Serum vitamin C concentration is low in peripheral arterial disease and isassociated with inflammation and severity of atherosclerosis

Background-Peripheral arterial disease (PAD) is a severe atherosclerotic co ndition frequently accompanied by inflammation and oxidative stress. We hyp othesized that vitamin C antioxidant levels might be low in PAD and are rel ated to inflammation and disease severity. Methods and Results-We investigated vitamin C (L-ascorbic acid) levels in 8 5 PAD patients, 106 hypertensives without PAD, and 113 healthy subjects, Se rum L-ascorbic acid concentrations were low among PAD patients (median, 27. 8 mu mol/L) despite comparable smoking status and dietary intake with the o ther groups (P<0.0001). Subclinical vitamin C deficiency (<11.4 mu mol/L), confirmed by low serum alkaline phosphatase activity, was found in 14% of t he PAD patients but not in the other groups. Serum C-reactive protein (CRP) concentrations were significantly higher in PAD patients (P<0.0001) and ne gatively correlated with L-ascorbic acid levels (r=-0.742, P<0.0001). In st epwise multivariate analysis, low L-ascorbic acid concentration in PAD pati ents was associated with high CRP level (P=0.0001), smoking (P=0.0009), and shorter absolute claudication distance on a standardized graded treadmill test (P=0.029), Conclusions-Vitamin C concentrations are lower in intermittent claudicant p atients in association with higher CRP levels and severity of PAD. Future s tudies attempting to relate vitamin C levels to disease occurrence should i nclude in their analysis an inflammatory marker such as CRP.