Background: Vitamin E compounds exhibit prostate cancer preventive properties experimentally, but serologic
investigations of tocopherols, and randomized controlled trials of supplementation in particular, have been inconsistent.
Many studies suggest protective effects among smokers and for aggressive prostate cancer, however.
Methods: We conducted a nested case-control study of serum a-tocopherol and c-tocopherol and prostate cancer risk in
the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, with 680 prostate cancer cases and 824 frequencymatched
controls. Multivariate-adjusted, conditional logistic regression models were used to estimate odds ratios (OR) and
95% confidence intervals (CIs) for tocopherol quintiles.
Results: Serum a-tocopherol and c-tocopherol were inversely correlated (r = 20.24, p,0.0001). Higher serum a-tocopherol
was associated with significantly lower prostate cancer risk (OR for the highest vs. lowest quintile = 0.63, 95% CI 0.44–0.92, ptrend
0.05). By contrast, risk was non-significantly elevated among men with higher c-tocopherol concentrations (OR for the
highest vs. lowest quintile = 1.35, 95% CI 0.92–1.97, p-trend 0.41). The inverse association between prostate cancer and atocopherol
was restricted to current and recently former smokers, but was only slightly stronger for aggressive disease. By
contrast, the increased risk for higher c-tocopherol was more pronounced for less aggressive cancers.
Conclusions: Our findings indicate higher a-tocopherol status is associated with decreased risk of developing prostate
cancer, particularly among smokers. Although two recent controlled trials did not substantiate an earlier finding of lower
prostate cancer incidence and mortality in response to supplementation with a relatively low dose of a-tocopherol, higher
a-tocopherol status may be beneficial with respect to prostate cancer risk among smokers. Determining what stage of
prostate cancer development is impacted by vitamin E, the underlying mechanisms, and how smoking modifies the
association, is needed for a more complete understanding of the vitamin E-prostate cancer relation.