Low vitamin B6 levels and the risk of recurrent venous thromboembolism.

Low plasma vitamin B6, measured as pyridoxal-5'-phosphate (PLP), is associated with an increased risk of first venous thromboembolism (VTE). In a prospective cohort of 757 patients with first VTE we investigated the association of PLP levels with risk of recurrent VTE. After 4 years, the likelihood of VTE recurrence among patients with PLP < or =23.3 nmol/L and 14.4% (11.5%-17.4%) among those with PLP >23.3 nmol/L was 22.5% (95% CI 13.6%-31.5%) (p=0.01). Patients with PLP ''23.3 nmol/L had 1.8-fold higher recurrence risk (1.01-3.14) than patients with PLP >23.3 nmol/L (adjusted for confounders including homocysteine). Therefore, low vitamin B6 is a risk factor of recurrent VTE.