Association of serum γ-tocopherol levels with mortality: the Multiethnic Cohort Study

Background/Objectives gamma-Tocopherol has unique properties that protect against nitrogen oxide-mediated cellular damage. To elucidate the potential role of gamma-tocopherol in the aging process, we examined the associations of serum gamma-tocopherol levels with all-cause and cause-specific mortality. Subjects/Methods Among participants in the biorepository subcohort of the Multiethnic Cohort Study, pre-cancer diagnostic serum gamma-tocopherol levels were measured in a subset of 3904 men and 4461 women. Of these, 22.7% of men and 13.5% of women died during a mean follow-up time of 9.6 +/- 2.6 years. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for mortality associated with gamma-tocopherol were estimated by Cox proportional hazards regression. Results Positive associations of serum gamma-tocopherol with all-cause, cancer, and cardiovascular disease mortality (CVD) (P-trend < 0.05) were detected after adjusting for age, race/ethnicity, and serum cholesterol levels. The respective HRs (95% CIs) for the highest versus the lowest sex-specific gamma-tocopherol quartile were 1.43 (1.17-1.74), 1.79 (1.22-2.64), and 1.52 (1.10-2.11) for men and 1.58 (1.25-2.00), 1.59 (1.05-2.41), and 1.59 (1.07-2.37) for women. Associations remained significant for all-cause mortality among women after further adjusting for smoking variables and history of cancer, CVD, diabetes, and hypertension at cohort entry (highest vs. lowest gamma-tocopherol quartile: HR = 1.38; 95% CI = 1.08-1.75; P-trend = 0.005). Overall, associations with all-cause mortality were consistent across race/ethnicity and were significant in three of ten sex-specific racial/ethnic groups in the fully adjusted models, with no interactions between ethnicity and gamma-tocopherol. Conclusions The positive association between gamma-tocopherol and mortality suggests a potential physiological role for gamma-tocopherol in response to pathological conditions.