Sex-specific association of plasma vitamin E with homocysteine levels in Chinese middle-aged and older men and women: evidence from four large population based studies

Purpose Blood homocysteine (Hcy) levels have become a sensitive predictor of the development of cardiovascular disease. Few studies have reported the relationship between plasma vitamin E and Hcy. We aim to conduct an age- and sex-stratified investigation of the association between vitamin E status and Hcy levels in a large nationwide sample in China. Methods We conducted a cross-sectional study including 15,842 Chinese adults. The exposure variable was plasma vitamin E. The outcome variables included homocysteine level and hyperhomocysteinemia. Multiple linear models and multivariable logistic regression were performed to evaluate the relation between plasma vitamin E and homocysteine. Restricted cubic spline was conducted to examine the non-linear relationship. Results In men, the association between plasma vitamin E and homocysteine level followed a U-shape ( p for nonlinearity < 0.001). Compared with plasma vitamin E value of 8.5 ~ 15.9 ug/ml, the risk of hyperhomocysteinemia increased for values lower than 8.5 ug/ml (OR: 1.33 (1.10,1.60), p  = 0.002) or higher than 15.9 ug/ml (OR: 1.77 (1.25, 2.50), p  = 0.001) in < 65 year-old adults. In men ≥ 65 years old, participants with plasma vitamin E less than 8.3 ug/ml had no significantly associated with hyperhomocysteinemia (OR: 1.22 (1.04,1.43), p  = 0.015). Among women, however, no nonlinear relationship was found regardless of age. ( p for nonlinearity > 0.05), the dose-response relationship between vitamin E and homocysteine showed an L-shape. Conclusions Sex-specific associations between plasma vitamin E and homocysteine levels or hyperhomocysteinemia were found. The relationship was U-shaped in men and L-shaped in women. In contrast to the differences observed between sexes, the association between vitamin Eand homocysteine remained consistent across age groups.