Plasma ascorbic acid concentrations are related to cardiovascular risk factors in African-Americans

This study was undertaken to examine relationships among blood pressure, blood lipids, and plasma concentrations of ascorbic acid and malondialdehyde (MDA) equivalents (indicative of lipid peroxidation) in adult African-Americans. Subjects (n = 172, mean age = 48.0 y) were recruited from among the memberships of several Seventh-Day Adventist Churches. Plasma ascorbic acid and MDA equivalents were inversely correlated (r = -0.44, P < 0.0001). There were significant inverse correlations between plasma ascorbic acid levels and both systolic (r = -0.39, P < 0.0001) and diastolic blood pressure (r = -0.25, P < 0.03), and between plasma ascorbic acid and serum total cholesterol (r = -0.25, P < 0.03), LDL-cholesterol (LDL-C) (r = -0.33, P < 0.004), and the ratio of LDL-cholesterol to HDL-cholesterol (LDL-C/HDL-C) (r = -0.32, P < 0.004). Serum HDL-cholesterol was positively related to plasma ascorbic acid (r = 0.22, P < 0.05). The correlations for MDA equivalents and the blood pressure and blood lipid variables were of similar magnitude to those of plasma ascorbic acid, but were in the opposite direction. Multiple regression analysis revealed ascorbic acid to be a significant independent contributor to the prediction of blood pressure and LDL-C concentration. These data suggest that plasma concentrations of ascorbic acid and MDA equivalents are related to several cardiovascular risk indicators in black Americans.