Prediagnostic serum tocopherol levels and the risk of Non-Hodgkin Lymphoma : The Multiethnic Cohort
Menée sur une cohorte multiethnique incluant 271 patients atteints d'un lymphome non hodgkinien et 538 témoins, cette étude évalue l'association entre les niveaux sériques des tocophérols α, β et δ, avant le diagnostic, et le risque de développer la maladie
Background : Compromised immunity and chronic inflammation are thought to contribute to the development of non-Hodgkin lymphoma (NHL). Because tocopherols protect cells through antioxidant mechanisms, they may play a role in NHL etiology. Methods : This nested case-control study within the Multiethnic Cohort examined the association of prediagnostic serum tocopherols levels measured in 271 NHL cases and 538 matched controls by high pressure liquid chromatography/photodiode-array detection with NHL risk. Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CI). Results : We observed U-shaped associations with NHL for total and α-tocopherols (Ptrend<0.01 for polynomial terms [3 df]). The ORs (95% CI) for total tocopherols, which consisted primarily of α-tocopherol, were 0.41 (0.25-0.68), 0.52 (0.32-0.85), 0.39 (0.23-0.65), and 0.78 (0.47-1.29) for the 2nd-5th quintiles as compared to the 1st. The risk estimates were similar for α-tocopherol but non-significant for β- and γ-tocopherol combined and for δ-tocopherol. Adjustment for serum lipids strengthened the non-linear associations for total and α-tocopherols. Serum total tocopherol levels were higher for vitamin E supplement users at cohort entry than non-users (21.32±9.04 vs 17.72±7.43 μg/mL; P <0.0001), but supplement use was not associated with NHL risk. No heterogeneity in risk estimates was detected by sex, ethnicity, vitamin E supplement use, or NHL subtype. Conclusions : Circulating tocopherols, at levels likely reflecting adequate dietary intakes, may be protective against NHL, whereas higher intakes from supplementation may not be beneficial. Impact : The association between serum tocopherol levels and NHL risk provides possible new insights into the etiology of NHL.