Cholesterol-adjusted vitamin E serum levels are associated with cardiovascular events in patients with non-valvular atrial fibrillation

Abstract

Background: Non-valvular atrial fibrillation is associated with an increase in thromboembolism, i.e. stroke, and atherosclerotic events, i.e. myocardial infarction. Vitamin E possesses anti-coagulant as well as anti-atherosclerotic properties. Our aim was to assess whether vitamin E is associated with cardiovascular events in patients with non-valvular atrial fibrillation.

Methods: Serum levels of cholesterol-adjusted vitamin E were measured in 1012 patients with non-valvular atrial fibrillation. Patients were followed for a mean time of 27.0 months, and cardiovascular events, such as cardiovascular death and fatal and nonfatal stroke or myocardial infarction, were recorded.

Results: During the follow-up period, cardiovascular events occurred in 109 (11%) patients (18 fatal and 14 nonfatal myocardial infarction; 13 fatal and 19 nonfatal ischemic strokes; 45 cardiovascular deaths). Lower vitamin E serum levels were found in patients who experienced cardiovascular events compared to those who did not (3.8±1.2 vs. 4.4±1.8 μmol/mmol cholesterol; p<0.001). Using a Cox proportional hazard model, age, diabetes, history of stroke and myocardial infarction and vitamin E serum levels (HR 0.77; 95% CI: 0.67-0.89; p=0.001) independently predicted cardiovascular events. Patients with vitamin E<4.2 μmol/mmol cholesterol (median values) had an increased risk of cardiovascular events (HR 1.87; 95% CI: 1.25-2.80: p=0.002).

Conclusions: Low vitamin E serum levels are associated with an increased risk of cardiovascular events in patients with non-valvular atrial fibrillation.

Keywords: Atrial fibrillation; Cardiovascular events; Vitamin E.