Low vitamin B(6) plasma levels, a risk factor for thrombosis, in inflammatory bowel disease: role of inflammation and correlation with acute phase reactants

OBJECTIVES: Individuals with inflammatory bowel disease (IBD) are at increased risk for thrombosis and vitamin deficiencies. Low plasma levels of vitamin B6 are an independent risk factor for thrombosis and may cause hyperhomocysteinemia, another recognized risk factor for thrombosis. The aim of this study was to evaluate vitamin B6 plasma levels in IBD patients. METHODS: We studied 61 IBD patients: 32 with Crohn's disease and 29 with ulcerative colitis. For each patient, three sex- and age-matched healthy control subjects were studied. RESULTS: Median vitamin B6 levels were significantly lower in IBD patients (22.0 pmol/L, range 3.6 -231.0) than in controls (31.1 pmol/L, 3.7-363.4; p < 0.01). In all, 13.1% IBD patients and 5.5% controls had plasma vitamin B6 levels lower than the 5th percentile of distribution in normal controls (p < 0.05). Low vitamin B6 levels were significantly more frequent in patients with active disease than in patients with quiescent disease (seven of 26, 26.9%, vs one of 35, 2.9%; p < 0.001). Moreover, patients with active disease had significantly lower median vitamin B6 levels (13.4 pmol/L, range 3.6-124.0) than patients in a quiescent phase (27.0 pmol/L, 7.8-231.0; p < 0.001). Low vitamin B6 levels were significantly correlated with serum concentrations of C-reactive protein (r = -0.36, 95% CI = -0.59 to -0.09, p < 0.01) and α1-acid-glycoprotein (r = -0.37, 95% CI = -0.59 to -0.10, p < 0.01). Hyperhomocysteinemia was more frequent in patients with low vitamin B6 levels (three of eight, 37.5%) than in patients with normal levels (nine of 53, 17.0%; p = 0.18). There was no statistically significant correlation between vitamin B6 and homocysteine plasma levels (r = -0.13, 95% CI = -0.37 to +0.14, p = 0.33). CONCLUSIONS: Low vitamin B6 plasma levels, an independent risk factor for thrombosis, are frequent in patients with IBD, especially those with active disease.