenium levels (median≥83.7 μg/L [1.1 μmol/L]), and increased the risk of total cancer (OR 1.13, 95% CI 1.00 to 1.26) and non-gastrointestinal cancer (OR 1.25, 95% CI 1.03 to 1.50) among those with low selenium levels (<83.7 μg/L [1.1 μmol/L]).This study suggests that higher levels of plasma vitamin E are associated with reduced risk of gastrointestinal cancer. High vitamin E decreased the risk of total cancer among patients with high selenium levels, but increased the risk of total cancer among those with low selenium levels.