Associations between Plasma Tocopherols and Lung Cancer Risk: Results from the Southern Community Cohort Study

Abstract

Background: Despite the various anticancer activities of tocopherols, little is known about tocopherols associated with lung cancer risk among low-income African Americans (AAs) and European Americans (EAs) who are disproportionately affected by the disease. Methods: We conducted a nested case-control study that included 209 incident lung cancer cases and 406 matched controls within the Southern Community Cohort Study. Using biospecimens collected at cohort enrollment, plasma levels of α-, β/γ-, δ-, and total-Tocopherols were measured by high-performance liquid chromatography with photo-diode array detection. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% CIs for lung cancer risk after adjusting for potential confounders. Stratified analyses were also conducted. Results: Plasma levels of total-Tocopherols were inversely associated with lung cancer risk overall (OR [95% CI] for the highest vs. lowest tertile=0.51 [0.30-0.90]). The inverse association remained significant among EAs (0.20 [0.06-0.65]), men (0.43 [0.21-0.90]), current smokers (0.49 [0.26-0.93]), and cases diagnosed within two years of blood draw (0.36 [0.15-0.86]), though we did not find a significant risk reduction among AAs (0.75 [0.39-1.45]). Notably, we found significant interactions between α-Tocopherol and race after controlling the false discovery rate to correct for multiple comparisons (p-interaction=0.02). Conclusions: Our results indicate that plasma total-Tocopherols are inversely associated with lung cancer risk, but the association may differ across specific isomeric forms of tocopherols, race, or other individuals' characteristics. Further large-scale studies are warranted to confirm our findings. Impact: Recommendations on tocopherols for lung cancer prevention should take isomers, race, and smoking behaviors into consideration.