Serum Vitamin C Concentration Is Low in Peripheral Arterial Disease and Is Associated With Inflammation and Severity of Atherosclerosis

Abstract

Background —Peripheral arterial disease (PAD) is a severe atherosclerotic condition frequently accompanied by inflammation and oxidative stress. We hypothesized that vitamin C antioxidant levels might be low in PAD and are related to inflammation and disease severity. Methods and Results —We investigated vitamin C ( l -ascorbic acid) levels in 85 PAD patients, 106 hypertensives without PAD, and 113 healthy subjects. Serum l -ascorbic acid concentrations were low among PAD patients (median, 27.8 μmol/L) despite comparable smoking status and dietary intake with the other groups ( P <0.0001). Subclinical vitamin C deficiency (<11.4 μmol/L), confirmed by low serum alkaline phosphatase activity, was found in 14% of the PAD patients but not in the other groups. Serum C-reactive protein (CRP) concentrations were significantly higher in PAD patients ( P <0.0001) and negatively correlated with l -ascorbic acid levels ( r =−0.742, P <0.0001). In stepwise multivariate analysis, low l -ascorbic acid concentration in PAD patients 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 patients in association with higher CRP levels and severity of PAD. Future studies attempting to relate vitamin C levels to disease occurrence should include in their analysis an inflammatory marker such as CRP.